MICRO by MR. BIRAQUIT Flashcards by Dead Braincells

An 8 year old boy develops a severe sore throat. On examination, a grayish white exudate is seen on the tonsils and pharynx. The differential diagnosis includes group A streptococcal infection and severe adenovirus infection. The possible cause of the boy’s pharyngitis is most likely:

A. A catalase (-), gram (+) coccus that grows in chain
B. A single stranded positive sense RNA virus
C. A catalase (+), gram (+) coccus that grows in clusters
D. A catalase (-), gram (+) bacillus

A catalase (-), gram (+) coccus that grows in chain

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A primary mechanism responsible for the pathogenesis of the boy’s disease is:

A. A net increase in intracellular cyclic adenosine monophosphate
B. Action of M protein
C. Action of IgA1 protease
D. Action of enterotoxin A

Action of M protein

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Significant yellow colonies isolated from primary culture of a urine sample were subcultured on Mannitol Salt Agar (MSA). Colonies on MSA are shown in the picture. What is the most likely isolate?

What test can be used to confirm the identification of the isolated organism?

If S. aureus or S. saprophyticus were suspected to be isolated from the sample, what test can be used to differentiate the two organism?

S. aureus

Coagulase test

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A 40 year old woman develops severe headache and fever. A brain scan shows a ring-enhancing lesion of the left hemisphere. During surgery, a brain abscess is found. Culture of the abscess fluid grows a catalase (-), gram (+) coccus that on gram stain is in pairs and chains. The organism is B-hemolytic and forms very small colonies. It agglutinates with group B antisera. The organism most likely:

A. Streptococcus pyogenes
B. Enterococcus faecalis
C. Streptococcus agalactiae
D. Streptococcus anginosus group

Streptococcus agalactiae

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Enterococci can be distinguished from noneterococcal group D on the basis of which of the following characteristics?

A. y-hemolysis
B. Esculin hydrolysis
C. Growth in 6.5% NaCl
D. Growth in the presence of Bile

Growth in 6.5% NaCl

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A 22-year-old woman who works in a plant nursery presents with a history of fever and cough for 2 months. Over this period of time she has lost 5 kg. Chest radiography shows bilateral upper lobe infiltrates with cavities. Her sputum smear shows acid-fast bacilli. The likely means by which the patient acquired her infection is

A. Sexual activity
B. Ingesting the microorganisms in her food
C. Holding onto contaminated handrails when she takes public transportation.
D. Handling potting soil
E. Breathing aerosolized droplets containing the
microorganism

Breathing aerosolized droplets containing the microorganism

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Lysostaphin susceptibility is a test used to
differentiate:

A. Staphylococcus spp. from Streptococcus spp.
B. Staphylococcus spp. from Enterococcus spp.
C. Staphylococcus spp. from Micrococcus spp.
D. Streptococcus spp. from Micrococcus

Staphylococcus spp. from Micrococcus spp.

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The blood bank reports that samples of banked blood stored at refrigerator temperature have become contaminated with nonfermentative gram-negative bacilli. The organisms known to be implicated in such cases are:

A. Alcaligenes faecalis and Alcaligenes odorans
B. Acinetobacter calcoaceticus and
Acinetobacter iwoffi
C. Pseudomonas fluorescens and Pseudomonas putida
D. Burkholderia cepacia and Pseudomonas stutzeri
E. Burkholderia mallei and Aggregatibacter aphrophilus

Pseudomonas fluorescens and Pseudomonas putida

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Characteristically, species from the genus
enterococcus are:

A. Unable to grow in 6.5% NaCl
B. Bile esculin positive
C. Sensitive to Penicillin
D. Sodium hippurate negative

Bile esculin positive

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Alpha-hemolytic streptococci recovered from a wound were found to be Penicillin resistant. The organism shows the following reactions:
BILE ESCULIN (+);
6.5% NaCl (+);
PYR (+);
SXT (Resistant).
What is the most likely identification?

A. Group B streptococcus
B. Streptococcus bovis
C. Streptococcus pneumoniae
D. Enterococcus faecalis
E. Streptococcus anginosus

Enterococcus faecalis

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An enterococcus isolated from multiple blood
cultures in a patient with endocarditis should be:

A. Screened for high level Aminoglycoside
resistance
B. Checked for tolerance
C. Assayed for serum antimicrobial activity
D. Tested for beta-lactamase production
E. Tested with capsular swelling test.

