Final Finalsss Flashcards by Tatiana Perez

A physician inquiry about repeated sputum specimens, negative on routine bacterial culture, that are reported to contain only normal oropharyngeal flora on routine bacterial culture. The patient is a 67-year- old man who smokes 15 to 20 cigarettes a day and persistent cough, malaise, and a fever of 102-105°F. Empiric antimicrobial therapy and the cough and fever persist. The most recent direct Gram’s stain of sputum shows 3+ PMNs, mucus present, and rare epithelial cells. A likely etiologic agent is?

a. Haemophilus influenzae
b. Legionella pneumophila
c. Pseudomonas aeruginosa
d. Streptococcus pneumoniae

Legionella pneumophila

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Anaerobic gram-positive bacilli with subterminal spores were recovered from several blood
cultures obtained from a patient diagnosed with a malignancy of the colon. The following
results were recorded: Indole = Neg Urease = Neg Lipase = Neg Catalase = Neg Lecithinase
= Neg Growth on blood agar = Swarming colonies What is the correct identification?
a. Clostridium sordellii
b. Clostridium septicum
c. Clostridium perfringens
d. Propionibacterium acnes

Clostridium septicum

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Which of the following is NOT true about Chlamydia pneumoniae?
I. Common agent of lower respiratory tract infection
II. Humans become infected from animal reservoirs.
III. High risk for patients with nerve ending damages
IV. Hep 2 cell culture and Macro-immunofluorescence
a. II, IV
b. I, III
c. II, III
d. I, IV

I, III

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Gram negative coccobacilli was isolated from ear discharge after 48 hours of incubation
on Horse Blood agar plate. The isolates were positive on ornithine and Urea tests. What
most likely is the organism?
a. H. Parainfluenzae Biotype II
b. H. Haemolyticus Biotype I
c. H. influenzae Biotype I
d. H. parahaemolyticus Biotype IV
e. H. ducreyi Biotype III

H. influenzae Biotype I

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Anaerobic gram-positive, spore-forming bacilli were recovered from the feces of a
chemotherapy patient with severe diarrhea. The patient had undergone antibiotic therapy 1
week prior. The fecal culture produced growth only on the CCFA plate. No aerobic growth
of normal flora was seen after 48 hours.
The following results were noted:
Kanamycin = Sensitive Vancomycin = Sensitive Colistin = Resistant
Lecithinase = negative Lipase = negative Nitrate = negative
Indole = colorless ring Urease = orange Catalase = Neg
Spores = positive
Colonial morphology
CCFA agar = Growth of yellow, “ground-glass” colonies that fluoresce chartreuse (yellow-green)

A. Clostridium sordellii
B. Clostridium tetani
C. Clostridium difficile
D. Clostridium perfringens

Clostridium perfringens

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Egg yolk agar is used to detect which enzyme produced by Clostridium species?
a. β-Lactamase
b. Lecithinase
c. Catalase
d. Oxidase

Lecithinase

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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. Oxidase
b. Hemin
c. Indole
d. NAD

NAD

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Which mechanism is responsible for botulism in infants caused by Clostridium botulinum?
a. Virulence of the organism
b. Ingestion of preformed toxin in food
c. Lipase activity of the organism
d. Ingestion of spores in food or liquid

Ingestion of spores in food or liquid

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Francisella tularensis is the bacterium that causes tularemia, a disease not uncommonly
seen in hunters. Which of the following statements best characterizes this bacterium?

A. It produces at least one protein toxin consisting of two subunits. A and R, that causes severe spasmodic
cough usually in children.
B. It secretes erythrogenic toxin that causes the characteristic signs of scarlet fever. Strep. pyogenes
C. It secretes exotoxin that has been called “verotoxin” and ‘Shiga-like toxin”; Infection is mediated by a specific attachment to mucosal Membranes.
D. It requires cysteine for growth
E. It produces toxin that blocks protein synthesis in an infected cell and carries a lytic bacteriophage that
produces the genetic information for toxin production.

It requires cysteine for growth

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Anaerobic gram-positive diphtheroids , non-spore formers were cultured from two separate
blood culture bottles (at 5 days) obtained from a 25-year-old patient admitted to the
hospital with dehydration, diarrhea, and other flulike symptoms. Four other blood culture
bottles did not grow any organisms at 7 days and were discarded. The following results
were obtained from the recovered anaerobe: positive in Indole, Nitrate, and Catalase test.
Susceptible in Susceptible in kanamycin and vancomycin while resistant in Colistin. What
is the correct identification?
a. Eubacterium lentum
b. Actinomyces spp.
c. Propionibacterium acnes
d. Peptostreptococcus spp.

