Microbiology Part 1 Flashcards by Geil Bacus

Color of non lactose fermenter in EMB and MAC
A. pink
B. Blue
C. Violet
D. colorless

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Which of the following toxins requires cell death to be released?
a. Endotoxin
b. neurotoxin
c. enterotoxin
d. cytotoxin

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The aseptic collection of blood cultures requires that the skin be cleansed with:
A. 2% iodine and then 70% alcohol solution
B. 70% alcohol and then 2% iodine or an
iodophor
C. 70% alcohol and then 95% alcohol
D. 95% alcohol only

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Class of BSC where the air is 100% exhausted
to the building
a. Class I
b. Class IlA
C. Class lIB
d. Class Ill

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Which of the following generally refers to
instances where there is a disproportionately larger number of infected
individuals in a fairly short amount of time?
a. Endemic
b. Epidemic
C. Pandemic
d. Outbreak

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Stain for capsule, except:
a. Neisser
b. Muir
C. Anthony’s
d. Hiss

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Correct arrangement in PCR Amplification
a. Annealing, Denaturation, Extension
b. Annealing, Denaturation, Exit
C. Denaturation, Annealing, Exit
D. Denaturation, Annealing, Extension

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Type of growth in slant, except:
a. Flocculent
b. Beaded
C. Rhizoid
d. Filiform

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All of the following are antibiotics that inhibit
protein synthesis, except;
a. Monobactams
b. Tetracycline
c.Aminoglycosides
d. Chloramphenicol

A. MTAC - antibiotics that inhibit protein synthesis
Macrolides, Tetracycline, Aminoglycosides, Chloramphenicol

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Which of the following is resistant to
aminoglycosides?
a. Aerobes synthesis
b. Facultative anaerobes
C. Anaerobes
d. Either Aerobes or Facultative Anaerobes

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Composition of McFarland Standard
a. Sulfuric Acid and Barium Chloride
b. Hydrochloric Acid and Barium Chloride
C. Hydrochloric Acid and Barium Sulfate
d. Sulfuric Acid and Barium Sulfate

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Which of the following bacteria refers to CONS
a. S. aureus and S. epidermidis
b. S. epidermidis and S. saprophyticus
C. S. epidermidis and S. intermedius
d. S. aureus and S. intermedius

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The beta-hemolysis produced by GAS seen
on the surface of a sheep blood agar plate is
primarily the result of
A. StreptolysinS
B. StreptolysinO
C. M protein
d. Streptokinase

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Which one of the following microorganisms is closely associated with dental caries?
a. C. albicans
b. S. mutans
C. S. pyogenes
d. S. epidermidis

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Lysostaphin is used to IV differentiate Staphylococcus from which other genus?
a. Streptococcus
b. Stomatococcus
C. Micrococcus.
d. Planococcus

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Which of the following species of Bacillus is
nonmotile?
a. B. cereus
b. B. subtilis
c. B. anthracis
d. B. thuringiensis

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Causative agent of erysipeloid production
a. S. pyogenes
b. E. rhusiopathiae
c. C. minutissimum
d. Lactobacillus

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CCFA is used for the recovery of
a. Yersinia enterocolitica
b. Yersinia pestis
c. Clostridium perfringens
d. Clostridium difficile

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Minimal branching aerial hyphae, except:
a. Nocardia
b. Rhodococcus
c. Gordonia
d. Tsukamurella

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Partially acid-fast organisms, except:
a. Tsukamurella
b. Gordonia
C. Rhodococcus
d. Streptomyces

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Biochemically, the Enterobacteriaceae are
gram-negative rods that are:
a. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative
b. Ferment glucose, produce indophenol
oxidase, and form gas
c. Ferment lactose and reduce nitrite to
nitrogen gas
d. Ferment lactose and indophenol oxidase

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What is the pH indicator incorporated in
SSA?
a. Neutral Red
b. Phenol Red
c. Bromthymol blue
d. Bromcresol purple

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Which of the following refers to biochemical test used to separate
Staphylococci, Micrococci from Streptococci?
A. Coagulase
B. Catalase
C. Modified Oxidase
D. Bacitracin

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Which of the following must be incubated in a microaerophilic environment for optimal recovery of the organism?
a. E. coli
b. P. aeruginosa
c. C. jejuni
d. P. mirabilis

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In the following pairs of organisms, which two are hardest to distinguish from each other by Gram stain? a. Micrococcus, Streptoccous b. Neisseria, Microccus C. Bacillus, Sarcina d. Clostridium, Veilonella

Stage of bacterial growth where the organisms become susceptible to antibiotics A. Lag B. Log C. Stationary d. Death

Organism with yellow colonies on TCBS a V. cholerae b. V. parahaemolyticus C. V. mimicus d. V. vulnificus

The species of Vibrio closely associated with rapidly progressing wound infections seen in patients with underlying liver disease is a. V. alginolyticus b. V. cholerae c. V. vulnificus d. V. parahaemolyticus

Which of the following Haemophilus does not require X and V Factor? a. H. influenzae b. H. ducreyi C. H. parahaemophilus D. H. aphrophilis

Causative agent of Cat-scratch disease a. B. bacilliformis b. B. quintana C. B. hensenlae D. B. elizabethae

Which of the following dyes are used to differentiate Brucella species? a. Wright and Giemsa b. Methylene blue and Basic Fuchsin c. Thionine and Basic Fuchsin d. Basic Fuchsin and Giemsa

VP (+) and MR (-) Enterobacteriaceae a. Klebsiella b. E. coli c. Salmonella d. Shigella

Also known as the Hansen's bacillus a. M. tuberculosis b. M. kansasil C. M. leprae d. M. terrae

Part of MTB Complex, except: a. M. bovis b. M. africanum c. M. kansasii d. M. microti

Vector of B. burgdorferi a. Ticks b. Mites C.Louse d. Chigger

Father of Modern Epidemiology a. John Snow b. Robert Koch C. Joseph Lister d. Ignaz Semmelweis

Laboratory results are example of a a. Sign b. Symptoms c. Both d. None of these

Colony elevation a. Umbonate b. Curled C. Rhizoids d. Filamentous

Which of the following organism has a characteristic of "Green metallic sheen on BAp" a. P. aeruginosa b. E. coli C. Enterobacter d. Y. enterolitica

Biological indicator of Autoclave a. B. stearothermophilus b. B. subtilis var. niger C. B. pumilis d. B. subtilis var. globijii

Used for sterilization of culture media that are egg-based and of high protein content a. Autoclave b Inspissation C. Tyndallization d. Incineration

Trimethoprim-sultamethoxazole discs are used along with bacitracin disks to differentiate which streptococci? a. a-Hemolytic streptococci b. beta Hemolytic streptococci c. Streptococcus pneumoniae d. Enterococcus faecalis

Color of positive hydrolysis test a. Yellow b. Purple c. Green d. Red

Which of the Neisseria spp. produces acid from glucose but not from maltose, lactose, or sucrose? a. Neisseria gonorrhoeae b. Neisseria lactamica C. Neisseria meningitidis D. Neisseria sicca

Martin Lewis medium contains the following, except: a. Vancomycin b. Colistin c. Anisomycin d. Nystatin

Campylobacter spp. are associated most frequently with cases of a. Osteomyelitis b. Gastroenteritis c. Endocarditis d. Appendicitis

Routine laboratory testing for T pallidum involves a. Culturing b. Serological analysis C. Acid-fast staining d. Gram staining

Which of the following specimens routinely decontaminated when trying to recover Mycobacterium spp? a. Sputum b. Blood C. Bronchial washing d. NP swab

Lumpy jaw is caused by: a. C. tetani b. A. israeli C. B. anthracis C. botulinum

Spirillum minus also causes rat-bite fever in humans and is referred to as: a. Haverhill fever b. Legionnaire's disease C. Hantavirus d. Sodoku

In thioglycolate broth medium, where do you find facultative anaerobe? a. Middle of the tube b. At the bottom of the tube C. At the top of the tube d. Evenly spread in the tube

Which of the following refers to livingtogether of two unlike organisms whose dependence on each other when broken apart life will still be possible? a. Symbiosis b. Commensalism c. Mutualism d. Parasitism

Host that harbors sexual stage of parasites,where parasites complete their development. a. Definitive Host b. Intermediate Host C. Paratenic Host d. Transfer Host

The O&P examination comprises three separate protocols, except: a. Direct wet mount b. Parasite Culture Method C. Concentration techniques d. Permanent stained smear

FECT arrange from top to bottom a. Ether > Debris > Formalin > Sediment b. Debris > Formalin > Ether> Sediment C. Formalin > Debris > Ether > Sediment d. Ether > Formalin > Debris » Sediment

What is the specific gravity of 33% Zinc Sulfate to be used if the specimen is formalinized? a. 1.020 b. 1.018 c. 1.18 d. 1.20

Mode of transmission: improperly cooked fish a. T. solium b. E. histolytica C. A. duodenale d. C. sinesis

Soil-transmitted helminths, except: a. A. duodenale b. Ascaris C. Strongyloides d. Leishmania

Which of the following enteric parasites resemble macrophages in stool sample? a. E. histolytica cyst b. E. histolytica trophozoite c. Yeast d. pollen grains

Amoeba that inhabits the Gl tract of man are non-motile, non-feeding, and infective during which stage? a. Cyst b. Trophozoite C. Pseudopod d. Cryptozoite

Alcaligenes faecalis is distinguished from Bordetella bronchiseptica with which test? a. Urease b. Oxidase c. Growth on MacConkey agar d. Motility

Characteristics of the rhabditiform larvae of Hookworms include a: a. Short buccal capsule and large genital primordium b. Long buccal capsule and pointed tail C. Long buccal capsule and small genital primordium d. Small genital primordium and notch in tail

Which species of malaria parasite usually has band shaped trophozoite? a. Plasmodium ovale b. Plasmodium falciparum c. Plasmodium malariae d. Plasmodium vivax

Which of the following is the largest Trichomonas and covers almost 50% of its body with undulating membrane? a. T. vaginalis b. T. hominis C. T. tenax d. T. bucalis

Which of the following is the vector of Onchocerca? a. Culex spp b. Chrysops spp. c. Mansonia spp. d. Simulium spp.

What is the recommended drug for treatment of Fasciola infection? a. Chloroquine b. Bithionol c. Albendazole d. Ivermectin

Which Schistosoma species has terminal spine? a. S. haematobium b. S.japonicum C. S. mansoni d. S. mekongi

It resembles egg of S. haematobium, but acid-fast positive a. S. intercalatum b. S.japonicum c. S. mansoni d. S. mekongi

Pseudophyllidean requires how intermediate hosts in their life cycle? a. 1 b. 2 C. 3 D. None

Egg of D. latum may be mistaken a. P. westermanni egg b. Fasciola egg c. Hymenolepis egg d. E. granulosus egg

Which of the following Taenia spp. has 5-12 finger-like, uterine branches? a. T. solium b. T. saginata C. T. asiatica d. T. multiceps

Microsporum infection involves: a. Hair, skin, and nails b. Hair and skin c. Skin and nails d. None of the above

B. Hair, skin and nail- Trichophyton Nail and skin- Epidermophyton

Used to differentiate M. audouinii from M. canis and M. gypseum a. Rice medium b. Czapeck c. Cornmeal agar d. Potato dextrose agar

Which of the following is the most common cause of chromoblastomycosis? a. Exophiala jeanselmei b. Phialiphora verrucosum C. Pseudoallescheria boydii d. Fonsecaea pedrosoi

All of the following fungi can cause Phaehypomycosis, except: a. Alternaria b. Bipolaris C. Wangiella d. Fonsecaea

All of the following can cause White Granules Mycetoma, except: a. Madurella b. Scedosporidium C. Pseudoallescheria d. Acremonium

Which dematiaceous mold forms flask- shaped phialides, each with a flask-shaped collarette? a. Phialophora spp. b. Exophiala spp. c. Wangiella spp. d. All of these options

Trichophyton rubrum and T. mentagrophytes may be differentiated by the a. Consistently different appearance of their colonies b. Endothrix hair infection produced by T. rubrum c. Fluorescence of hairs infected with T. rubrum d. In vitro hair penetration by T. mentagrophytes

Hyaline septate hyphae, branched Or unbranched conidiophores, and multicelled banana-shaped conidia are characteristic of which of the following? a.Fusarium b. Curvularia C. Acremonium d. Trichophyton

All of the following fungi can produce arthroconidia, except: a. Coccidiodes b. Trichosporon c. Geotrichum d. Candida

Which of the following refers to a large yeast with single bud on broad base? a. Paracoccidioides brasiliensis b. Sporothrix schenckii c. Coccidioides immitis d. B. dermatitidis

Fungal colony a. Verrucose b. Umbonate C. Rugose d. Velvety

What is the 2nd step in the identification of unknown yeast isolate? a. Germ tube b. Morphology on cornmeal agar C. CHO Utilization d. India Ink

Infectious form of fungi a. Yeast b. Mold C. Sexual d. Asexual

A black pigment produced by colonies growing on bird seed agar is due to a. Urease b. Phenol oxidase c. Sucrose assimilation d. Arthroconidia production

Used as a stain-preservative for fungi a. PAS Stain. b. Gomori Methenamine Silver C. Lactophenol cotton blue d. Giemsa stain

Viral transport medium containing penicillin, gentamicin and amphotericin is used to collect and transport specimen for virus culture because this medium: a. Enables rapid viral growth during transport time b. Inhibits bacterial and fungal growth C. Destroys nonpathogenic viruses d. Inhibits complement-fixing antibodies

EBV is associated with following? a. Chickenpox b. Hodgkin lymphoma c. Burkitt lymphoma d. Smallpox

Colds and other acute respiratory diseases are most often associated with: a. EBV b. Adenovirus C. Coxsackie virus d. Reovirus

The genus of virus associated with anogenital warts, cervical dysplasia and neoplasia is; a. HSV b. HPV c. CMV d. RSV

An RNA virus that has a nuclear phase to its replication process is a. Coronavirus b. Rhabdovirus c. Togavirus d. Retrovirus

Which of the following refers to "Break bone fever"? a. Coxsackie A virus b. Dengue virus c. Hanta virus d. Rubella virus