Screened for high level Aminoglycoside
resistance

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The Quellung test is used to identify which
Streptococcus spp.?

A. Streptococcus pyogenes
B. Streptococcus agalactiae
C. Streptococcus sanguis
D. Streptococcus pneumoniae

Streptococcus pneumoniae

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Nutritionally variant Streptococci (NVS) require specific thiol compounds, cysteine or the active form of Vitamin B6. Which of the following supplies these requirements?

A. Bacitracin disk test
B. Staphylococcal cross-streak
C. CAMP test
D. Bile solubility test
E. Cysteine tryptic agar

Staphylococcal cross-streak

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A sputum sample from a patient with pneumonia
produced many colonies of gram-negative
diplococci on chocolate agar that were also
present in fewer numbers on Modified Thayer Martin medium after 48 hours. Biochemical reactions results are:
CATALASE (+);
OXIDASE (+);
DNASE (+);
GLUCOSE (0);
MALTOSE (0);
SUCROSE (0);
FRUCTOSE (0).
What is the most likely
identification?

A. Moraxella catarrhalis
B. Neisseria sicca
C. Neisseria flavescens
D. Pnatoea agglomerans
E. Hemophilus influenzae

Moraxella catarrhalis

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Which of the following is the specimen of choice
for detecting Rotavirus?

A. Throat swab
B. Bronchoalveolar wash
C. Feces sample
D. Urine sample

Feces sample

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Germ tube formation is seen with which two
yeasts?

A. Candida albicans and Candida tropicalis
B. Candida albicans and Candida parapsilosis
C. Candida albicans and Candida glabrata
D. Candida albicans and Candida dubliniensis

Candida albicans and Candida dubliniensis

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Which of the following correctly describes
Staphylococci?

A. Susceptible to 0.04 units Bacitracin
B. Produces oxidase enzyme
C. Susceptible to furazolidone
D. Can not ferment mannitol
E. Resistant to Lysostaphin

Can not ferment mannitol

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An organism is a late or slow lactose fermenter
possesses:

A. Beta-galactosidase and lactose permease
B. Beta-galactosidase only
C. Lactose permease only
D. Neither beta-galactosidase nor lactose
permease

Beta-galactosidase only

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An isolate of E.coli recovered from stool of a
patient with severe bloody diarrhea should be tested for what sugar before sending to a
reference laboratory for serotyping?

A. Sorbitol
B. Mannitol
C. Raffinose
D. Sucrose
E. Inositol

Sorbitol

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Which of the following organisms is often
confused with Salmonella spp. biochemically
and on plated media?

A. Escherichia coli
B. Enterobacter cloacae
C. Citrobacter freundii
D. Shigella dysenteriae
E. Morganella morganii

Citrobacter freundii

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A Staphylococcus produced a fibrin clot in
the tube coagulase test, but not in the slide
coagulase test. This organism:

A. Produces only free coagulase and is most
likely S.aureus
B. Produces only bound coagulase and is
most likely S.aureus
C. Is most likely S.epidermidis because of
the negative slide test
D. Is most likely S.epidermidis since the
slide test is unrealible

Produces only free coagulase and is most
likely S.aureus

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Bacitracin A disks (0.04 units) are used for
the presumptive identification of which
group of beta-hemolytic Streptococcus?

A. Group A
B. Group B
C. Group C
D. Group D
E. Group F

Group A

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A small, gram-negative coccobacillus recovered from CSF of a 2-year old child gave the following results:
X disk (+) Glucose (+)
V disk (+) Sucrose (-)
Indole (+) Lactose (-)
Urease (+) Hemolysis (-)

Which is most likely identification?

A. Hemophylus parainfluenzae
B. Hemophylus ducreyi
C. Hemophilus influenzae
D. Hemophilus aphrophilus

Hemophilus influenzae

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Which is not a characteristic of Vibrio
cholerae?