Propionibacterium acnes

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All of the following genera are anaerobic cocci that stain gram positive except:
a. Peptostreptococcus spp.
b. Streptococcus spp.
c. Peptococcus spp.
d. Veillonella spp.

Veillonella spp.

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Identify the Haemophilus species:
Requirement for X factor: positive
Requirement for V factor. positive
Hemolysis: negative
ALA: negative
Fermentation of glucose: positive
Fermentation of sucrose: negative
Fermentation of lactose: negative
Fermentation of fructose: negative
A. H. influenzae
B. H. parahaemolyticus
C. H. ducreyi
D. H. Parainfluenzae
E. H. Haemolyticus

H. influenzae

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Detection of antibody against cardiolipin is useful for the diagnosis of which of the
following disease?
A. Relapsing fever
B. Lyme disease
C. Leptospirosis
D. Syphilis

Syphilis

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Haemophilus influenzae causes ocular infections and requires X and V factors in the
primary medium for growth. The subspecies Haemophilus influenza biogroup aegyptius
can further be identified and differentiated by which two tests?
a. Indole and xylose
b. Oxidase and catalase
c. ALA test and oxidase
d. Glucose and urease

Indole and xylose

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The causative agent of endemic or murine typhus is
A. Rickettsia conorii
B. Rickettsia typhi
C. Rickettsia akari
D. Rickettsia prowazekii

Rickettsia typhi

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Rocky Mountain Spotted fever is transmitted by the bite of a tick infected with.
a. Rickettsia prowazekii
b. Rickettsia conorii
c. Rickettsia rickettsii
d. Rickettsia akari

Rickettsia rickettsii

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Which gram-negative bacilli produce black pigment and brick red fluorescence when
exposed to an ultraviolet light source?
a. Bacteroides spp. and Fusobacterium spp.
b. Porphyromonas spp. and Prevotella spp.
c. Fusobacterium spp. and Actinomyces spp.
d. All of these options

Porphyromonas spp. and Prevotella spp.

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A gram-negative coccobacillus was isolated from upper respiratory tract sections with
these biochemical reactions: Hemin factor: no growth; NAD factor with growth, with red
end-colored in fermentation of mannose and mannitol, and colorless at ONPG
a. H. Parainfluenzae
b. H. influenzae
c. H. ducreyi
d. H. parahaemolyticus
e. H. Haemolyticus

H. parahaemolyticus

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The diagnosis of Lyme disease can be made by:
A. silver impregnation techniques to demonstrate spirochete in tissue
B. serological demonstration of antibody in patient’s serum using enzyme immunoassay
C. growth on blood and chocolate agar
D. both A and B
E. all of the above

all of the above

rationale: in stages I and II of Lyme disease, EIA testing is performed on serum for antibodies. PCR testing and culture of Borrelia spp. are performed on a skin biopsy. In stage III, synovial fluid, skin biopsy, and CSF are tested for Borrelia spp. by PCR

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The mild type of typhus fever that is caused by recrudescence of an initial attack of
epidemic typhus is known as:
a. Brill-Zinsser disease
b. Q fever
c. Tsutsugamushi disease
d. Relapsing fever

Brill-Zinsser disease

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Identify the following bacterium and specimen pairing that is mismatched (specimen not
appropriate for isolation).
a. Chlamydia trachomatis: first voided urine
b. Chlamydia psittaci: fecal swab
c. Chlamydia trachomatis: endocervical swab
d. Chlamydia pneumonia: throat swab or sputum

Chlamydia psittaci: fecal swab

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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. Porphyromonas spp.
d. Prevotella spp

Fusobacterium spp.

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An elderly woman who cared for several domestic cats was hospitalized with suspected
cat-scratch disease. Blood cultures appeared negative, but a small, slightly curved
pleomorphic gram-negative bacillus grew on BHI agar. What is the most likely
identification?
a. Haemophilus spp.
b. Bartonella spp.
c. Kingella spp.
d. Brucella spp.

Bartonella spp.

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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. Prevotella spp.
b. Bacteroides spp.
c. Fusobacterium spp.
d. Porphyromonas spp.

Bacteroides spp.