Specimen of choice for detecting rotavirus a. Feces sample b. Urine sample c. Bronchoalveolar wash d. Throat swab

A new reverse transcriptase has been discovered. In addition to its effect on HIV disease, it should be checked for its potential in treating a. Infectious hepatitis b. Infectious mononucleosis C. Measles d. Serum hepatitis

D. Serum hepatitis or Hepa B- both transmitted in serum

Arboviruses, except: a. Togavirus b. Flavivirus C. Picornavirus d. Bunyavirus

C. Arbovirus- carried by vectors

Which virus has been implicated in adult gastroenteritis resulting from ingestion of contaminated food and water? a. Norwalk-like virus b. Rotavirus c. Coronavirus d. Hepatitis A virus

Kaposi sarcoma is associated with infection by a. Adenovirus b. CMV c. HHV-8 d. Hepatitis E virus

Enveloped, long, filamentous and irregular capsid forms with single-stranded RNA a. Coronavirus b. Filovirus c. Adenovirus d. Polyomavirus

Most common symptoms of COVID-19, except: a. Fever b. Dry cough c. Tiredness d. Headache

Many of the symptoms of COVID-19 are common to other respiratory or viral illnesses, appears to be more specific to COVID-19 a. Sore throat b. Fever C. Loss of ability to smell (anosmia) d. Shortness of breath

Few persons with SARS were identified as a. Super human b. Super spreaders c. Case d. Contact

The aseptic collection of blood cultures requires that the skin be cleansed with: A. 2% iodine and then 70% alcohol solution B. 70% alcohol and then 2% iodine or an iodophor C. 70% alcohol and then 95% alcohol D. 95% alcohol only

What is the purpose of adding 0.025%–0.050% sodium polyanetholsulfonate (SPS) to nutrient broth media for the collection of blood cultures? A. It inhibits phagocytosis and complement B. It promotes formation of a blood clot C. It enhances growth of anaerobes D. It functions as a preservative

A flexible calcium alginate nasopharyngeal swab is the collection device of choice for recovery of which organism from the nasopharynx? A. Staphylococcus aureus B. Streptococcus pneumoniae C. Corynebacterium diphtheriae D. Bacteroides fragilis

Semisolid transport media such as Amies, Stuart, or Cary–Blair are suitable for the transport of swabs for culture of most pathogens except: A. Neisseria gonorrhoeae B. Enterobacteriaceae C. Campylobacter fetus D. Streptococcus pneumoniae

The aseptic collection of blood cultures requires that the skin be cleansed with: A. 2% iodine and then 70% alcohol solution B. 70% alcohol and then 2% iodine or an iodophor C. 70% alcohol and then 95% alcohol D. 95% alcohol only

When cleansing the skin with alcohol and then iodine for the collection of a blood culture, the iodine (or iodophor) should remain intact on the skin for at least: A. 10 sec B. 30 sec C. 60 sec D. 5 min

All of the following are appropriate when attempting to isolate N. gonorrhoeae from a genital specimen except: A. Transport the genital swab in charcoal transport medium B. Plate the specimen on modified Thayer–Martin (MTM) medium C. Plate the specimen on New York City or Martin–Lewis agar D. Culture specimens in ambient oxygen at 37°C

Chocolate agar and modified Thayer–Martin agar are used for the recovery of: A. Haemophilus spp. and Neisseria spp., respectively B. Haemophilus spp. and N. gonorrhoeae, respectively C. Neisseria spp. and Streptococcus spp., respectively D. Streptococcus spp. and Staphylococcus spp., respectively

Cycloserine–cefoxitin-fructose agar (CCFA) is used for the recovery of: A. Yersinia enterocolitica B. Yersinia intermedia C. Clostridium perfringens D. Clostridium difficile

Deoxycholate agar (DCA) is useful for the isolation of: A. Enterobacteriaceae B. Enterococcus spp. C. Staphylococcus spp. D. Neisseria spp.

Xylose lysine deoxycholate (XLD) agar is a highly selective medium used for the recovery of which bacteria? A. Staphylococcus spp. from normal flora B. Yersinia spp. that do not grow on Hektoen agar C. Enterobacteriaceae from gastrointestinal specimens D. Streptococcus spp. from stool cultures

A sheep blood agar plate is used as a primary isolation medium when all of the following organisms are to be recovered from a wound specimen except: A. β-Hemolytic streptococci and coagulase-positive staphylococci B. Haemophilus influenzae and Haemophilus parainfluenzae C. Proteus spp. and Escherichia coli D. Pseudomonas spp. and Acinetobacter spp.

Prereduced and vitamin K1-supplemented blood agar plates are recommended isolation media for: A. Mycobacterium marinum and Mycobacterium avium intracellulare B. Bacteroides, Peptostreptococcus, and Clostridium spp. C. Proteus spp. D. Enterococcus spp.

Which procedure is appropriate for culture of genital specimens in order to recover Chlamydia spp.? A. Inoculate cycloheximide-treated McCoy cells B. Plate onto blood and chocolate agar C. Inoculate into thioglycollate (THIO) broth D. Plate onto modified Thayer–Martin agar within 24 hours

Specimens for virus culture should be transported in media containing: A. Antibiotics and 5% sheep blood B. Saline and 5% sheep blood C. 22% bovine albumin D. Antibiotics and nutrient

Cerebrospinal fluid (CSF) should be cultured immediately, but if delayed the specimen should be: A. Refrigerated at 4°C to 6°C B. Frozen at –20°C C. Stored at room temperature for no longer than 24 hours D. Incubated at 37°C and cultured as soon as possible

The most sensitive method for the detection of β-lactamase in bacteria is by the use of: A. Chromogenic cephalosporin B. Penicillin C. Oxidase D. Chloramphenicol acetyltransferase

The breakpoint of an antimicrobial drug refers to: A. The amount needed to cause bacteriostasis B. A minimum inhibitory concentration (MIC) of 16 μg/mL or greater C. A MIC of 64 μg/mL or greater D. The level of drug that is achievable in serum

Which of the following variables may change the results of an MIC? A. Inoculum size B. Incubation time C. Growth rate of the bacteria D. All of these options

According to the Kirby–Bauer standard antimicrobial susceptibility testing method, what should be done when interpreting the zone size of a motile, swarming organism such as a Proteus species? A. The swarming area should be ignored B. The results of the disk diffusion method are invalid C. The swarming area should be measured as the growth boundary D. The isolate should be retested after diluting to a 0.05 McFarland standard

Which class of antibiotics is used for the treatment of serious gram-negative infections as well as infections with Mycobacterium tuberculosis? A. Cephalosporins B. Penicillins C. Tetracyclines D. Aminoglycosides

Select the medium best suited for the recovery of Yersinia enterocolitica from a patient with gastroenteritis. A. Hektoen agar B. Cefsulodin–Irgasan–Novobiocin (CIN) agar C. Blood agar D. Eosinmethylene blue agar

A suspected case of plague requires which of the following procedures in order to confirm Yersinia pestis? A. Collection of multiple sets of blood cultures B. Incubation of blood cultures at both 28°C and 35°C C. Culture aspirates from bubos to MacConkey agar at room temperature D. All of these options

SITUATION: Abdominal pain, fever, vomiting, and nausea prompted an elderly male to seek medical attention. A watery stool specimen producing no fecal leukocytes or erythrocytes was cultured and grew a predominance of gram-negative fermentative bacilli. The colonies were beta-hemolytic on blood agar and cream colored on MacConkey agar. The colonies were both oxidase and catalase positive. What is the most likely identification? A. Aeromonas hydrophilia B. Escherichia coli C. Salmonella spp. D. Shigella spp.

SITUATION: Several attendees of a medical conference in the Gulf coast area became ill after frequenting a seafood restaurant. A presumptive identification of Vibrio cholera was made after stool specimens from several subjects grew clear colonies on MacConkey agar and yellow colonies on TCBS agar. Which key tests would help eliminate Aeromonas and Plesiomonas spp.? A. Mannitol fermentation, Na+ requirement B. Oxidase, motility C. Oxidase, nitrate D. Hemolysis on blood agar, catalase

SITUATION: A group of elementary students became ill after eating undercooked ground beef prepared in the school cafeteria. The suspected pathogen, E. coli serotype 0157:H7, is usually recovered using which of the following media? A. XLD agar B. MacConkey agar C. MacConkey agar with sorbitol D. Hektoen agar

Biochemically, the Enterobacteriaceae are gram-negative rods that: A. Ferment glucose, reduce nitrate to nitrite, and are oxidase negative B. Ferment glucose, produce indophenol oxidase, and form gas C. Ferment lactose and reduce nitrite tocnitrogen gas D. Ferment lactose and produce indophenol oxidase

The ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating: A. Salmonella spp. from Pseudomonas spp. B. Shigella spp. from some strains of Escherichia coli C. Klebsiella spp. from Enterobacter spp. D. Proteus vulgaris from Salmonella spp.

The Voges–Proskauer (VP) test detects which end product of glucose fermentation? A. Acetoin B. Nitrite C. Acetic acid D. Hydrogen sulfide

At which pH does the methyl red (MR) test become positive? A. 7.0 B. 6.5 C. 6.0 D. 4.5

A positive Simmons citrate test is seen as a: A. Blue color in the medium after 24 hours of incubation at 35°C B. Red color in the medium after 18 hours of incubation at 35°C C. Yellow color in the medium after 24 hours of incubation at 35°C D. Green color in the medium after 18 hours of incubation at 35°C

In the test for urease production, ammonia reacts to form which product? A. Ammonium citrate B. Ammonium carbonate C. Ammonium oxalate D. Ammonium nitrate

Which of the following reagents is added to detect the production of indole? A. p-Dimethylaminobenzaldehyde B. Bromcresol purple C. Methyl red D. Cytochrome oxidase

Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: A. Ammonia B. Urea C. CO2 D. Amines

Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates: A. E. coli B. Citrobacter spp. C. Salmonella spp. D. Proteus spp.

Putrescine is an alkaline amine product of which bacterial enzyme? A. Arginine decarboxylase B. Phenylalanine deaminase C. Ornithine decarboxylase D. Lysine decarboxylase

Which genera are positive for phenylalanine deaminase? A. Enterobacter, Escherichia, and Salmonella B. Morganella, Providencia, and Proteus C. Klebsiella and Enterobacter D. Proteus, Escherichia, and Shigella

Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: A. Ratio of lactose to glucose B. Ability to detect H2S production C. Use of sucrose in the medium D. Color reaction denoting production of acid

The malonate test is most useful in differentiating which members of the Enterobacteriaceae? A. Shigella B. Proteus C. Salmonella subgroups 2, 3 (the former Arizona) D. Serratia

Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens? A. Enterobacter, Klebsiella, Providencia, and Proteus B. Escherichia, Salmonella, Shigella, and Yersinia C. Pseudomonas, Moraxella, Acinetobacter, and Aeromonas D. Enterobacter, Citrobacter, and Morganella

An isolate of E. coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping? A. Sorbitol (fermentation) B. Mannitol (oxidation) C. Raffinose (fermentation) D. Sucrose (fermentation)

Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with: A. E. coli B. Salmonella spp. C. Pseudomonas spp. D. Proteus spp.

Which species of Shigella is most commonly associated with diarrheal disease in the United States? A. S. dysenteriae B. S. flexneri C. S. boydii D. S. sonnei

Which of the following tests best differentiates Shigella species from E. coli? A. Hydrogen sulfide, VP, citrate, and urease B. Lactose, indole, ONPG, and motility C. Hydrogen sulfide, MR, citrate, and urease D. Gas, citrate, and VP

Which genera of Enterobacteriaceae are usually nonmotile at 36°C? A. Shigella, Klebsiella, and Yersinia B. Escherichia, Edwardsiella, and Enterobacter C. Proteus, Providencia, and Salmonella D. Serratia, Morganella, and Hafnia

Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2–3 days before is characteristic of shigellosis but may also result from infection with: A. Campylobacter spp. B. Salmonella spp. C. Proteus spp. D. Yersinia spp.

Cold enrichment of feces (incubation at 4°C) in phosphate-buffered saline prior to subculture onto enteric media enhances the recovery of: A. Enterotoxigenic E. coli B. Salmonella paratyphi C. Hafnia alvei D. Y. enterocolitica

Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of the Enterobacteriaceae? A. MR and VP, urease, and blood agar plate B. Phenylalanine deaminase, urease, and CDC agar plate C. Bacitracin, β-lactamase, and MacConkey agar plate D. Indole, oxidase, MacConkey, and blood agar plates

A routine, complete stool culture procedure should include media for the isolation of E. coli O157:H7 as well as: A. Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus B. Vibrio cholerae, Brucella, and Yersinia spp. C. S. aureus, group B streptococci, and group D streptococci D. Clostridium difficile, Clostridium perfringens, and Yersinia spp.

Which group of tests best identifies the Morganella and Proteus genera? A. Motility, urease, and phenylalanine deaminase B. Malonate, glucose fermentation, and deoxyribonuclease (DNase) C. Indole, oxidase, MR, and VP D. Indole, citrate, and urease

Which group of tests best differentiates Enterobacter aerogenes from Edwardsiella tarda? A. Motility, citrate, and urease B. Hydrogen sulfide (H2S) production, sucrose fermentation, indole, and VP C. Lysine decarboxylase, urease, and arginine dihydrolase D. Motility, H2S production, and DNase

Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics? A. Yellow pigmentation and negative sorbitol fermentation B. Pink pigmentation and positive arginine dihydrolase C. Yellow pigmentation and positive urease D. H2S production on TSI

Members of the genus Cedecea are best differentiated from Serratia spp. by which test result? A. Positive motility B. Positive urease C. Positive phenylalanine deaminase D. Negative DNase

Which of the following organisms is often confused with the Salmonella species biochemically and on plated media? A. E. coli B. Citrobacter freundii C. Enterobacter cloacae D. Shigella dysenteriae

A gram-negative rod is recovered from a catheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanine deaminase and negative for H2S. The most probable identification is: A. Edwardsiella spp. B. Morganella spp. C. Ewingella spp. D. Shigella spp.

Which single test best separates Klebsiella oxytoca from K. pneumoniae? A. Urease B. Sucrose C. Citrate D. Indole

Which of the following organisms, found in normal fecal flora, may be mistaken biochemically for the genus Yersinia? A. Klebsiella spp. B. Proteus spp. C. E. coli D. Enterobacter spp.