A. Motile with single polar flagellum
B. Oxidase negative
C. Ferments glucose and sucrose
D. Positive string test
E. Resistant to bile salts

Oxidase negative

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The presence of clue cells in vaginal smears is diagnostic with an infection caused by: A. Campylobacter jejuni B. Gardnerella vaginalis C. Aeromonas hydrophila D. Candida albicans E. Trichomonas vaginalis

Gardnerella vaginalis

Complications that result from Streptococcus pyogenes infections are the poststreptococcal diseases: A. Meningitis and glomerulonephritis B. Rheumatic fever and acute glomerulonephritis C. Rheumatoid arthritis and anemia D. Pyelonephritis and glomerulonephritis E. Lupus erythematosus and meningitis

Rheumatic fever and acute glomerulonephritis

Two blood cultures on a newborn grew beta-hemolytic Streptococci with the following reactions: Bacitracin (Resistant) PYR (-) SXT (Resistant) Bile solubility (-) CAMP test (+) 6.5% NaCl (+) What is the most likely identification? A. Group A Streptococci B. Group B Streptococci C. Group C Streptococci D. Group D Streptococci

Group B Streptococci

A college student attended a beach party where raw oysters and other shellfish were consumed. The next day, he had symptoms of septicemia. The blood cultures grew gram negative bacilli with the following characteristics: OXIDASE (+); Mac Conkey agar: Pink colonies The most likely organism is: A. Pseudomonas aeruginosa B. Serratia marcescens C. Vibrio vulnificus D. Acinetobacter baumanii E. Enterococcus faecalis

Vibrio vulnificus

Which test is used to differentiate the Viridans Streptococci from group D Streptococci? A. Bacitracin disk test B. CAMP test C. Hippurate hydrolysis test D. Bile esculin test E. Neufeld Quellung reaction

Neufeld Quellung reaction

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

Enterococcus faecalis

What is the ideal specimen for the recovery of Bordetella pertussis? A. Nasopharyngeal swab B. Cough plate C. Urine D. Pleural fluid E. Buccal swab

Nasopharyngeal swab

A 23-year-old woman has a history of recurrent urinary tract infections, including at least one episode of pyelonephritis. Blood typing shows the P blood group antigen. Which of the following is likely to be the primary cause of her infections? A. Escherichia coli that produce heat-stable toxin B. Escherichia coli with K1 (capsular type 1) antigen C. Escherichia coli O139 (lipopolysaccharide O antigen 139) D. Escherichia coli with P-pili (fimbriae) E. Escherichia coli O157:H7

Escherichia coli with P-pili (fimbriae)

Which of the following best describes the mechanism of action of diphtheria toxin? A. Forms pores in red blood cells causing hemolysis B. Degrades lecithin in eukaryotic cell membranes C. Causes release of tumor necrosis factor D. Inhibits protein synthesis elongation factor 2 (EF-2) E. Causes increased adenylate cyclase activity

Inhibits protein synthesis elongation factor 2 (EF-2)

Which of the following is most likely to be associated with the formation of a bacterial biofilm? A. Airway colonization in a cystic fibrosis patient with a mucoid (alginate+) strain of Pseudomonas aeruginosa B. Urinary tract infection with E.coli C. Meningitis with Neisseria meningitidis D. Tetanus E. Purulent impetigo caused by Staphylococcus aureus

Airway colonization in a cystic fibrosis patient with a mucoid (alginate+) strain of Pseudomonas aeruginosa

Rapid assay useful for the detection of Legionella spp is: A. Bacterial culture B. Gram staining C. Urine antigen detection and DFA D. Indirect fluorescent assay (IFA) E. Broth microdilution assay

Urine antigen detection and DFA

Dangerous and exotic agents which pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease is classified as: A. BSL 1 B. BSL 2 C. BSL 3 D. BSL 4

BSL 4

Gram positive bacilli that cause occupational disease of butchers, meat processors, farmers, poultry workers, fish handlers, and veterinarians: A. Bacillus cereus B. Listeria monocytogenes C. Erysipelothrix rhusiopathiae D. Bacillus subtilis

Erysipelothrix rhusiopathiae

Streptococcus pneumoniae and viridans Streptococci can be differentiated by: A. Optochin disk test B. Bacitracin disk test C. CAMP test D. Bile esculin test

Optochin disk test

Which one of the following is an important virulence factor of Bacillus anthracis? A. Protective antigen and Lethal factor B. Lipopolysaccharide C. Pili and Lecithinase D. A toxin that inhibits peptide chain elongation factor EF-2

Protective antigen and Lethal factor

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

Streptococcus pneumoniae colonies on Blood agar plate.