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The δ-ALA test is a confirmatory procedure for which test used for identification of Haemophilus species? a. V factor requirement b. Urease production c. Indole production d. X factor requirement

X factor requirement

A Porphyromonas spp. a. Bacteroides spp. b. Prevotella spp. c. Fusobacterium spp

Fusobacterium spp

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

b capsular serotypes

Borrelia burgdorferi, a spirochete transmitted by Ixodes dammini and the etiologic agent of? a. Q fever b. Lyme disease c. Relapsing fever d. Rat-like fever

Lyme disease

A gram positive, spore-forming bacillus growing on blood agar anaerobically produces a double zone of beta hemolysis and is positive for lecithinase. What is the presumptive identification of this isolate? a. Clostridium difficile b. Bacteroides urealyticus c. Bacteroides fragilis d. Clostridium perfringens

Clostridium perfringens

During the first week of leptospirosis, the most reliable way to detect the presence of the causative agent is by the direct I. culturing blood II. culturing urine III. Examination of blood IV. Examination of CSF A. I, III B. IV only C. II D. I only

I only

Which of the following plates should be used in order to identify Haemophilus haemolyticus and Haemophilus parahaemolyticus? a. Sheep blood agar and chocolate agar b. Brain–heart infusion agar with sheep red cells added c. Horse blood agar and Mueller–Hinton agar with X and V strips d. Chocolate agar and Mueller–Hinton agar with X factor added

Horse blood agar and Mueller–Hinton agar with X and V strips

A direct smear of a specimen for aerobic and anaerobic culture revealed the presence of gram positive rods. A blood agar plate was inoculated and incubated in an aerobic environment and in a clinical laboratorian saw that the methylene blue strip was blue. Growth was observed in both the aerobic and anaerobic plate. Which of the following statements is most likely true? a. The isolate is most likely a strict aerobe b. The isolate is most likely facultative anaerobe c. The isolate is most likely a strict anaerobe d. Cannot be determined; the methylene blue was blue and this indicates that oxygen is present in the anaerobic jar

Cannot be determined; the methylene blue was blue and this indicates that oxygen is present in the anaerobic jar

Which of the following is not correct about spirochetes? I. Motility is via axial filaments II. They are visualized both in dark field and phase optics III. Spirochetes are gram positive IV. Those humans with disease are 0.1-0.5 um in diameter and 5-30um in length A. II, IV B. II, III C. III, IV D. I, III

III, IV

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–Gengou, and Regan–Lowe (with 10% charcoal) agars. All media grew a gramnegative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? a. Bordetella bronchiseptica b. Bordetella pertussis c. Haemophilus influenza d. Haemophilus parainfluenzae

Bordetella pertussis

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

Propionibacterium acnes

Which Haemophilus species is difficult to isolate and recover from genital ulcers and swollen lymph nodes? a. H. haemolyticus b. H. ducreyi c. H. parahaemolyticus d. H. aphrophilus

H. ducreyi

A small, gram-negative coccobacillus recovered from the blood samples of a 2-year-old child gave the following results: Indole = red ring Glucose = positive X requirement = no growth V requirement = with growth Nitrate reduction= red Lactose = Negative Sucrose = positive ALA= reddish orange Hemolysis= Negative Which is the most likely identification? A. Haemophilus influenzae B. Haemophilus ducreyi C. Haemophilus parahaemolyticus D. Haemophilus parainfluenzae

Haemophilus parainfluenzae

A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results: Catalase = with effervescence Oxidase = purple Motility = turbid Hippurate hydrolysis = purple Growth at 42°C = positive Growth at 25C = negative Nalidixic acid = Susceptible Pigment = Negative Cephalothin = Resistant Urease: orange The most likely identification is: a. Campylobacter fetus b. Campylobacter jejuni c. Pseudomonas putida d. Pseudomonas aeruginosa

Campylobacter jejuni

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

Urease, nitrate, and hippurate hydrolysis

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

Actinobacillus

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

Indole

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

Sheep blood agar

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

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

Biphasic Castenada bottles with Brucella broth

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

Cysteine and cystine

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

Buffered charcoal–yeast extract (CYE) agar

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

Chocolate agar

Haemophilus influenzae causes ocular infections (pinkeye) and requires X and V factors in the primary medium for growth. Te 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

Indole and xylose

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

NAD

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

H. aphrophilus

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

Production of β-lactamase enzymes

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. Te 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

Francisella tularensis

A suspected case of Legionnaires’ disease was noted on the request form for a culture and sensitivity ordered on a sputum sample. Te 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

Direct immunofluorescent microscopy

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

Decreased O2

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

Kanamycin–vancomycin (KV) agar

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

Urinary tract infections

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 options

All of these options

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

Round, terminal spores

Te 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

Preformed toxin in food

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

C. difficile

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

B. ureolyticus

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

C. perfringens

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

Serological analysis

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

Borrelia burgdorferi

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.

Borrelia spp.

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

Mycoplasma pneumoniae

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

Mycoplasma hominis

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

Ureaplasma urealyticum

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

PCR molecular testing

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

EIA testing and direct antigen testing

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

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

Blood, CSF, and skin biopsy

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

Gas–liquid chromatography (GLC)

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

Prereduced peptone–yeast extract–glucose (PYG)

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

Toxin neutralization