Why might it be necessary for both pink (lactose-positive) and colorless (lactose-negative) colonies from an initial stool culture on MacConkey agar to be subcultured and tested further for possible pathogens? A. Most Shigella strains are lactose positive B. Most Salmonella strains are maltose negative C. Most Proteus spp. are lactose negative D. Pathogenic E. coli can be lactose positive or lactose negative

Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains from stool specimens? A. Salmonella–Shigella agar B. Hektoen enteric agar C. MacConkey agar D. CNA agar

Which organism is sometimes mistaken for Salmonella and will agglutinate in Salmonella polyvalent antiserum? A. C. freundii strains B. Proteus mirabilis strains C. S. sonnei strains D. E. coli

A bloody stool cultured from a 26-year-old woman after 3 days of severe diarrhea showed the following results at 48 hours after being plated on the following media: MacConkey agar: little normal flora with many non–lactose-fermenting colonies Hektoen enteric agar: many blue-green colonies Campylobacter blood agar and C. difficile agar: no growth Clear colonies (from MacConkey agar) tested negative for oxidase, indole, urease, motility, and H2S The most likely identification is: A. Shigella spp. B. Salmonella spp. C. Proteus spp. D. E. coli

Which of the following organisms are generally positive for β-galactosidase? A. Salmonella spp. B. Shigella spp. C. Proteus spp. D. E. coli

In the Kauffmann–White schema, the combined antigens used for serological identification of the Salmonella spp. are: A. O antigens B. H antigens C. Vi and H antigens D. O, Vi, and H antigens

The drugs of choice for treatment of infections with Enterobacteriaceae are: A. Aminoglycosides, trimethoprim–sulfamethoxazole, third-generation cephalosporins B. Ampicillin and nalidixic acid C. Streptomycin and isoniazid D. Chloramphenicol, ampicillin, and colistin

The Shiga-like toxin (verotoxin) is produced mainly by which Enterobacteriaceae? A. Klebsiella pneumoniae B. E. coli C. Salmonella typhimurium D. Enterobacter cloacae

Infections caused by Yersinia pestis are rare in the United States. Those cases that do occur are most frequently located in which region? A. New Mexico, Arizona, and California B. Alaska, Oregon, and Utah C. North and South Carolina and Virginia D. Ohio, Michigan, and Indiana

A leg culture from a nursing home patient grew gram-negative rods on MacConkey agar as pink to dark pink oxidase-negative colonies. Given the following results, which is the most likely organism? TSI = A/A VP = + Urease = + Indole = Neg Citrate = + Motility = Neg MR = Neg H2S = Neg H2S (TSI) = Neg MR = Neg DNase = + Urease = Neg Antibiotic susceptibility: resistant to carbenicillin and ampicillin A. Serratia marcescens B. Proteus vulgaris C. Enterobacter cloacae D. Klebsiella pneumoniae

A leg-wound culture from a hospitalized 70-year-old diabetic man grew motile, lactose-negative colonies on MacConkey agar. Given the following biochemical reactions at 24 hours, what is the most probable organism? H2S (TSI) = Neg MR = Neg DNase = + Urease = Neg Phenylalanine deaminase = Neg Ornithine and lysine decarboxylase = + Arginine decarboxylase = Neg Gelatin hydrolysis = + A. Proteus vulgaris B. Serratia marcescens C. Proteus mirabilis D. Enterobacter cloacae

Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization also showed gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism? TSI = A/A gas VP = Neg H2S = Neg Urease = Neg Phenylalanine deaminase = Neg Indole = + MR = + Citrate = Neg Lysine decarboxylase = + A. Proteus vulgaris B. Salmonella typhi C. Yersinia enterocolitica D. E. coli

A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: MacConkey agar = clear colonies; XLD agar = clear colonies; Hektoen agar = green colonies; Salmonella–Shigella agar = small, clear colonies Which tests are most appropriate for identification of this enteric pathogen? A. TSI, motility, indole, urease, Shigella typing with polyvalent sera B. TSI, motility, indole, lysine, Salmonella typing with polyvalent sera C. TSI, indole, MR, VP, citrate D. TSI, indole, MR, and urease

Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? H2S (TSI) = + VP = Neg DNase = + Gelatin hydrolysis = + Ornithine decarboxylase = Neg Indole = + Citrate = Neg Phenylalanine deaminase = + MR = + Urease = + A. Proteus vulgaris B. Proteus mirabilis C. Serratia marcescens D. Klebsiella pneumoniae

Three consecutive stool cultures from a 25-year-old male patient produced scant normal fecal flora on MacConkey and Hektoen agars. However, colonies on CIN agar (cefsulodin–irgasan–novobiocin) displayed “bulls-eye” colonies after 48 hours incubation. The patient had been suffering from enterocolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram-negative rod? A. E. coli B. Proteus mirabilis C. Yersinia enterocolitica D. Klebsiella pneumoniae

A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 3 days earlier. Which pathogen is most likely responsible for the following results? Growth on: XLD agar = yellow colonies HE agar = yellow colonies Mac agar = light pink and dark pink colonies Mac with sorbitol agar – few dark pink and many colorless colonies A. Salmonella spp. B. Shigella spp. C. E. coli O157:H7 D. Yersinia enterocolitica

Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling “closed safety pins.” The organism grew on MacConkey’s agar showing non–lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification? A. Yersinia pestis B. Klebsiella pneumoniae C. Proteus vulgaris D. Morganella morganii

The majority of clinical laboratories with a microbiology department should have the capability of serotyping which pathogenic Enterobacteriaceae? A. Yersinia enterocolitica, Shigella spp. B. E. coli O157:H7, Salmonella spp., Shigella spp. C. Yersinia pestis, Salmonella spp. D. Edwardsiella spp., Salmonella spp.

Direct spread of pneumonic plague disease occurs by which route? A. Fecal–oral route B. Rat bite C. Ingestion of contaminated tissue D. Inhalation of contaminated airborne droplets

Which isolates of the Enterobacteriaceae family most commonly produce extended-spectrum β-lactamase (ESBL)? A. E. coli and Klebsiella pneumoniae B. Yersinia enterocolitica and Yersinia pestis C. Morganella morganii and Proteus vulgaris D. Salmonella typhi and Shigella sonnei

What are the most appropriate screening tests to presumptively differentiate and identify the nonfermentative gram-negative bacilli (NFB) from the Enterobacteriaceae? A. Catalase, decarboxylation of arginine, growth on blood agar B. Motility, urease, morphology on blood agar C. Oxidase, TSI, nitrate reduction, growth on MacConkey agar D. Oxidase, indole, and growth on blood agar

Presumptive tests used for identification of the Pseudomonas spp. are: A. Oxidase, oxidation–fermentation (OF) glucose (open), OF glucose (sealed), motility, pigment production B. Growth on blood agar plate (BAP) and eosin–methylene blue (EMB) agars, lysine decarboxylation, catalase C. Growth on MacConkey, EMB, and XLD agars and motility D. Growth on mannitol salt agar and flagellar stain

Which tests are most appropriate to differentiate between Pseudomonas aeruginosa and Pseudomonas putida? A. Oxidase, motility, pyoverdin B. Oxidase, motility, lactose C. Oxidase, ONPG, DNase D. Mannitol, nitrate reduction, growth at 42°C

Which test group best differentiates Acinetobacter baumannii from P. aeruginosa? A. Oxidase, motility, NO3 reduction B. MacConkey growth, 37°C growth, catalase C. Blood agar growth, oxidase, catalase D. Oxidase, TSI, MacConkey growth

In addition to motility, which test best differentiates Acinetobacter spp. and Alcaligenes spp.? A. TSI B. Oxidase C. Catalase D. Flagellar stain

The most noted differences between P. aeruginosa and Stenotrophomonas maltophilia are: A. Oxidase, catalase, and TSI B. Oxidase, catalase, and ONPG C. Oxidase, 42°C growth, and polar tuft of flagella D. Catalase, TSI, and pigment

Which Pseudomonas is usually associated with a lung infection related to cystic fibrosis? A. P. fluorescens B. P. aeruginosa C. P. putida D. Burkholderia pseudomallei

A nonfermenter recovered from an eye wound is oxidase positive, motile with polar monotrichous flagella, and grows at 42°C. Colonies are dry, wrinkled or smooth, buff to light brown in color, and are difficult to remove from the agar. In which DNA homology group should this organism be placed? A. Pseudomonas stutzeri B. Pseudomonas fluorescens C. Pseudomonas alcaligenes D. Pseudomonas diminuta

Which organism is associated with immunodeficiency syndromes and melioidosis (a glanders-like disease in Southeast Asia and northern Australia)? A. Pseudomonas aeruginosa B. Pseudomonas stutzeri C. Pseudomonas putida D. Burkholderia pseudomallei

Which biochemical tests are needed to differentiate Burkholderia cepacia from S. maltophilia? A. Pigment on blood agar, oxidase, DNase B. Pigment on MacConkey agar, flagellar stain, motility C. Glucose, maltose, lysine decarboxylase D. TSI, motility, oxidase

Alcaligenes faecalis (formerly A. odorans) is distinguished from Bordetella bronchiseptica with which test? A. Urease (rapid) B. Oxidase C. Growth on MacConkey agar D. Motility

Chryseobacterium spp. are easily distinguished from Acinetobacter spp. by which of the following two tests? A. Oxidase, growth on MacConkey agar B. Oxidase and OF (glucose) C. TSI and urea hydrolysis D. TSI and VP

The following results were obtained from a pure culture of gram-negative rods recovered from the pulmonary secretions of a 10-year-old cystic fibrosis patient with pneumonia: Oxidase = + Glucose OF (open) = + Pigment = Red (nonfluorescent) Growth at 42°C = + Motility = + Gelatin hydrolysis = + Arginine dihydrolase = + Flagella = + (polar, monotrichous) Which is the most likely organism? A. Burkholderia pseudomallei B. Pseudomonas stutzeri C. Burkholderia cepacia D. Pseudomonas aeruginosa

A gram-negative coccobacillus was recovered on chocolate agar from the CSF of an immunosuppressed patient. The organism was nonmotile and positive for indophenol oxidase but failed to grow on MacConkey agar. The organism was highly susceptible to penicillin. The most probable identification is: A. Acinetobacter spp. B. Pseudomonas aeruginosa C. Pseudomonas stutzeri D. Moraxella lacunata

Cetrimide agar is used as a selective isolation agar for which organism? A. Acinetobacter spp. B. Pseudomonas aeruginosa C. Moraxella spp. D. Stenotrophomonas maltophilia

A yellow pigment–producing organism that is oxidase positive, nonmotile, and does not grow on MacConkey agar is: A. Acinetobacter baumannii B. Acinetobacter lwoffii C. Burkholderia cepacia D. Chryseobacterium meningosepticum

Which reagent(s) is (are) used to develop the red color indicative of a positive reaction in the nitrate reduction test? A. Sulfanilic acid and α-naphthylamine B. Ehrlich’s and Kovac’s reagents C. o-Nitrophenyl-β-D-galactopyranoside D. Kovac’s reagent

Chryseobacterium spp. and B. cepacia are easily differentiated by which test? A. Motility B. OF glucose C. Oxidase D. Cetrimide agar

A 15-year-old female complained of a severe eye irritation after removing her soft-contact lenses. A swab of the infected right eye was obtained by an ophthalmologist, who ordered a culture and sensitivity test. The culture was plated on blood agar and MacConkey agar. At 24 hours, growth of a gram-negative rod that tested positive for cytochrome oxidase was noted. The Mueller–Hinton sensitivity plate showed a bluish-green “lawn” of growth that proved highly resistant to most of the antibiotics tested except amikacin, tobramycin, and ciprofloxacin. What is the most likely identification? A. Burkholderia cepacia B. Pseudomonas aeruginosa C. Stenotrophomonas maltophilia D. Acinetobacter baumannii

Which of the listed Pseudomonas spp. is associated with the following virulence factors: exotoxin A, endotoxins, proteolytic enzymes, antimicrobial resistance, and production of alginate? A. P. fluorescens B. P. putida C. P. stutzeri D. P. aeruginosa

A 20-year-old horse groomer exhibited a “glanders-like” infection. His history indicated he had suffered several open wounds on his hands 2 weeks before the swelling of his lymph nodes. A gram-negative rod was recovered from a blood culture that grew well on blood and MacConkey agars. Most of the biochemical tests were negative, including the cytochrome oxidase test. What is the most likely identification? A. Burkholderia mallei B. Pseudomonas aeruginosa C. Pseudomonas stutzeri D. Burkholderia pseudomallei

A Vietnam War veteran presented with a “glanders-like” infection (melioidosis). Several blood cultures produced gram-negative rods that were positive for cytochrome oxidase, oxidized glucose and xylose, and grew at 42°C. What is the most likely organism? A. Stenotrophomonas maltophilia B. Burkholderia pseudomallei C. Pseudomonas aeruginosa D. Acinetobacter spp.

Cytochrome oxidase-positive, nonfermentative gram-negative bacilli were recovered from the stool of a cystic fibrosis (CF) patient. The isolates produced wet (mucoidy) colonies on blood agar. Which identification is most likely? A. Acinetobacter spp. B. Pseudomonas alcaligenes C. Pseudomonas stutzeri D. Pseudomonas aeruginosa

A visitor to South America who returned with diarrhea is suspected of being infected with V. cholerae. Select the best medium for recovery and identification of this organism. A. MacConkey agar B. Blood agar C. TCBS agar D. XLD agar

A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered from a stool culture. Given the following results, what is the most likely identification? Lysine decarboxylase = + Indole = + VP = Neg Urease = ± Arginine decarboxylase = Neg KIA = Alk/Acid Lactose = Neg String test = Neg A. Vibrio cholerae B. Vibrio parahaemolyticus C. Shigella spp. D. Salmonella spp.