A food commonly associated with Bacillus cereus food poisoning is: A. Fried rice B. Baked potato C. Hot freshly steamed rice D. Green beans E. Honey

Fried rice

A 45-year-old man who immigrated to the United States 5 years ago sustained a puncture injury to the lower part of his right leg when his rotary lawn mower threw a small stick into his leg. Six days later, he noticed spasms in the muscles of his right leg. On day 8, he had generalized muscle spasms, particularly noticeable in the muscles of his jaw. He was unable to open his jaw and came to the emergency department. Suddenly he has general muscle spasm with arching of his back. The correct diagnosis is which of the following? A. Botulism B. Anthrax C. Gas gangrene D. Tetanus E. Toxic shock syndrome

Tetanus

Which of the following food items is most frequently associated with infant botulism? A. Corn syrup B. Canned infant formula C. Liquid multivitamins D. Honey E. Jarred baby food

Honey

All of the following statements regarding Clostridium perfringens are correct except: A. It produces an enterotoxin. B. It produces a double zone of β-hemolysis when grown on blood agar. C. It is the most common cause of antibiotic-associated diarrhea. D. It can cause intravascular hemolysis.

It is the most common cause of antibiotic-associated diarrhea.

Abiotrophia and Granulicatella will not grow on blood agar or chocolate agar unless it is supplied with: A. Pyridoxal (vitamin B6) B. Hematin C. NAD D. Thiamine

Pyridoxal (vitamin B6)

An infant has been diagnosed with bacterial meningitis. Further testing of the CSF would likely indicate: A. Increased WBC with predominance of lymphocytes, decreased glucose, increased protein. B. Increased WBC with predominance of neutrophils, increased glucose and protein C. Increased WBC with predominance of neutrophils, increased protein, decreased glucose D. Decreased WBC with predominance of neutrophils, increased protein, decreased glucose

Increased WBC with predominance of neutrophils, increased protein, decreased glucose

An 11-year-old boy develops a mild fever and pain in his upper arm with a lytic lesion. He is taken to surgery, where the lesion is debrided. Culture from the lesion yields gram-positive cocci. The test shows that the organism is a Staphylococcus and coagulase positive. Based on this information, you know the organism is: A. Susceptible to nafcillin B. β-Lactamase-positive C. A producer of protein M D. Encapsulated E. Catalase positive

Catalase positive

A 65-year-old man develops an abscess on the back of his neck. Culture yields S aureus. The isolate is tested and found to be positive for the mecA gene, which means that: A. The isolate is resistant to vancomycin. B. The isolate is resistant to nafcillin. C. The isolate is resistant to clindamycin. D. The isolate is resistant to erythromycin

The isolate is resistant to nafcillin

Gram negative diplococci are isolated from a female genital tract. Which of the following is the most appropriate action? A. Report “Neisseria gonorrheae isolated” and perform susceptibility test. B. Report the amount of “gram-negative diplococci” and the number of neutrophils present. C. Report “normal flora isolated” and discard specimen D. Plate the specimen in blood agar plate

Report the amount of “gram-negative diplococci” and the number of neutrophils present.

Waterhouse-Friderichsen syndrome is associated with: A. Autoimmune response to group A streptococcal infection. B. Septicemia from Neisseria gonorrheae infection. C. Hemolytic reaction from Staphylococcus aureus infection. D. Adrenal hemorrhage from Neisseria meningitidis infection

Adrenal hemorrhage from Neisseria meningitidis infection

Which of the following statements regarding the role of protein A in the pathogenesis of infections caused by S aureus is correct? A. It is responsible for the rash in toxic shock syndrome. B. It converts hydrogen peroxide into water and oxygen. C. It is directly responsible for lysis of neutrophils. D. It is a bacterial surface protein that binds to the Fc portion of IgG1

It is a bacterial surface protein that binds to the Fc portion of IgG1

Pili antigens are associated with: A. Neisseria gonorrheae B. Streptococcus pyogenes C. Bacillus subtilis D. Mycoplasma pneumoniae

Neisseria gonorrheae

Cultures obtained from a dog bite produced yellow, tan, and slightly pink colonies on blood agar and chocolate agar with a margin of fingerlike projections appearing as film around the colonies. Given the following results at 24 hours, which is the most likely organism? OXIDASE (-) CATALASE (-) MOTILITY: (+) Gliding appearance Mac conkey agar: No growth A. Capnocytophaga B. Actinobacillus C. Eikenella D. Pseudomonas