A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results: Catalase = + Motility = + Growth at 42°C = + Grape odor = Neg Oxidase = + Hippurate hydrolysis = + Nalidixic acid = Susceptible Pigment = Neg Cephalothin = Resistant The most likely identification is: A. Pseudomonas aeruginosa B. Campylobacter jejuni C. Campylobacter fetus D. Pseudomonas putida

Which atmospheric condition is needed to recover Campylobacter spp. from specimens inoculated onto a Campy-selective agar at 35°C–37°C and 42°C? A. 5% O2, 10% CO2, and 85% N2 B. 20% O2, 10% CO2, and 70% N2 C. 20% O2, 20% CO2, and 60% N2 D. 20% O2, 5% CO2, and 75% N2

Which group of tests best differentiates Helicobacter pylori from C. jejuni? A. Catalase, oxidase, and Gram stain B. Catalase, oxidase, and nalidixic acid sensitivity C. Catalase, oxidase, and cephalothin sensitivity D. Urease, nitrate, and hippurate hydrolysis

Which of the following tests should be done first in order to differentiate Aeromonas spp. from the Enterobacteriaceae? A. Urease B. OF glucose C. Oxidase D. Catalase

Which is the best rapid test to differentiate Plesiomonas shigelloides from a Shigella species on selective enteric agar? A. Oxidase B. Indole C. TSI D. Urease

Which are the best two tests to differentiate A. hydrophilia from P. shigelloides? A. Oxidase and motility B. DNase and VP C. Indole and lysine decarboxylase D. Growth on MacConkey and blood agar

Which genus (in which most species are oxidase and catalase positive) of small gram-negative coccobacilli is associated mainly with animals but may cause endocarditis, bacteremia, as well as wound and dental infections in humans? A. Actinobacillus B. Pseudomonas C. Campylobacter D. Vibrio

Which of the following tests may be used to differentiate Cardiobacterium hominis from Actinobacillus spp.? A. Gram stain B. Indole C. Anaerobic incubation D. Oxidase

A mixture of slender gram-negative rods and coccobacilli with rounded ends was recovered from blood cultures following a patient’s root canal surgery. Given the following results after 48 hours, what is the most likely organism? Catalase = Neg Urease = Neg Oxidase = + Indole = Neg Ornithine decarboxylase = + Lysine decarboxylase = + X and V requirement = Neg Carbohydrates = Neg (no acid produced) Growth on blood and chocolate agar = + (with pitting of agar) Growth on MacConkey agar = Neg A. Eikenella corrodens B. Actinobacillus spp. C. Cardiobacterium hominis D. Proteus spp.

Kingella kingae can best be differentiated from Eikenella corrodens using which medium? A. Sheep blood agar B. Chocolate agar C. MacConkey agar D. XLD agar

Kingella kingae is usually associated with which type of infection? A. Middle ear B. Endocarditis C. Meningitis D. Urogenital

Cultures obtained from a dog bite wound produced yellow, tan, and slightly pink colonies on blood and chocolate agar with a margin of fingerlike projections appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism? Oxidase = + Growth on MacConkey agar = Neg Catalase = + Motility = Neg A. Actinobacillus spp. B. Eikenella spp. C. Capnocytophaga spp. D. Pseudomonas

Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood and chocolate agar but fail to grow on MacConkey agar. The organisms are gram-negative pleomorphic rods that are both catalase and oxidase positive and strongly indole positive. The most likely organism is: A. Capnocytophaga spp. B. Pasteurella spp. C. Proteus spp. D. Pseudomonas spp.

Which media should be used to recover Bordetella pertussis from a nasopharyngeal specimen? A. Chocolate agar B. Blood agar C. MacConkey agar D. Bordet–Gengou agar

Which medium is recommended for the recovery of Brucella spp. from blood and bone marrow specimens? A. Biphasic Castenada bottles with Brucella broth B. Blood culture bottles with Brucella broth C. Bordet–Gengou agar plates and THIO broth D. Blood culture bottles with THIO broth

In addition to CO2 requirements and biochemical characteristics, Brucella melitensis and Brucella abortus are differentiated by growth on media containing which two dyes? A. Basic fuchsin and thionin B. Methylene blue and crystal violet C. Carbol fuchsin and iodine D. Safranin and methylene blue

Which of the following amino acids are required for growth of Francisella tularensis? A. Leucine and ornithine B. Arginine and lysine C. Cysteine and cystine D. Histidine and tryptophan

Which medium is best for recovery of Legionella pneumophila from clinical specimens? A. Chocolate agar B. Bordet–Gengou agar C. New yeast extract agar D. Buffered charcoal–yeast extract (CYE) agar

Haemophilus influenzae causes ocular infections (pinkeye) and requires X and V factors in the medium for growth. The subspecies Haemophilus influenza (biogroup) aegyptius can further be identified and differentiated by which two tests? A. Indole and xylose B. Glucose and urease C. Oxidase and catalase D. ALA test and oxidase

Haemophilus species that require the V factor (NAD) are easily recovered on which primary agar plate? A. Blood agar made with sheep red cells B. Blood agar made with horse red cells C. Chocolate agar D. Xylose agar

Which of the following products is responsible for satellite growth of Haemophilus spp. around colonies of Staphylococcus and Neisseria spp. on sheep blood agar? A. NAD B. Hemin C. Indole D. Oxidase

Which of the following products is responsible for satellite growth of Haemophilus spp. around colonies of Staphylococcus and Neisseria spp. on sheep blood agar? A. NAD B. Hemin C. Indole D. Oxida se

The majority of Haemophilus influenzae infections are caused by which of the following capsular serotypes? A. a B. b C. c D. d

Which Haemophilus species is generally associated with endocarditis? A. H. influenzae B. H. ducreyi C. H. aphrophilus D. H. haemolyticus

Which Haemophilus species is difficult to isolate and recover from genital ulcers and swollen lymph nodes? A. H. aphrophilus B. H. ducreyi C. H. haemolyticus D. H. parahaemolyticus

Which of the following is a characteristic of strains of Haemophilus influenzae that are resistant to ampicillin? A. Production of β-lactamase enzymes B. Hydrolysis of chloramphenicol C. Hydrolysis of urea D. All of these options

The δ-ALA test (for porphyrins) is a confirmatory procedure for which test used for identification of Haemophilus species? A. X factor requirement B. V factor requirement C. Urease production D. Indole production

An elderly woman who cared for several domestic cats was hospitalized with suspected cat-scratch disease (CSD). Blood cultures appeared negative, but a small, slightly curved pleomorphic gram-negative bacillus grew on BHI agar (brain, heart infusion agar with 5% horse or rabbit blood). What is the most likely identification? A. Bartonella spp. B. Brucella spp. C. Kingella spp. D. Haemophilus spp.

A 5-year-old nonimmunized male with a persistent cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet–Genjou, and Regan–Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? A. Haemophilus influenza B. Bordetella pertussis C. Haemophilus parainfluenzae D. Bordetella bronchiseptica

A 29-year-old male who often hunted rabbits and spent a lot of time in the woods was admitted to the hospital with skin ulcers on his upper extremities. At 48 hours, a small coccobacillus was recovered from the aerobic blood culture bottle only. The organism stained poorly with Gram stain, but did stain with acridine orange. Cultures taken from the ulcers did not grow on primary media. What is the most likely identification? A. Pseudomonas aeruginosa B. Pseudomonas fluorescens C. Chryseobacterium spp. D. Francisella tularensis

A neonate was readmitted to the hospital with a diagnosis of meningitis. The CSF revealed gram-negative straight rods. At 24 hours, the organism grew on 5% sheep blood and chocolate agars displaying a yellow pigment. On MacConkey agar, it appeared as a non–lactose fermenter. Colonies were oxidase, DNase, and gelatinase positive, and oxidized glucose and mannitol. What is the most likely identification? A. Haemophilus influenza B. Chryseobacterium meningosepticum C. Stenotrophomonas maltophilia D. Acinetobacter baumannii

A 46-year-old dog warden was admitted to the hospital with several puncture bite wounds encountered while wrangling with a stray dog. Culture at 48 hours produced small yellow colonies on 5% sheep blood and chocolate agars in 10% CO2, but no growth on MacConkey agar. Gram stain showed gram-negative curved, fusiform rods. Colonies were oxidase and catalase positive. What is the most likely identification? A. Capnocytophaga canimorsus B. Francisella tularensis C. Legionella pneumophila D. Pseudomonas aeruginosa

The HACEK group of organisms (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.) are all known for which type of infection? A. Urinary tract B. Endocarditis C. Pharyngitis D. Tonsillitis

A suspected case of Legionnaires’ disease was noted on the request form for a culture and sensitivity ordered on a sputum sample. The patient was a 70-year-old male who presented with a positive serological test for Legionella spp. What is the most efficient way to confirm the infection using the submitted sample? A. Culture the sputum on MacConkey agar B. Gram stain of the sputum C. Acid-fast staining D. Direct immunofluorescent microscopy

The test used most often to separate the Micrococcaceae family from the Streptococcaceae family is: A. Bacitracin B. Catalase C. Hemolysis pattern D. All of these options

The test used most often to separate the Micrococcaceae family from the Streptococcaceae family is: A. Bacitracin B. Catalase C. Hemolysis pattern D. All of these optio ns

Lysostaphin is used to differentiate Staphylococcus from which other genus? A. Streptococcus B. Stomatococcus C. Micrococcus D. Planococcus

Which of the following tests is used routinely to identify Staphylococcus aureus? A. Slide coagulase test B. Tube coagulase test C. Latex agglutination D. All of these options

Which of the following enzymes contribute to the virulence of S. aureus? A. Urease and lecithinase B. Hyaluronidase and β-lactamase C. Lecithinase and catalase D. Cytochrome oxidase

Toxic shock syndrome is attributed to infection with: A. Staphylococcus epidermidis B. Staphylococcus hominis C. Staphylococcus aureus D. Staphylococcus saprophyticus

Which Staphylococcus species, in addition to S. aureus, also produces coagulase? A. S. intermedius B. S. saprophyticus C. S. hominis D. All of these options

Staphylococcus epidermidis (coagulase negative) is recovered from which of the following sources? A. Prosthetic heart valves B. Intravenous catheters C. Urinary tract D. All of these options

Slime production is associated with which Staphylococcus species? A. S. aureus B. S. epidermidis C. S. intermedius D. S. saprophyticus

Strains of Staphylococcus species resistant to the β-lactam antibiotics by standardized disk diffusion and broth microdilution susceptibility methods are called: A. Heteroresistant B. Bacteriophage group 52A C. Cross resistant D. Plasmid altered

Staphylococcus saprophyticus is best differentiated from Staphylococcus epidermidis by resistance to: A. 5 μg of lysostaphin B. 5 μg of novobiocin C. 10 units of penicillin D. 0.04 unit of bacitracin

Coagulase at 4 hours = + DNase = + Hemolysis on blood agar = β Coagulase at 18 hours = Neg Novobiocin = Sensitive (16-mm zone) Mannitol salt plate = + (acid production) What is the most probable identification? A. Staphylococcus saprophyticus B. Staphylococcus epidermidis C. Staphylococcus aureus D. Staphylococcus hominis

Staphylococcus aureus recovered from a wound culture gave the following antibiotic sensitivity pattern by the standardized Kirby–Bauer method (S = sensitive; R = resistant): Penicillin = R Cephalothin = R Vancomycin = S Ampicillin = S Cefoxitin = R Methicillin = R Which is the drug of choice for treating this infection? A. Penicillin B. Ampicillin C. Cephalothin D. Vancomycin

Which of the following tests should be used to differentiate Staphylococcus aureus from Staphylococcus intermedius? A. Acetoin B. Catalase C. Slide coagulase test D. Urease

A gram-positive coccus recovered from a wound ulcer from a 31-year-old diabetic patient showed pale yellow, creamy, β-hemolytic colonies on blood agar. Given the following test results, what is the most likely identification? Catalase = + Glucose OF: positive open tube, negative sealed tube Mannitol salt = Neg Slide coagulase = Neg A. Staphylococcus aureus B. Staphylococcus epidermidis C. Micrococcus spp. D. Streptococcus spp.

Urine cultured from the catheter of an 18-year-old female patient produced more than 100,000 col/mL on a CNA plate. Colonies were catalase positive, coagulase negative by the latex agglutination slide method as well as the tube coagulase test. The best single test for identification is: A. Lactose fermentation B. Urease C. Catalase D. Novobiocin susceptibility

A Staphylococcus spp. recovered from a wound (cellulitis) was negative for the slide coagulase test (clumping factor) and negative for novobiocin resistance. The next test(s) needed for identification is (are): A. Tube coagulase test B. β-Hemolysis on blood agar C. Mannitol salt agar plate D. All of these options

Furazolidone (Furoxone) susceptibility is a test used to differentiate: A. Staphylococcus spp. from Micrococcus spp. B. Streptococcus spp. from Staphylococcus spp. C. Staphylococcus spp. from Pseudomonas spp. D. Streptococcus spp. from Micrococcus spp.

Bacitracin resistance (0.04 unit) is used to differentiate: A. Micrococcus spp. from Staphylococcus spp. B. Staphylococcus spp. from Neisseria spp. C. Planococcus spp. from Micrococcus spp. D. Staphylococcus spp. from Streptococcus spp.

Which of the following tests will rapidly differentiate micrococci from staphylococci? A. Catalase B. Coagulase C. Modified oxidase D. Novobiocin susceptibility

Streptococcus species exhibit which of the following properties? A. Aerobic, oxidase positive, and catalase positive B. Facultative anaerobe, oxidase negative, catalase negative C. Facultative anaerobe, β-hemolytic, catalase positive D. May be α-, β-, or γ-hemolytic, catalase positive

Which group of streptococci is associated with erythrogenic toxin production? A. Group A B. Group B C. Group C D. Group G

A fourfold rise in titer of which antibody is the best indicator of a recent infection with group A β-hemolytic streptococci? A. Anti-streptolysin O B. Anti-streptolysin S C. Anti-A D. Anti-B

Bacitracin A disks (0.04 unit) are used for the presumptive identification of which group of β-hemolytic streptococci? A. Group A B. Group B C. Group C D. Group F

Trimethoprim–sulfamethoxazole (SXT) disks are used along with bacitracin disks to differentiate which streptococci? A. α-Hemolytic streptococci B. β-Hemolytic streptococci C. Streptococcus pneumoniae D. Enterococcus faecalis

A false-positive CAMP test for the presumptive identification of group B streptococci may occur if the plate is incubated in a(n): A. Candle jar or CO2 incubator B. Ambient air incubator C. 35°C incubator D. 37°C incubator

Which test is used to differentiate the viridans streptococci from the group D streptococci and enterococci? A. Bacitracin disk test B. CAMP test C. Hippurate hydrolysis test D. Bile esculin test

S. pneumoniae and the viridans streptococci can be differentiated by which test? A. Optochin disk test, 5 μg/mL or less B. Bacitracin disk test, 0.04 unit C. CAMP test D. Bile esculin test

The bile solubility test causes the lysis of: A. Streptococcus bovis colonies on a blood agar plate B. Streptococcus pneumoniae colonies on a blood agar plate C. Group A streptococci in broth culture D. Group B streptococci in broth culture

The salt tolerance test (6.5% salt broth) is used to presumptively identify: A. Streptococcus pneumoniae B. Streptococcus bovis C. Streptococcus equinus D. Enterococcus faecalis

In addition to Enterococcus faecalis, which other streptococci will grow in 6.5% salt broth? A. Group A streptococci B. Group B streptococci C. Streptococcus pneumoniae D. Group D streptococci (nonenterococci)

The quellung test is used to identify which Streptococcus species? A. S. pyogenes B. S. agalactiae C. S. sanguis D. S. pneumoniae

The L-pyrrolidonyl-β-napthylamide (PYR) hydrolysis test is a presumptive test for which streptococci? A. Group A and D (enterococcus) streptococci B. Group A and B β-hemolytic streptococci C. Nongroup A or B β-hemolytic streptococci D. Streptococcus pneumoniae and group D streptococci (nonenterococcus)

CAMP test = Neg Bile esculin = Neg PYR = Neg Optochin = Resistant Hippurate hydrolysis = Neg 6.5% salt = Neg Bacitracin = Resistant SXT = Sensitive The most likely identification is: A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci

β-Hemolytic streptococci, more than 50,000 col/mL, were isolated from a urinary tract catheter urine specimen. Given the following reactions, what is the most likely identification? CAMP test = Neg Bile solubility = Neg PYR = + SXT = Resistant Optochin = Resistant Hippurate hydrolysis = ± 6.5% salt = + Bile esculin = + Bacitracin = Resistant A. Group A streptococci B. Group B streptococci C. Enterococcus faecalis D. Nongroup A, nongroup B, nongroup D streptococci

Nutritionally variant streptococci (NVS) require specific thiol compounds, cysteine, or the active form of vitamin B6. Which of the following tests supplies these requirements? A. CAMP test B. Bacitracin susceptibility test C. Bile solubility test D. Staphylococcal cross-streak test

Which two tests best differentiate S. bovis (group D, nonenterococcus) from Streptococcus salivarius? A. Bile esculin and 6.5% salt broth B. Starch hydrolysis and acid production from mannitol C. Bacitracin and PYR D. Trimethoprim–sulfamethoxazole susceptibility and PYR

MTM medium is used primarily for the selective recovery of which organism from genital specimens? A. Neisseria gonorrhoeae B. Neisseria lactamica C. Neisseria sicca D. Neisseria flavescens

Variation in colony types seen with fresh isolates of Neisseria gonorrhoeae and sometimes with Neisseria meningitidis are the result of: A. Multiple nutritional requirements B. Pili on the cell surface C. Use of a transparent medium D. All of these options

Gram-negative diplococci recovered from an MTM plate and giving a positive oxidase test can be presumptively identified as: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Neisseria lactamica D. All of these options

The Superoxol test is used as a rapid presumptive test for: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Neisseria lactamica D. Moraxella (Branhamella) catarrhalis

Nonpathogenic Moraxella spp. capable of growing on selective media for Neisseria can be differentiated from Neisseria spp. by which test? A. Catalase test B. 10-unit penicillin disk C. Oxidase test D. Superoxol test

A Gram stain of a urethral discharge from a man showing extracellular and intracellular gram-negative diplococci within segmented neutrophils is a presumptive identification for: A. Neisseria gonorrhoeae B. Neisseria meningitidis C. Moraxella (Branhamella) catarrhalis D. Neisseria lactamica

The β-galactosidase test aids in the identification of which Neisseria species? A. N. lactamica B. N. meningitidis C. N. gonorrhoeae D. N. flavescens

Cystine tryptic digest (CTA) media used for identification of Neisseria spp. should be inoculated and cultured in: A. A CO2 incubator at 35°C for 24 hours B. A CO2 incubator at 42°C for up to 72 hours C. A nonCO2 incubator at 35°C for up to 72 hours D. An anaerobic incubator at 35°C for up to 72 hours

Resistance to which drug categorizes a strain of Staphylococcus aureus as methicillin-resistant Staphylococcus aureus (MRSA)? A. Oxacillin B. Colistin C. Trimethoprim–sulfamethoxazole D. Tetracycline

An oxacillin-disk screen test is used to detect Streptococcus pneumonia resistance to penicillin. Using Mueller–Hinton agar with 5% sheep blood and a 1 μg oxacillin disk, what is the recommended inhibition zone size for penicillin susceptibility? A. ≥5 mm B. ≥10 mm C. ≥15 mm D. ≥20 mm

Culture on MTM media of a vaginal swab produced several colonies of gram-negative diplococci that were catalase and oxidase positive and Superoxol negative. Given the following carbohydrate reactions, select the most likely identification. Glucose = + Maltose = + Sucrose = Neg Fructose = Neg Lactose = + A. Neisseria gonorrhoeae B. Neisseria sicca C. Neisseria flavescens D. Neisseria lactamica

Sputum from a patient with pneumonia produced many colonies of gram-negative diplococci on a chocolate plate that were also present in fewer numbers on MTM after 48 hours. Given the following results, what is the most likely identification? Catalase = + DNase = + Glucose = Neg Lactose = Neg Fructose = Neg Oxidase = + Tributyrin hydrolysis = + Sucrose = Neg Maltose = Neg A. Moraxella catarrhalis B. Neisseria flavescens C. Neisseria sicca D. Neisseria elongata

Which one of the following organisms is a known producer of β-lactamase–producing strains, and should be tested (screened) by a commercial β-lactamase assay prior to susceptibility testing? A. Streptococcus pneumoniae B. Group B streptococci C. Enterococcus spp. D. Planococcus spp.

Which test is used for the determination of inducible clindamycin resistance in staphylococci and streptococci? A. E-test B. D-zone test C. A-test D. Camp test

Large gram-positive spore-forming rods growing on blood agar as large, raised, β-hemolytic colonies that spread and appear as frosted green-gray glass are most likely: A. Pseudomonas spp. B. Bacillus spp. C. Corynebacterium spp. D. Listeria spp.

Bacillus anthracis and Bacillus cereus can best be differentiated by which tests? A. Motility and β-hemolysis on a blood agar plate B. Oxidase and β-hemolysis on a blood agar plate C. Lecithinase and glucose D. Lecithinase and catalase

Which is the specimen of choice for proof of food poisoning by Bacillus cereus? A. Sputum B. Blood C. Stool D. Food

A suspected Bacillus anthracis culture obtained from a wound specimen produced colonies that had many outgrowths (Medusa-head appearance), but were not β-hemolytic on sheep blood agar. Which test should be performed next? A. Penicillin (10-unit) susceptibility test B. Lecithinase test C. Glucose test D. Motility test

Which of the following tests should be performed for initial differentiation of Listeria monocytogenes from group B streptococci? A. Gram stain, motility at room temperature, catalase B. Gram stain, CAMP test, H2S/TSI C. Oxidase, CAMP test, glucose D. Oxidase, bacitracin

Culture of a finger wound specimen from a meat packer produced short gram-positive bacilli on a blood agar plate with no hemolysis. Given the following test results at 48 hours, what is the most likely identification? Catalase = Neg H2S/TSI = + Motility (wet prep) = Neg Motility (media) = Neg (bottle-brush growth in stab culture) A. Bacillus cereus B. Listeria monocytogenes C. Erysipelothrix rhusiopathiae D. Bacillus subtilis

A non–spore-forming, slender gram-positive rod forming palisades and chains was recovered from a vaginal culture and grew well on tomato juice agar. The most likely identification is: A. Lactobacillus spp. B. Bacillus spp. C. Neisseria spp. D. Streptococcus spp.

A Corynebacterium species recovered from a throat culture is considered a pathogen when it produces: A. A pseudomembrane of the oropharynx B. An exotoxin C. Gray-black colonies with a brown halo on Tinsdale’s agar D. All of these options

A presumptive diagnosis of Gardnerella vaginalis can be made using which of the following findings? A. Oxidase and catalase tests B. Pleomorphic bacilli heavily colonized on vaginal epithelium C. Hippurate hydrolysis test D. All of these options

A gram-positive branching filamentous organism recovered from a sputum specimen was found to be positive with a modified acid-fast stain method. What is the most likely presumptive identification? A. Bacillus spp. B. Nocardia spp. C. Corynebacterium spp. D. Listeria spp.

Routine laboratory testing for Treponema pallidum involves: A. Culturing B. Serological analysis C. Acid-fast staining D. Gram staining

Spirochetes often detected in the hematology laboratory, even before the physician suspects the infection, are: A. Borrelia spp. B. Treponema spp. C. Campylobacter spp. D. Leptospira spp.

Which of the following organisms is the cause of Lyme disease? A. Treponema pallidum B. Neisseria meningitidis C. Babesia microti D. Borrelia burgdorferi

The diagnostic method most commonly used for the identification of Lyme disease is: A. Serology B. Culture C. Gram stain D. Acid-fast stain

Primary atypical pneumonia is caused by: A. Streptococcus pneumoniae B. Mycoplasma pneumoniae C. Klebsiella pneumoniae D. Mycobacterium tuberculosis

Which organism typically produces “fried-egg” colonies on agar within 1–5 days of culture from a genital specimen? A. Mycoplasma hominis B. Borrelia burgdorferi C. Leptospira interrogans D. Treponema pallidum

The manganous chloride–urea test is used for the identification of which organism? A. Mycoplasma pneumoniae B. Ureaplasma urealyticum C. Bacillus cereus D. Borrelia burgdorferi

A gram-positive (gram-variable), beaded organism with delicate branching was recovered from the sputum of a 20-year-old patient with leukemia. The specimen produced orange, glabrous, waxy colonies on Middlebrook’s agar that showed partial acid-fast staining with the modified Kinyoun stain. What is the most likely identification? A. Rhodococcus spp. B. Actinomadura spp. C. Streptomyces spp. D. Nocardia spp.

A direct smear from a nasopharyngeal swab stained with Loeffler methylene blue stain showed various letter shapes and deep blue, metachromatic granules. The most likely identification is: A. Corynebacterium spp. B. Nocardia spp. C. Listeria spp. D. Gardnerella spp.

Which of the following is the best, rapid, noncultural test to perform when Gardnerella vaginalis is suspected in a patient with vaginosis? A. 10% KOH test B. 3% H2O2 test C. 30% H2O2 test D. All of these options

Which is the test of choice for the confirmation of Chlamydia trachomatis infection in urine? A. Enzyme immunoassay antigen testing B. PCR molecular testing C. Culture using McCoy and Hela cells D. Microimmunofluorescence (MIF) test

Which test is the most reliable for the detection of Mycoplasma pneumonia in serum and for the confirmation of diagnosis? A. EIA testing and direct antigen testing B. Cold agglutinin testing using Group O RBCs C. Culture on SP4 glucose broth with arginine D. Complement fixation

Identify the following bacterium and specimen pairing that is mismatched (specimen not appropriate for isolation). A. Chlamydia (Chlamydophila) psittaci: fecal swab B. Chlamydia trachomatis: first voided urine C. Chlamydia trachomatis: endocervical swab D. Chlamydia pneumonia: throat swab or sputum

Which of the following organisms are transmitted to animals and humans after a tick bite? A. Leptospira. B. Chlamydia and Mycoplasma spp. C. Neisseria sicca D. Ehrlichia and Anaplasma spp

Following a hike in the woods, a young male noted a tick on his ankle. He removed the tick, but 2 weeks later noticed a circular, bull’s eye rash at the site of the bite. Which specimen(s) should be obtained to establish a diagnosis of Lyme borreliosis? A. Lymph node biopsy, skin scraping B. Blood, CSF, and skin biopsy C. Hair, fingernails D. Saliva, sputum

Obligate anaerobes, facultative anaerobes, and microaerophiles are terms referring to bacteria that require: A. Increased nitrogen B. Decreased CO2 C. Increased O2 D. Decreased O2

Which of the following most affects the oxidation–reduction potential (Eh or redox potential) of media for anaerobic bacteria? A. O2 B. Nitrogen C. pH D. Glucose

Which of the following is the medium of choice for the selective recovery of gram-negative anaerobes? A. Kanamycin–vancomycin (KV) agar B. Phenylethyl alcohol (PEA) agar C. Cycloserine–cefoxitin–fructose agar (CCFA) D. THIO broth

Anaerobic bacteria are routinely isolated from all of the following types of infections except: A. Lung abscesses B. Brain abscesses C. Dental infections D. Urinary tract infections

Methods other than packaged microsystems used to identify anaerobes include: A. Antimicrobial susceptibility testing B. Gas–liquid chromatography (GLC) C. Special staining D. Enzyme immunoassay

Which broth is used for the cultivation of anaerobic bacteria in order to detect volatile fatty acids as an aid to identification? A. Prereduced peptone–yeast extract–glucose (PYG) B. THIO broth C. Gram-negative (GN) broth D. Selenite (SEL) broth

A gram-positive spore-forming bacillus growing on sheep-blood agar anaerobically produces a double zone of β-hemolysis and is positive for lecithinase. What is the presumptive identification? A. Bacteroides ureolyticus B. Bacteroides fragilis C. Clostridium perfringens D. Clostridium difficile

Egg yolk agar is used to detect which enzyme produced by Clostridium species? A. Lecithinase B. β-Lactamase C. Catalase D. Oxidase

Which of the following organisms will display lipase activity on egg yolk agar? A. Clostridium botulinum B. Clostridium sporogenes C. Clostridium novyi (A) D. All of these

Which spore type and location is found on Clostridium tetani? A. Round, terminal spores B. Round, subterminal spores C. Ovoid, subterminal spores D. Ovoid, terminal spores

Which mechanism is responsible for botulism in infants caused by Clostridium botulinum? A. Ingestion of spores in food or liquid B. Ingestion of preformed toxin in food C. Virulence of the organism D. Lipase activity of the organism

The classic form of foodborne botulism is characterized by the ingestion of: A. Spores in food B. Preformed toxin in food C. Toxin H D. All of these options

Gram-positive bacilli recovered from two blood cultures from a 60-year-old diabetic patient gave the following results: Spores seen: Neg Motility= Neg Hemolysis= + (double zone) Lecithinase= + Volatile acids by GLC (PYG) = Acetic acid and butyric acid What is the most likely identification? a. C. tetani b. C. perfringens c. C. novyi d. C. sporogenes

The classic form of foodborne botulism is characterized by the ingestion of: A. Spores in food B. Preformed toxin in food C. Toxin H D. All of these options

Which test is performed in order to confirm an infection with Clostridium botulinum? A. Toxin neutralization B. Spore-forming test C. Lipase test D. Gelatin hydrolysis test

Which Clostridium spp. causes pseudomembranous colitis or antibiotic-associated colitis? A. C. ramosum B. C. difficile C. C. perfringens D. C. sporogenes

Identification of Clostridium tetani is based upon: A. Gram stain of the wound site B. Anaerobic culture of the wound site C. Blood culture results D. Clinical findings

Obligate anaerobic gram-negative bacilli that do not form spores grow well in 20% bile and are resistant to penicillin 2-unit disks are most likely: A. Porphyromonas spp. B. Bacteroides spp. C. Fusobacterium spp. D. Prevotella spp.