Capnocytophaga

Clostridium difficile is most commonly identified by: A. Demonstration of cytotoxin B. Identification of C. difficile antigen C. Isolation of organism from tissue culture D. Demonstration of lecithinase

Demonstration of cytotoxin

Which of the following is not a characteristic of Corynebacterium diphtheriae? A. Pleomorphic morphology B. Gram positive bacillus C. Spore former D. Nonmotile

Spore former

An antibiotic that inhibits cell wall synthesis is: A. Chloramphenicol B. Penicillin C. Sulfamethoxazole D. Ciprofloxacin E. Cotrimoxazole

Penicillin

Food poisoning due to Clostridium botulinum is often caused by? A. Contaminated poultry products B. Inhalation of spores C. Improperly home-canned foods D. Dairy products and custards E. Contaminated poorly-cooked seafoods

Improperly home-canned foods

In the Kirby-Bauer disc diffusion susceptibility test, which variable is critical when testing Pseudomonas spp. for antibiotic susceptibility to aminoglycosides? A. Incubation temperature B. Duration of incubation C. Cation content of media D. Depth of agar

Cation content of media

On Potassium tellurite medium, Corynebacterium diphtheriae produces: A. Beta-hemolytic colonies B. Enhanced pleomorphic properties C. Black colonies D. Pink to red colonies

Black colonies

Which of the following organism is DNAse positive? A. Neisseria gonorrheae B. Moraxella catarrhalis C. Klebsiella oxytoca D. Campylobacter jejuni

Moraxella catarrhalis

A gram positive bacillus isolated from the spinal fluid of a 1-month old infant is catalase positive, beta hemolytic, and bile esculin positive, and exhibits tumbling motility in a wet preparation. This organism is most likely: A. Lactobacillus acidophilus B. Corynebacterium jeikeium C. Erysipelothrix rhusiopathiae D. Listeria monocytogenes

Listeria monocytogenes

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 E. Taxo P

D-zone test

Sputum samples for TB culture may contain normal flora and other contaminating microorganisms, so samples must be: A. Digested with N-acetyl-L-cysteine B. Decontaminated with 2% NaOH C. Digested with trisodium phosphate D. Decontaminated with dithiothreitol

Decontaminated with 2% NaOH

Which of the following is noted for a positive result for Niacin accumulation? A. Mycobacterium tuberculosis B. Mycobacterium avium-intracellulare complex C. Mycobacterium fortuitum-chelonae complex D. Mycobacterium gordonae

Mycobacterium tuberculosis

The superoxol test is used as presumptive test for: A. Neisseria gonorrheae B. Neisseria lactamica C. Gardnerella vaginalis D. Lactobacillus spp. E. Enterococcus faecium

Neisseria gonorrheae

The single most important method for classifying and speciating streptococci is: A. Biochemical testing B. Hemolytic properties (α-, β-, nonhemolytic) C. Capsular swelling (quellung) reaction D. None of the above

None of the above

Resistance to Clindamycin can be induced in vitro by: A. Ampicillin B. Erythromycin C. Gentamycin D. Penicillin E. Oxacillin

Erythromycin

Which of the following viral families are associated with reactivation of latent infections? A. Hepatitis viruses B. Influenza viruses C. Parvoviruses D. Herpesviruses E. HIV

Herpesviruses

Cultivation of this fungal organism, such as from a positive blood culture, requires an agar medium overlaid with a long-chain fatty acid (olive oil) A. Cryptococcus neoformans B. Coccidioides immitis C. Malassezia furfur D. Candida tropicalis E. Aspergillus flavus

Malassezia furfur

Vaginal swab culture on modified Thayer-Martin medium produced several colonies of gram negative diplococci that were catalase and oxidase positive and superoxol negative. Given the following carbohydrate reaction, select the most likely identification: Glucose (+) Maltose (+) Lactose (+) Sucrose (-) A. Neisseria gonorrheae B. Neisseria meningitidis C. Neisseria lactamica D. Neisseria sicca E. Moraxella catarrhalis

Neisseria lactamica

Which statement correctly describes the antigens of Enterobacteriaceae? A. The O antigen is heat labile. B. The O antigen is located on the cell wall. C. The Vi antigen is a flagellar antigen. D. The K antigen is the somatic antigen.

The O antigen is located on the cell wall.

Which of the following viruses is implicated along with Epstein-Barr virus as a cause of Infectious mononucleosis? A. Cytomegalovirus B. Coxsackie A virus C. Coxsackie B virus D. Hepatitis B virus E. All of the above

Cytomegalovirus

Cultures for Brucella should be incubated in 5%-10% CO2 in a humidified atmosphere; inoculated plates are incubated for up to ______ before they are considered negative and discarded. A. 5 days B. 1 week C. 2 weeks D. 3 weeks

3 weeks

Which of the following sets of tests best differentiates Salmonella and Citrobacter species? A. KCN, malonate, beta-galactosidase, Lysine decarboxylase B. Dulcitol, citrate, indole, H2S production C. Lactose, adonitol, KCN, motility D. Lysine decarboxylase, lactose, sucrose, malonate, indole

KCN, malonate, beta-galactosidase, Lysine decarboxylase

Which of the following is a cause of community-acquired atypical pneumonia, often referred to as walking pneumonia? A. Chlamydophila pneumoniae B. Streptococcus pneumoniae C. Mycoplasma hominis D. Mycoplasma pneumoniae E. Klebsiella pneumoniae

Mycoplasma pneumoniae

Which Trichophyton spp causes the favus type of tinea capitis? A. Trichophyton violaceum B. Trichophyton tonsurans C. Trichophyton schoenleinii D. All of the above

Trichophyton schoenleinii

A 37-year-old woman with a history of urinary tract infections comes to the emergency department with burning on urination along with frequency and urgency. She says her urine smells like ammonia. The cause of her urinary tract infection is likely to be: A. Proteus mirabilis B. Citrobacter freundii C. Escherichia coli D. Serratia marcescens E. Streptococcus agalactiae

Proteus mirabilis

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

Sporothrix schenckii

All members of the family Enterobacteriaceae: A. Oxidize glucose B. Ferment glucose C. Ferment lactose D. Produce urease enzyme E. All of the above.

Ferment glucose

Which of the following is the most useful morphological feature in identifying the mycelial phase of Histoplasma capsulatum? A. Arthrospores B. Microspores C. Tuberculate macroconidia D. Nonseptate macroconidia

Tuberculate macroconidia

A 64-year-old patient with lymphoma has a positive blood culture at 18 hours incubation. The organism is a nonlactose fermenting gram negative bacillus on Mac Conkey agar. Further testing gives the following reactions: OXIDASE (-) UREA (+) TSI: K/A, H2S (-) ODC (-) INDOLE (+) VP (+) CITRATE (+) PHENYLALANINE DEAMINASE (+) What is the identification? A. Morganella B. Proteus C. Providencia D. Serratia E. Klebsiella

Providencia

A 17-year old female with cystic fibrosis is diagnosed with pneumonia. A sputum sample grew gram negative bacilli with yellow, smooth colonies that have the following reactions: OXIDASE (+) TSI: K/K GLUCOSE: OXIDIZED LDC (+) The most likely organism is: A. Burkholderia cepacia B. Klebsiella pneumoniae C. Shewanella putrefaciens D. Sternotrophomonas maltophilia

Burkholderia cepacia

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

Morganella, Providencia, and Proteus

Chlamydial infections have been implicated in: A. Urethritis and conjunctivitis B. Gastroenteritis and urethritis C. Neonatal pneumonia and gastroenteritis D. Neonatal meningitis and conjunctivitis

Urethritis and conjunctivitis

The stage of Lyme disease characterized by the appearance of erythema chronicum migrans is: A. Primary B. Secondary C. Tertiary D. Latent

Primary

Characteristics of the HACEK group of bacteria include: A. Association with urinary tract infections B. Requirement of 5-10% CO2 for growth C. Pleomorphic gram-positive bacilli D. Requirement of 42C for growth

Requirement of 5-10% CO2 for growth

The Mycobacteria are described as “acid fast” because: A. The organism cannot be stained with acidic dyes B. The organisms are deeply decolorized with acid alcohol C. The organism are easily stained with acidic dyes D. Once stained, the organisms cannot be decolorized with acid alcohol