Which Bacteroides spp. is noted for “pitting” of the agar and is sensitive to penicillin 2-unit disks? A. B. vulgatus B. B. ovatus C. B. thetaiotaomicron D. B. ureolyticus

Which gram-negative bacilli produce black pigment and brick red fluorescence when exposed to an ultraviolet light source? A. Porphyromonas spp. and Prevotella spp. B. Fusobacterium spp. and Actinomyces spp. C. Bacteroides spp. and Fusobacterium spp. D. All of these options

The following characteristics of an obligate anaerobic gram-negative bacilli best describe which of the listed genera? Gram stain: long, slender rods with pointed ends Colonial appearance: dry bread crumbs or “fried-egg” appearance Penicillin 2-unit disk test: Susceptible A. Bacteroides spp. B. Fusobacterium spp. C. Prevotella spp. D. Porphyromonas spp.

All of the following genera are anaerobic cocci that stain gram positive except: A. Peptococcus spp. B. Peptostreptococcus spp. C. Streptococcus spp. D. Veillonella spp.

The gram-positive non–spore-forming anaerobic rods most frequently recovered from blood cultures as a contaminant are: A. Propionibacterium acnes B. Clostridium perfringens C. Staphylococcus intermedius D. Veillonella parvula

Which Clostridium species is most often recovered from a wound infection with gas gangrene? A. C. sporogenes B. Clostridium sordellii C. C. novyi D. C. perfringens

Gram stain of a smear taken from the periodontal pockets of a 30-year-old man with poor dental hygiene showed sulfur granules containing gram-positive rods (short diphtheroids and some unbranched filaments). Colonies on blood agar resembled “molar teeth” in formation. The most likely organism is: A. Actinomyces israelii B. Propionibacterium acnes C. Staphylococcus intermedius D. Peptostreptococcus anaerobius

Antimicrobial susceptibility testing of anaerobes is done by which of the following methods? A. Broth disk elution B. Disk agar diffusion C. Microtube broth dilution D. β-Lactamase testing

The best specimen for recovery of the mycobacteria from a sputum sample is: A. First morning specimen B. 10-hour evening specimen C. 12-hour pooled specimen D. 24-hour pooled specimen

What concentration of sodium hydroxide (NaOH) is used to prepare a working decontamination solution for the processing of not normally sterile specimens for mycobacteria? A. 1% NaOH B. 4% NaOH C. 8% NaOH D. 12% NaOH

Which is the most appropriate nonselective medium for recovery of mycobacteria from a heavily contaminated specimen? A. Löwenstein–Jensen agar B. Middlebrook 7H10 agar C. Petragnani’s agar D. American Thoracic Society medium

Mycobacteria stained by the Ziehl–Neelsen or Kinyoun methods with methylene blue counterstain are seen microscopically as: A. Bright red rods against a blue background B. Bright yellow rods against a yellow background C. Orange-red rods against a black background D. Bright blue rods against a pink background

Acid-fast staining of a smear prepared from digested sputum showed slender, slightly curved, beaded, red mycobacterial rods. Growth on Middlebrook 7H10 slants produced buff-colored microcolonies with a serpentine pattern after 14 days at 37°C. Niacin and nitrate reduction tests were positive. What is the most probable presumptive identification? A. Mycobacterium tuberculosis B. Mycobacterium ulcerans C. Mycobacterium kansasii D. Mycobacterium avium–intracellulare complex

Which organism, associated with tuberculosis in cattle, causes tuberculosis in humans, especially in regions where dairy farming is prevalent? A. Mycobacterium avium–intracellulare complex B. Mycobacterium kansasii C. Mycobacterium marinum D. Mycobacterium bovis

Which of the following organisms are used as controls for rapid growers and slow growers? A. Mycobacterium fortuitum and Mycobacterium tuberculosis B. Mycobacterium avium-intracellulare complex and Mycobacterium tuberculosis C. Mycobacterium chelonei and Mycobacterium fortuitum D. Mycobacterium kansasii and Mycobacterium tuberculosis

Which of the following Mycobacterium spp. produce(s) pigmented colonies in the dark (is a scotochromogen)? A. M. szulgai B. M. kansasii C. M. tuberculosis D. All of these options

All of the following mycobacteria are associated with skin infections except: A. Mycobacterium marinum B. Mycobacterium haemophilum C. Mycobacterium ulcerans D. Mycobacterium kansasii

All of the following Mycobacterium spp. produce the enzyme required to convert niacin to niacin ribonucleotide except: A. M. kansasii B. M. tuberculosis C. M. avium–intracellulare complex D. M. szulgai

The catalase test for mycobacteria differs from that used for other types of bacteria by using: A. 1% H2O2 and 10% Tween 80 B. 3% H2O2 and phosphate buffer, pH 6.8 C. 10% H2O2 and 0.85% saline D. 30% H2O2 and 10% Tween 80

Growth inhibition by thiophene-2-carboxylic hydrazide (T2H) is used to differentiate M. tuberculosis from which other Mycobacterium specie? A. M. bovis B. M. avium–intracellulare complex C. M. kansasii D. M. marinum

Which of the following Mycobacterium spp. is best differentiated by the rapid hydrolysis of Tween 80? A. M. fortuitum B. M. chelonae C. M. kansasii D. M. gordonae

Mycobacteria isolated from the hot water system of a hospital grew at 42°C. Colonies on Löwenstein–Jensen medium were not pigmented after exposure to light and were negative for niacin accumulation and nitrate reduction. The most likely identification is: A. Mycobacterium xenopi B. Mycobacterium marinum C. Mycobacterium ulcerans D. Mycobacterium haemophilum

The urease test is needed to differentiate Mycobacterium scrofulaceum from which of the following mycobacteria? A. M. gordonae B. M. kansasii C. M. avium–intracellulare complex D. M. bovis

A laboratory provides the following services for identification of mycobacteria: Acid-fast staining of clinical specimens Inoculation of cultures Shipment of positive cultures to a reference laboratory for identification According to the American Thoracic Society’s definition for levels of service this laboratory is: A. Level I B. Level II C. Level III D. Level IV

According to the College of American Pathologists (CAP) guidelines, which services for mycobacteria would be performed by a Level II laboratory? A. No procedures performed B. Acid-fast staining, inoculation, and referral to a reference laboratory C. Isolation and identification of Mycobacterium tuberculosis; preliminary identification of other species D. Definitive identification of all mycobacteria

A Mycobacterium species recovered from a patient with AIDS gave the following results: Niacin = Neg Tween 80 hydrolysis = Neg Heat-stable catalase (68°C) = ± Nonphotochromogen T2H = + Nitrate reduction = Neg What is the most likely identification? A. M. gordonae B. M. bovis C. M. avium–intracellulare complex D. M. kansasii

Culture of a skin (hand) wound from a manager of a tropical fish store grew on Löwenstein–Jensen agar slants at 30°C in 10 days but did not grow on the same media at 37°C in 20 days. Given the following results, what is the most likely identification? Photochromogen = + Niacin = Neg Heat-stable catalase (68°C) = Neg Nitrate reduction = Neg Tween80 hydrolysis = Pos Urease= Pos A. Mycobacterium marinum B. Mycobacterium kansasii C. Mycobacterium avium-intracellulare complex D. Mycobacterium tuberculosis

Which nonpathogenic Mycobacterium specie is isolated most often from clinical specimens and is called the “tapwater bacillus”? A. M. kansasii B. M. avium–intracellulare complex C. M. leprae D. M. gordonae

Which of the following drugs are first-line antibiotics used to treat classic tuberculosis for which susceptibility testing is performed by the disk diffusion method on Middlebrook 7H10 or 7H11 agar plates? A. Ampicillin, penicillin, streptomycin, and carbenicillin B. Ampicillin, penicillin, and methicillin C. Vancomycin, methicillin, and carbenicillin D. Isonicotinic acid hydrazide (INH), rifampin, ethambutol, and pyrazinamide

How long should Mycobacterium tuberculosis–positive cultures be kept by the laboratory after identification and antibiotic susceptibility testing have been performed? A. 1–2 months B. 2–4 months C. 5–6 months D. 6–12 months

According to the reporting standards of the American Thoracic Society, one or more acid-fast bacilli (AFB) per oil immersion field (1,000×) are reported as: A. Numerous or 3+ B. Few or 2+ C. Rare or 1+ D. Indeterminate; a new specimen should be requested

Which of the following Mycobacterium spp. would be most likely to grow on a MacConkey agar plate? A. M. chelonae–fortuitum complex B. M. ulcerans C. M. marinum D. M. avium–intracellulare complex

Rapid methods for identifying classic infection with M. tuberculosis include: A. Gas–liquid chromatography B. Nucleic acid probes C. Acid-fast smears D. All of these options

Individuals showing a positive purified protein derivative (PPD) skin test for M. tuberculosis are usually: A. Infective B. Symptomatic of pulmonary disease C. Latently infected D. Falsely positive

Which of the following Mycobacterium species is diagnosed by means other than culture? A. M. leprae B. M. bovis C. M. canetti D. M. avium

Which M. avium complex (MAC) organism is the most frequently isolated mycobacterium from AIDS patients? A. M. avium B. M. intracellulare C. M. scrofulaceum D. M. bovis

Which mycobacterium of the M. tuberculosis complex fails to grow in culture and has a characteristic “croissant-like” morphology in stained smears? A. M. africanum B. M. microti C. M. bovis D. M. leprae

Which two mycobacteria commonly isolated from subcutaneous skin have an optimal growth temperature of 30°C? A. M. haemophilum and M. ulcerans B. M. kansasii and M. xenopi C. M. gordonae and M. avium D. M. simiae and M. avium

Which mycobacterium is associated with Crohn’s disease? A. M. marinum B. M. paratuberculosis C. M. avium D. M. gordonae

Which temperature range is ideal for the recovery of M. marinum? A. 24°C–26°C B. 30°C–32°C C. 42°C–44°C D. 44°C–48°C

All of the following are examples of appropriate specimens for the recovery of fungi except: A. Tissue biopsy B. CSF C. Aspirate of exudate D. Swab

For which clinical specimens is the KOH direct mount technique for examination of fungal elements used? A. Skin B. CSF C. Blood D. Bone marrow

The India ink stain is used as a presumptive test for the presence of which organism? A. Aspergillus niger in blood B. Cryptococcus neoformans in CSF C. Histoplasma capsulatum in CSF D. Candida albicans in blood or body fluids

Cutaneous disease involving skin, hair, and nails usually indicates an infection with a: A. Dimorphic fungus B. Dermatophyte C. Zygomycetes D. Candida species

What is the first step to be performed in the identification of an unknown yeast isolate? A. Gram stain smear B. India ink stain C. Catalase test D. Germ tube test

An isolate produced a constriction that was interpreted as a positive germ tube, but Candida albicans was ruled out when confirmatory tests were performed. Which of the following fungi is the most likely identification? A. Candida tropicalis B. Cryptococcus neoformans C. Candida glabrata D. Rhodotorula rubra

Cornmeal agar with Tween 80 is used to identify which characteristic of an unknown yeast isolate? A. Hyphae (true and pseudo) B. Blastoconidia and arthroconidia C. Chlamydospores D. All of these options

Blastoconidia are the beginning of which structures? A. Arthroconidia B. Germ tubes C. Pseudohyphae D. True hyphae

An isolate from CSF growing on cornmeal agar produces the following structures: Blastoconidia = + Pseudohyphae = Neg Chlamydospores = Neg Arthroconidia= Neg Which tests should be performed next? A. Birdseed agar and urease B. Germ tube and glucose C. India ink and germ tube D. All of these options

Which of the following yeast enzymes is detected using birdseed (niger seed) agar? A. Phenol oxidase B. Catalase C. Urease D. Nitrate reductase

Which of the following yeasts is characteristically positive for germ tube production? A. Candida tropicalis B. Candida kefyr (pseudotropicalis) C. Cryptococcus neoformans D. Candida albicans

Arthroconidia production is used to differentiate which two yeast isolates? A. Candida albicans and Candida dubliniensis B. Trichosporon cutaneum and Cryptococcus neoformans C. Candida albicans and Candida tropicalis D. Saccharomyces cerevisiae and Candida glabrata

The urease test, niger seed agar test, and the germ tube test are all used for the presumptive identification of: A. Rhodotorula rubra B. Cryptococcus neoformans C. Trichosporon cutaneum D. Candida albicans

Which of the following yeasts produces only blastoconidia on cornmeal Tween 80 agar? A. Candida spp. B. Trichosporon spp. C. Geotrichum spp. D. Cryptococcus