Once stained, the organisms cannot be decolorized with acid alcohol

Supplementation with Hemin and Vitamin K will enhance the recovery of A. Gram-positive cocci B. Aerobic bacteria C. Anaerobic bacteria D. Fungi

Aerobic bacteria

“Owl’s eye” cytological inclusions are characteristic of infection caused by: A. HIV B. CMV C. HSV D. VZV

CMV

When specimen delay is anticipated, virology specimens are optimally maintained: A. At room temperature B. Incubated at 35 C C. Held at 4 C and snap-frozen to -70 C D. Frozen immediately at -20 C E. Stored at 42 C oven

Held at 4 C and snap-frozen to -70 C

A 55-year-old homeless man with alcoholism presents with severe multilobar pneumonia. He requires intubation and mechanical ventilation. A Gram stain of his sputum reveals numerous polymorphonuclear leukocytes and gram-negative rods that appear to have a capsule. The organism is a lactose fermenter on MacConkey agar and is very mucoid. It is nonmotile and lysine decarboxylase positive. What is the most likely organism causing his illness? A. Enterobacter aerogenes B. Proteus mirabilis C. Klebsiella pneumoniae D. Morganella morganii E. Serratia marcescens

Klebsiella pneumoniae

The spores of Clostridium tetani are located: A. Centrally B. Subterminally C. Terminally D. Spores are absent

Terminally

Which of the following test methods is the least sensitive procedure for diagnosis of colitis caused by Shiga toxin–producing Escherichia coli? A. Culture on sorbitol MacConkey agar B. Toxin testing using an enzyme immunoassay C. Cell culture cytotoxin assay using Vero cells D. Polymerase chain reaction for detection of the genes that encode Shiga toxin

Culture on sorbitol MacConkey agar

Which nonpathogenic Mycobacterium species is isolated most often from clinical specimens and is called the “tap water bacillus”? A. Mycobacterium kansasii B. Mycobacterium gordonae C. Mycobacterium bovis D. Mycobacterium avium

Mycobacterium gordonae

An organism isolated from urine culture with significant colony count produces the following reactions. What is the presumptive identification of the organism? TSI: K/A Indole (+) H2S (+) Deaminase (+) Urease (+) Motility: swarming A. Citrobacter freundii B. Proteus vulgaris C. Pantoea agglomorens D. Proteus mirabilis E. Serratia marcescens

Proteus vulgaris

All of the following are characteristics of Helicobacter pylori except: A. Curved gram-negative bacillus B. Microaerophilic and capnophilic C. Oxidase positive D. Urease negative

Urease negative

Regan – Lowe agar is an enriched and selective medium for the isolation of : A. Bordetella pertussis B. Campylobacter jejuni C. Legionella pneumophila D. Haemophilus ducryei E. Listeria monocytogenes

Bordetella pertussis

Rickettsiae infecting man multiply preferentially within which of the following cells? A. Reticuloendothelial cells B. Hepatic cells C. Endothelial cells D. Renal tubular cells E. All of the above

Endothelial cells

The preferred specimen for laboratory diagnosis of acquired cytomegalovirus infection is: A. Blood B. Urine C. Stool D. Cutaneous vesicular fluid

Blood

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. Neisseria spp. C. Bacillus spp. D. Streptococcus spp

Lactobacillus spp.

Sputum samples for tuberculosis screening are optimally collected: A. in the morning on 3 consecutive days B. in the evening on 3 consecutive days C. 24-hour sputum collection D. Randomized sputum collection

in the morning on 3 consecutive days

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

Respiratory syncytial virus (RSV)

Fastidious, gram-negative bacilli produce colonies that pit the agar surface and produce a characteristic bleach like odor can be identified as: A. Bacteroides fragilis B. Eikenella corrodens C. Pasteurella multocida D. Listeria monocytogenes

Eikenella corrodens

The characteristics of Shigella spp. include all of the following except: A. Motile by single polar flagellum B. Non-lactose fermenter C. Oxidase negative D. Nitrate positive

Motile by single polar flagellum

Cerebrospinal fluid should be cultured immediately, but if delayed, the specimen should be: A. Refrigerated at 4-6 C B. Frozen at -20 C C. Stored at room temperature for 24 hours D. Incubated at 37 C and cultured as soon as possible

Incubated at 37 C and cultured as soon as possible