Ascospores are formed by which yeast isolate? A. Saccharomyces cerevisiae B. Candida albicans C. Cryptococcus neoformans D. All of these options

A germ tube–negative, pink yeast isolate was recovered from the respiratory secretions and urine of a patient with AIDS. Given the following results, what is the most likely identification? CORNMEAL TWEEN 80 AGAR Blastoconidia = + Arthroconidia= Neg Pseudohyphae = Neg Urease = + A. Candida albicans B. Rhodotorula spp. C. Cryptococcus spp. D. Trichosporon

Chlamydospore production is demonstrated by which Candida species? A. C. glabrata B. C. krusei C. C. albicans D. C. tropicalis

Carbohydrate assimilation tests are used for the identification of yeast isolates by inoculating media: A. Free of carbohydrates B. Free of niger seed C. Containing carbohydrates D. Containing yeast extract

Yeast recovered from the urine of a catheterized patient receiving chemotherapy for cancer gave the following results: CORNMEAL TWEEN 80 AGAR Germ tube = + Blastoconidia = + Pseudohyphae = + Arthroconidia= Neg Chlamydospores = + What further testing is necessary? A. Carbohydrate assimilation and urease B. Urease and niger seed C. Nitrate reductase and carbohydrate fermentation D. No further testing is needed for identification

A blood agar plate inoculated with sputum from a patient diabetes mellitus grew very few bacterial flora and a predominance of yeast. Given the following results, what is the most likely identification of the yeast isolate? Cornmeal Tween Agar Germ tube = Neg Arthroconidia = Neg Chlamydospores = Neg Pseudohyphae = + Blastoconidia = + (arranged along pseudohyphae) A. Candida tropicalis B. Candida kefyr (pseudotropicalis) C. Trichosporon cutaneum D. Geotrichum candidum

Dimorphic molds are found in infected tissue in which form? A. Mold phase B. Yeast phase C. Encapsulated D. Latent

The mycelial form of which dimorphic mold produces thick-walled, rectangular, or barrel-shaped alternate arthroconidia? A. Coccidioides immitis B. Sporothrix schenckii C. Histoplasma capsulatum D. Blastomyces dermatitidis

The yeast form of which dimorphic fungus appears as oval or elongated cigar shapes? A. Coccidioides immitis B. Sporothrix schenckii C. Histoplasma capsulatum D. Blastomyces dermatitidis

The mycelial form of Histoplasma capsulatum seen on agar resembles: A. Sepedonium spp. B. Penicillium spp. C. Sporothrix spp. D. Coccidioides spp.

Which group of molds can be ruled out when septate hyphae are observed in a culture? A. Dematiaceous B. Zygomycetes C. Dermatophytes D. Dimorphic molds

Tinea versicolor is a skin infection caused by: A. Malassezia furfur B. Trichophyton rubrum C. Trichophyton schoenleinii D. Microsporum gypseum

Which of the following structures is invaded by the genus Trichophyton? A. Hair B. Nails C. Skin D. All of these options

An organism cultured from the skin produces colonies displaying a cherry-red color on Sabouraud dextrose agar after 3–4 weeks and teardrop-shaped microconidia along the sides of the hyphae. The most likely identification is: A. Trichophyton rubrum B. Trichophyton tonsurans C. Trichophyton schoenleinii D. Trichophyton violaceum

Which Microsporum species causes an epidemic form of tinea capitis in children? A. Microsporum canis B. Microsporum audouinii C. Microsporum gypseum D. All of these options

Microscopic examination of a fungus cultured from a patient with athlete’s foot showed large, smooth-walled, club-shaped macroconidia appearing singly or in clusters of two to three from the tips of short conidiophores. The colonies did not produce microconidia. What is the most likely identification? A. Trichophyton spp. B. Alternaria spp. C. Epidermophyton spp. D. Microsporum spp.

Which Trichophyton species causes the favus type of tinea capitis seen in the Scandinavian countries and in the Appalachian region of the United States? A. T. verrucosum B. T. violaceum C. T. tonsurans D. T. schoenleinii

The Hair Baiting Test is used to differentiate which two species of Trichophyton that produce red colonies on Sabouraud agar plates? A. T. mentagrophytes and T. rubrum B. T. tonsurans and T. schoenleinii C. T. tonsurans and T. violaceum D. T. verrucosum and T. rubrum

A mold that produces colonies with a dark brown, green-black, or black appearance of both the surface and reverse side is classified as a: A. Dematiaceous mold B. Dermatophyte C. Hyaline mold D. Dimorphic fungus

A rapidly growing hyaline mold began as a white colony but soon developed a black “pepper” effect on the agar surface. The older colony produced a black matte, making it resemble a dematiaceous mold. What is the most likely identification? A. Penicillium notatum B. Aspergillus niger C. Paecilomyces spp. D. Scopulariopsis spp.

Which Aspergillus species, recovered from sputum or bronchial mucus, is the most common cause of pulmonary aspergillosis? A. A. niger B. A. flavus C. A. fumigatus D. All of these options

A hyaline mold recovered from a patient with AIDS produced rose-colored colonies with lavender centers on Sabouraud dextrose agar. Microscopic examination showed multiseptate macroconidia appearing as sickles or canoes. What is the most likely identification? A. Fusarium spp. B. Wangiella spp. C. Exophiala spp. D. Phialophora spp.

Material from a fungus-ball infection produced colonies with a green surface on Sabouraud agar in 5 days at 30°C. Microscopic examination showed club-shaped vesicles with sporulation only from the top half of the vesicle. This hyaline mold is most probably which Aspergillus spp.? A. A. niger B. A. fumigatus C. A. flavus D. A. terreus

A rapidly growing nonseptate mold produced colonies with a gray surface resembling cotton candy that covered the entire plate. Microscopic examination revealed sporangiophores arising between, not opposite, the rhizoids and producing pear-shaped sporangia. What is the most likely identification? A. Absidia spp. B. Penicillium spp. C. Rhizopus spp. D. Aspergillus spp.

A bone marrow sample obtained from an immunocompromised patient revealed small intracellular cells using a Wright’s stain preparation. Growth on Sabouraud–dextrose agar plates of a mold phase at 25°C and a yeast phase at 37°C designates the organism as dimorphic. The mold phase produced thick, spherical tuberculated macroconidia. What is the most likely identification? A. Histoplasma capsulatum B. Sepedonium spp. C. Sporothrix schenckii D. Coccidioides immitis

A lung biopsy obtained from an immunocompromised patient showed many “cup-shaped” cysts (gray to black) in a foamy exudate (green background) using Gomori methenamine silver (GMS) stain. The organism cannot be cultured because it does not grow on routine culture media for molds. The patient was diagnosed with pneumonia that resisted antibiotic treatment. The most likely identification is? A. Pneumocystis jirovecci (carinii) B. Histoplasma capsulatum C. Sporothrix schenckii D. Scopulariopsis spp.

Upon direct examination of a sputum specimen, several spherules were noted that contained endospores. Growth on Sabouraud–dextrose agar showed aerial mycelial elements. The septate hyphae produced barrel-shaped arthroconidia. What is the most likely identification? A. Penicillium marneffei B. Scopulariopsis spp. C. Cryptococcus neoformans D. Coccidioides immitis

A bone marrow specimen was obtained from an immunocompromised patient who tested positive for HIV. The organism grew rapidly at 3 days showing a mold form (at 25°C), displaying conidiophores with four to five terminal metulae with each having four to six phialides. The conidia at the end of the phialides were oval and in short chains. They appear as a fan or broom when viewing under 10× and 40×. At 37°C, the yeast form grew more slowly, showing conidia that formed hyphal elements breaking at the septa to produce oval arthroconidia. This thermo- dimorphic mold is most likely: A. Paecilomyces spp. B. Penicillium marneffei C. Rhizomucor spp. D. Aspergillus fumigatus

What is the specimen of choice for the initial diagnosis of Pneumocystis jirovecii (carinii) in an immunocompromised patient, such as someone with AIDS? A. Induced sputum B. Open-thorax lung biopsy C. CSF D. Urine

A transplant patient is suspected of having invasive aspergillosis on the basis of clinical and radiological findings. Which specimen is best for the initial identification of aspergillosis by soluble antigen testing? A. Blood culture B. Lung biopsy C. Serum or urine D. Sputum

What is the most common cause of mucormycosis infection in humans? A. Penicillium spp. B. Candida albicans C. Scopulariopsis spp. D. Rhizopus spp.

A thermally dimorphic fungus shows a filamentous mold form with tuberculate macroconidia at room temperature, and a yeast form above 35°C. Which organism best fits this description? A. Histoplasma capsulatum B. Paracoccidioides brasiliensis C. Candida albicans D. Coccidioides immitis

SITUATION: After a vacation to the Southwestern United States, a midwesterner complained of flulike symptoms with fever, chills, nonproductive cough, and chest pain. Microscopic exam of sputum, cleared with KOH, revealed large, thick-walled spherules containing endospores. Upon culture, the mold phase showed septate hyphae and alternating barrel-shaped arthroconidia. Which organism is most likely the cause of this pneumonia? A. Coccidioides immitis B. Histoplasma capsulatum C. Paracoccidioides brasiliensis D. Penicillium marneffei

Classification of viruses is made by: A. Complement fixation serology B. Electron microscopy C. Nucleic acid composition D. Cellular inclusion bodies

Which virus is the most common etiological agent of viral respiratory diseases in infants and children? A. Respiratory syncytial virus (RSV) B. Measles virus C. Coxsackie A virus D. Coxsackie B virus

The most common viral syndrome of pericarditis, myocarditis, and pleurodynia (pain upon breathing) is caused by: A. Herpes simplex virus B. Respiratory syncytial virus C. Epstein–Barr virus D. Coxsackie B virus

Which of the following viruses is implicated along with Epstein–Barr virus as a cause of infectious mononucleosis? A. Cytomegalovirus (CMV) B. Coxsackie A virus C. Coxsackie B virus D. Hepatitis B virus

The most common causes of viral pneumonia in adults are: A. Influenza and adenovirus B. Hepatitis A and B viruses C. Coxsackie A and B viruses D. Herpes simplex and CMV

Which virus belonging to the Reoviridae group causes gastroenteritis in infants and young children but an asymptomatic infection in adults? A. Coxsackie B virus B. Rotavirus C. Respiratory syncytial virus D. Rhabdovirus

A very small, single-stranded DNA virus that causes a febrile illness with a rash and is called the fifth childhood disease after rubeola, rubella, varicella, and roseola is: A. Rotavirus B. Adenovirus type 40 C. Coxsackie A virus D. Parvovirus B19

Hepatitis B virus can be transmitted by: A. Acupuncture B. Tattoos C. Sexual contact D. All of these options

Which virus has been implicated in adult gastroenteritis resulting from ingestion of contaminated food (especially shellfish) and water? A. Norwalk-like viruses B. Rotavirus C. Hepatitis C virus D. Coronavirus

Which virus is associated with venereal and respiratory tract warts and produces lesions of skin and mucous membranes? A. Polyomavirus B. Poxvirus C. Adenovirus D. Papillomavirus

A clinical test used for the detection and identification of viral infections other than culture is: A. Hemagglutination B. Hemadsorption C. Viral antigen detection D. All of these options

Which technique is used for the confirmation of infection with human immunodeficiency virus (HIV-1)? A. Western blot (immunoblot) assay B. Enzyme-linked immunosorbent assay (ELISA) C. Complement fixation D. p24 Antigen testing

A 13-year-old boy was admitted to the hospital with a diagnosis of viral encephalitis. History revealed that the boy harbored wild raccoons from nearby woods. What is the best method to determine if the boy has contracted rabies? A. Remove the brainstems from all of the raccoons and examine for cytopathic effects B. Request immunofluorescent test for antibody on the saliva from all of the raccoons C. Request immunofluorescent test for antigen in cutaneous nerves obtained by nuchal biopsy of the patient D. Isolate the virus from the saliva of both the animals and the patient

A 65-year-old woman was admitted to the hospital with acute respiratory distress, fever, myalgia, and headache. Influenza A or B was suspected after ruling out bacterial pneumonia. Which of the following methods could be used to confirm influenza infection? A. Influenza virus culture in Madin–Darby canine kidney B. Hemagglutination-inhibition test for antibodies in the patient’s serum C. Direct examination of nasal epithelium for virus using fluorescent antibody stain D. All of these options

The most rapid definitive diagnosis of a genital herpes simplex (HSV-2) infection in a 20-year-old man is made by which method? A. Direct immunofluorescence test for viral antigen in vesicle fluid B. Titer of serum and seminal fluid for antibodies to herpes simplex C. Detection of antiherpes simplex in seminal fluid D. Cell culture of vesicle fluid

A 20-year-old female college student complained of a sore throat and extreme fatigue. The physician noted lymphadenopathy and ordered a rapid test for infectious mononucleosis antibodies that was negative. Bacterial cultures were negative, as were serological tests for influenza A and B, HIV-1, CMV, hepatitis B, and antistreptolysin O. What would be the next line of viral testing to establish a diagnosis? A. Herpes simplex B. Rubella C. Epstein–Barr D. West Nile

A 60-year-old male gardener from New York State was hospitalized with flulike symptoms and eventually diagnosed with encephalitis. While working in his garden, he noticed several dead birds around his bird feeder. The region was known to be heavily infested with mosquitoes. What is the most likely cause of his illness? A. West Nile virus B. Epstein–Barr virus C. Parvovirus D. Hantavirus

A 30-year-old male patient who was a contractor and building inspector in the southwestern United States complained of difficulty breathing and was admitted to the hospital with severe respiratory disease. The physician noted a high fever and cough. Two days before, the patient had inspected an old warehouse, abandoned and infested with rodents. The patient was given intravenous antibiotics, but 2 days into therapy the pneumonia worsened and he developed pulmonary edema. Which organism should be suspected of causing his illness? A. Hantavirus B. Rotavirus C. West Nile virus D. Norwalk-like virus

A 3-year-old female was admitted to the hospital following a 2-day visit with relatives over the Christmas holidays. Vomiting and diarrhea left the child severely dehydrated. No other members of the family were affected. All bacterial cultures proved negative. A stool sample should be tested for which virus? A. CMV B. EBV C. Hepatitis D D. Rotavirus

A 25-year-old male patient was diagnosed with HIV-1 by enzyme immunoassay, testing positive twice, and the diagnosis was confirmed by Western blot testing. Which laboratory test should be performed prior to initiating antiviral therapy? A. Quantitative plasma virus concentration (viral load testing) B. Quantitation of CD4 lymphocytes C. Phenotype/genotype resistance testing D. All of these options

A 6-month-old male infant was hospitalized with a respiratory infection. He was diagnosed with apnea and bronchiolitis. Further testing revealed congenital heart disease. Bacterial cultures were negative for Streptococcus pneumoniae and Haemophilus influenzae. What further testing should be done? A. Respiratory syncytial virus (RSV) B. Rotavirus C. Norwalk virus D. HIV

A young male hunter encountered a fox in his path during a walk in the woods. The fox was staggering but appeared nonthreatening. The man tried to avoid contact but was attacked and bitten on the leg. The bite broke the skin but was not deep. Wildlife officials were unable to locate the fox for testing. What procedure should take place next for the hunter? A. Spinal tap with CSF testing for rabies virus B. Administration of hyperimmune antirabies globulin and rabies vaccine C. Biopsy of the wound site D. Throat culture and blood culture

A 40-year-old female experienced a respiratory infection after returning home from a visit to her homeland of China. A rapid onset of pneumonia in the lower respiratory area prompted the physician to place her in isolation. She was diagnosed presumptively with severe acute respiratory syndrome (SARS) and placed on a respirator. What type of testing should be done next to diagnose this disease? A. Molecular technique and cell culture B. Latex agglutination test C. Blood culture D. Complement fixation

A pregnant 25-year-old female with genital lesions delivered a premature newborn with complications. The baby tested negative for bacterial infection (cultures of blood and urine). Antigen testing of the baby’s urine proved negative for group B streptococci and Streptococcus pneumoniae. The mother tested negative for bacterial sexually transmitted diseases and for group B streptococci. The baby was treated with acyclovir and failed to survive. What was the most likely cause of death? A. CMV B. Human immunodeficiency virus C. Respiratory syncytial virus D. Herpes simplex virus

A young father of two small children complained of a rash on the torso of his body. The children had been diagnosed with chickenpox and confined to their home. The father had experienced chickenpox as a child and knew he did not have the same rash as his children. What is the most likely cause of the father’s rash? A. Herpes simplex 1 virus B. Varicella-zoster virus C. Herpes simplex 2 virus D. Epstein–Barr virus

The organs of a 65-year-old male were donated soon after a fatal auto accident. Three recipients of his corneas and kidneys died within weeks after receiving his organs. Which of the following viruses most likely caused the death of these recipients? A. HIV B. Rabies C. Norwalk-like D. Rotavirus

While on a 7-day cruise to Vancouver and Alaska, a number of passengers reported to the ship’s medical staff complaining of vomiting and diarrhea. Which is the most likely virus to have infected these mainly adult passengers? A. Rotavirus B. Parainfluenza C. Respiratory syncytial D. Norwalk or Norwalk-like viruses

SITUATION: A patient tested positive for HIV-1 infection using a reverse transcriptase-polymerase chain reaction (RT-PCR) method. However, 1 week later a second blood sample was collected and sent to a reference lab that performed a confirmatory test by Western blot. The Western blot test was negative. What best explains these results? A. The samples for RT-PCR and Western blot were not from the same patient B. RT-PCR is more sensitive for early detection C. The RT-PCR result was falsely positive D. The RT-PCR test detected HIV-2 and the Western blot is specific for HIV-1

SITUATION: A pregnant women was seen by her obstetrician with signs of flulike illness during her second trimester. NAT tests were ordered for Toxoplasma gondii, rubella, cytomegalovirus, and herpes simplex 1 and 2. All test results were negative. However, after delivery, the newborn exhibited signs of an infection and failed to survive. Which virus causes a 90% transplacental infection rate when found in the mother? A. Hepatitis A B. Hepatitis B C. Hepatitis D D. Hepatitis G

An immunocompromised patient was admitted to the hospital with a diagnosis of hemorrhagic cystitis. Which combination of virus and specimen would be most appropriate to diagnose a viral cause of this disorder? A. BK virus—urine B. Human papilloma virus—skin C. Hepatitis B virus—serum D. Epstein–Barr virus—serum

The incorrect match between organism and the appropriate diagnostic procedure is: A. Onchocerca volvulus—examination of skin snips B. Cryptosporidium—modified acid-fast stain C. Echinococcus granulosus—routine ova and parasite examination D. Schistosoma haematobium—examination of urine sediment

In a patient with diarrhea, occasionally Entamoeba histolytica/E. dispar (four nucleated cysts, no chromatoidal bars) are identified as being present; however, these cells, which are misdiagnosed as protozoa, are really: A. Macrophages B. Polymorphonuclear leukocytes C. Epithelial cells D. Eosinophils

Charcot–Leyden crystals in stool may be associated with an immune response and are thought to be formed from the breakdown products of: A. Neutrophils B. Eosinophils C. Monocytes D. Lymphocytes

Parasitic organisms that are most often transmitted sexually include: A. Entamoeba gingivalis B. Dientamoeba fragilis C. Trichomonas vaginalis D. Diphyllobothrium latum

The incorrect match between the organism and one method of acquiring the infection is: A. Trypanosoma brucei rhodesiense—bite of sand fleas B. Giardia lamblia—ingestion of water contaminated with cysts C. Hookworm—skin penetration of larvae from soil D. Toxoplasma gondii—ingestion of raw or rare meats

Upon examination of stool material for Cystoisospora belli, one would expect to see: A. Cysts containing sporozoites B. Precysts containing chromatoidal bars C. Oocysts that are modified acid-fast variable D. Sporozoites that are hematoxylin positive

Which specimen is the least likely to provide recovery of Trichomonas vaginalis? A. Urine B. Urethral discharge C. Vaginal discharge D. Feces

Which of the following is the best technique to identify Dientamoeba fragilis in stool? A. Formalin concentrate B. Trichrome-stained smear C. Modified acid-fast–stained smear D. Giemsa’s stain

One of the following protozoan organisms has been implicated in waterborne and foodborne outbreaks within the United States. The suspect organism is: A. Pentatrichomonas hominis B. Dientamoeba fragilis C. Giardia lamblia D. Balantidium coli

A Gram stain from a gum lesion showed what appeared to be amoebae. A trichrome smear showed amoebae with a single nucleus and partially digested PMNs. The correct identification is: A. Trichomonas tenax B. Entamoeba histolytica/E. dispar C. Entamoeba gingivalis D. Entamoeba polecki

An Entamoeba histolytica trophozoite has the following characteristics: A. Central karyosome in the nucleus, ingested RBCs, and clear pseudopodia B. Ingested RBCs, clear pseudopodia, and uneven chromatin on the nuclear membrane C. Ingested RBCs, clear pseudopodia, and large glycogen vacuoles in cytoplasm D. Large, blotlike karyosome, ingested white blood cells (WBCs), and granular pseudopods

A 12-year-old girl is brought to the emergency department with meningitis and a history of swimming in a warm-water spring. Motile amoebae that measure 10 μ in size are seen in the CSF and are most likely: A. Iodamoeba bütschlii trophozoites B. Endolimax nana trophozoites C. Dientamoeba fragilis trophozoites D. Naegleria fowleri trophozoites

Characteristics of the rhabditiform (noninfective) larvae of Strongyloides stercoralis include a: A. Short buccal capsule and large genital primordium B. Long buccal capsule and pointed tail C. Short buccal capsule and small genital primordium D. Small genital primordium and notch in tail

Visceral larva migrans is associated with which of the following organisms? A. Toxocara—serology B. Onchocerca—skin snips C. Dracunculus—skin biopsy D. Angiostrongylus—CSF examination

The following organisms are linked with specific, relevant information. The incorrect combination is: A. Strongyloides stercoralis—internal autoinfection B. Echinococcus granulosus—hydatid examination C. Toxoplasma—serology D. Balantidium coli—common within the United States

Examination of 24-hour unpreserved urine specimen is sometimes helpful in the recovery of: A. Trichomonas vaginalis trophozoites B. Schistosoma haematobium eggs C. Enterobius vermicularis eggs D. Strongyloides stercoralis larvae

The examination of sputum may be necessary to diagnose infection with: A. Paragonimus westermani B. Trichinella spiralis C. Wuchereria bancrofti D. Fasciola hepatica

Two helminth eggs that may resemble one another are: A. Diphyllobothrium latum and Paragonimus westermani B. Opisthorchis sinensis and Fasciolopsis buski C. Taenia saginata and Hymenolepis nana D. Ascaris lumbricoides and Trichostrongylus

Eating poorly cooked pork can lead to an infection with: A. Taenia solium and Trichinella spiralis B. Taenia saginata and Hymenolepis nana C. Trichuris trichiura and Hymenolepis diminuta D. Diphyllobothrium latum and Ascaris lumbricoides

An operculated cestode egg that can be recovered from human feces is: A. Clonorchis sinensis B. Diphyllobothrium latum C. Paragonimus westermani D. Dipylidium caninum

The adult tapeworm of Echinococcus granulosus is found in the intestine of: A. Dogs B. Sheep C. Humans D. Cattle

In infections with Taenia solium, humans can serve as the: A. Definitive host B. Intermediate host C. Either the definitive or the intermediate host D. None of these options

Humans acquire infections with Diphyllobothrium latum adult worms by: A. Ingestion of freshwater crabs B. Skin penetration of cercariae C. Ingestion of water chestnuts D. Ingestion of raw freshwater fish

Humans can serve as both the intermediate and definitive host in infections caused by: A. Enterobius vermicularis B. Hymenolepis nana C. Schistosoma japonicum D. Ascaris lumbricoides

Babesia has been implicated in disease from both splenectomized and nonsplenectomized patients. Morphologically, the parasites resemble: A. Plasmodium falciparum rings B. Leishmania donovani amastigotes C. Trypanosoma cruzi trypomastigotes D. Microsporidial spores

Organisms (and infections) that under normal conditions cannot be transmitted in the laboratory are: A. Cryptosporidium—cryptosporidiosis B. Taenia solium—cysticercosis C. Ascaris lumbricoides—ascariasis D. Enterobius vermicularis—pinworm infections

Toxoplasma gondii is characterized by: A. Possible congenital infection and ingestion of oocysts B. Cosmopolitan distribution and possible difficulties with interpretation of serological results C. Neither A nor B D. Both A and B

Oocysts of Cryptosporidium spp. can be detected in stool specimens using: A. Modified Ziehl–Neelsen acid-fast stain B. Gram stain C. Methenamine silver stain D. Trichrome stain

Which microfilariae are usually not found circulating in the peripheral blood? A. Brugia malayi B. Wuchereria bancrofti C. Onchocerca volvulus D. Loa loa

Massive hemolysis, blackwater fever, and central nervous system involvement are most common with: A. Plasmodium vivax B. Plasmodium falciparum C. Plasmodium ovale D. Plasmodium malariae

Organisms that should be considered in a nursery school outbreak of diarrhea include: A. Endolimax nana, Giardia lamblia, and Entamoeba coli B. Giardia lamblia, Dientamoeba fragilis, and Cryptosporidium spp. C. Cryptosporidium spp., Trichomonas vaginalis, and Entamoeba coli D. Pentatrichomonas hominis, Dientamoeba fragilis, and Endolimax nana

The incorrect match between disease and symptoms is: A. Paragonimiasis—hemoptysis B. Cryptosporidiosis—watery diarrhea C. Toxoplasmosis in compromised host—central nervous system symptoms D. Enterobiasis—dysentery

The formalin–ether (ethyl acetate) concentration procedure for feces is used to demonstrate: A. Motility of helminth larvae B. Protozoan cysts and helminth eggs C. Formation of amoebic pseudopods D. Trophozoites

Cysts of Iodamoeba bütschlii typically have: A. Chromatoidal bars with rounded ends B. A heavily vacuolated cytoplasm C. A large glycogen vacuole D. Many ingested bacteria and yeast cells

The miracidial hatching test helps to demonstrate the viability of eggs of: A. Taenia species B. Schistosoma species C. Hookworm species D. Opisthorchis species

Organisms that should be considered in a waterborne outbreak of diarrheal disease include: A. Giardia lamblia and Cryptosporidium spp. B. Endolimax nana and Entamoeba histolytica C. Blastocystis hominis and Trichomonas vaginalis D. Toxoplasma gondii and Schistosoma mansoni

Fecal immunoassays have become more commonly used to diagnose infections with: A. Endolimax nana and Blastocystis hominis B. Giardia lamblia and Cryptosporidium spp. C. Ascaris lumbricoides and Trichuris trichiura D. Strongyloides stercoralis and Trichomonas vaginalis

Primary infections with the microsporidia may originate in: A. The lung B. The nervous system C. The gastrointestinal tract D. Mucocutaneous lesions

Eye infections with Acanthamoeba spp. have most commonly been traced to: A. Use of soft contact lenses B. Use of hard contact lenses C. Use of contaminated lens care solutions D. Failure to remove lenses while swimming

Select the most sensitive recovery method for Acanthamoeba spp. from lens care solutions or corneal biopsies. A. The trichrome staining method B. The use of monoclonal reagents for the detection of antibody C. The use of non-nutrient agar cultures seeded with Escherichia coli D. The Giemsa’s stain method

The microsporidia are protozoans (now classified with the fungi) that have been implicated in human disease primarily in: A. Immunocompromised patients B. Pediatric patients under the age of 5 years C. Adult patients with congenital immunodeficiencies D. Patients who have been traveling in the tropics

When staining Cystoisospora belli oocysts with modified acid-fast stains, the important difference between these methods and the acid-fast stains used for acid-fast bacilli (AFB) is: A. The staining time is much longer with regular AFB acid-fast stains B. The decolorizer is weaker than acid alcohol used for AFB decolorizing C. A counterstain must be used for the modified methods D. The stain is more concentrated when staining for AFB

The incorrect match between symptoms and disease is: A. Dysentery—amebiasis B. Malabsorption syndrome—giardiasis C. Cardiac involvement—chronic Chagas disease D. Myalgias—trichuriasis