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8. The supervisor wants you to predict what growth will occur and on what plates, based on what you see microscopically in the gram stain from a fecal sample.

http://homepage.usask (9.19.09)

a. What organism do you think it is?

b. What media will it grow on and how do you incubate it?

9. One of the enterotoxins produced by enterotoxigenic Eschericha coli in travelerâs diarrhea is similar to a toxin produced by __________________________.

a. How does this toxin work?

10. You have narrowed the id of an organism from a fecal sample down to either Salmonella or Citrobacter.

a. What media would you use to differentiate the two organisms

b. Describe the growth on the media for each organism.

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5. Some bacteria live in deep sea vents where no light penetrates, yet are still capable of producing their own reduced carbon (e.g. fixing carbon dioxide). These organisms are classified as

(A) photoheterotroph (B) photoautotroph

(C)chemoheterotroph (D)chemoautotroph

(E) organotroph

6. Nitrogen fixation is the conversion of

(A) ammonium ion to nitrogen gas. (B) nitrogen gas to ammonium ion.

(C)nitrate ion to nitrogen gas. (D)ammonium ion to nitrate ion.

(E) nitrate ion to ammonium ion.

7. Which of the following is true of complex media?

(A) Bacteria grow faster on them than on synthetic media.

(B) All the chemical components and their concentrations are known.

(C)Complex media are the most difficult of all to prepare.

(D)Complex media can help determine the metabolic capacity of an organism.

(E) They are also called minimal media.

8. Which of the following types of growth media contains blood?

(A) minimal media (B) complex media

(C)defined media (D)enriched media

(E) selective media

9. The bile salts and crystal violet in MacConkey lactose plates prevent the growth of Gram-positives. These additives make the MacConkey plate a

(A) complex medium. (B) defined medium.

(C)minimal medium. (D)selective medium.

(E) differential medium.

10. You discover a new bacterial efflux pump that moves an uncharged toxin out of the cell using the proton motive force as the energy source. This new transporter can be classified as an

(A) electrogenic antiporter (B) electrogenic symporter

(C)electroneutral antiporter (D)electroneutral symporter

(E) none of the above

11. Which of the following involves nitrate as a terminal electron acceptor?

(A) photosynthesis (B) aerobic respiration

(C)fermentation (D)anaerobic respiration

(E) glycolysis

12. Which of the following is least likely to use glucose (an organic molecule) as a source of electrons?

(A) lithotrophy (B) organotrophy

(C)aerobic respiration (D)anaerobic respiration

(E) heterotrophy

17. Which of the following nutrient uptake systems does not require cellular energy?

(A) facilitated diffusion (B) coupled transport

(C)ABC transporters (D)group translocation

(E) All of the above require energy expenditure by the cell

18. What is the energy source for ABC transporters?

(A) proton motive force (B) NADH

(C)phosphoenolpyruvate (PEP) (D)ATP

(E) No energy is required for ABC transport.

19. Which of the following is true of all biofilms?

(A) They only contain a single species of bacteria.

(B) Biofilms can form on a range of biotic or abiotic surfaces.

(C)Cells in a biofilm are dormant until the bacteria leave the biofilm.

(D)Biofilms are composed of a single monolayer of EPS.

(E) Biofilms are not found in or on the human body.

20. The heterocyst cells of cyanobacteria are specialized for

(A) photosynthesis (B) gliding motility

(C)nitrogen fixation (D)carbon fixation

(E) antibiotic production

1. An organism, observed on direct Gram stain from a clinical specimen, does not grow on blood or chocolate agars incubated at 35Â°C in CO₂. This can be explained by all of following statements except

a. the organism is an anaerobe.

b. the organism is dead due to previous antibiotic therapy.

c. the organism requires nicotinamide adenine dinucleotide for growth.

d. the organism is fastidious and is not being provided the growth factor it needs.

2. The laboratory should be notified in advance when the physician suspects Francisella tularensis because the organism is

a. fastidious and requires special medium.

b. infectious for laboratory personnel.

c. not culturable.

d. a and b.

e. b and c.

3. The HACEK organisms share all of the following characteristics except

a. gram-negative coccobacilli that are oxidase and catalase positive.

b. slow growing and stimulated by carbon dioxide.

c. part of the normal oral flora.

d. causative agents of bacterial endocarditis.

4. Legionella pneumophila and Francisella tularensis share the characteristic of

a. being easily identified by biochemical testing.

b. a requirement for cysteine to grow in culture.

c. the necessity for the use of Gimenez stain rather than Gram stain to visualize.

d. having an animal reservoir.

5. Legionella pneumophila and Francisella tularensis share all of the following characteristics except

a. poor Gram staining properties.

b. ability to cause pneumonia.

c. ability to diagnose infection with detection of serum antibodies.

d. fluorescence of colonies.

6. A blood culture isolate that stains as pleomorphic gram-negative coccobacillus and only grows on chocolate agar should be

a. identified using the ALA test.

b. identified using the ALA and horse blood agar tests.

c. presumptively identified under BSL 2 conditions.

d. identified using X and V factor disks and horse blood agar.

7. Which of the following organisms requires factor X only on initial isolation but loses the requirement on subculture?

a. Aggregatibacter actinomycetemcomitans

b. Eikenella corrodens

c. Francisella tularensis

d. Aggregatibacter aphrophilus

8. Haemophilus ducreyi is unique among the genus because it requires

a. factors X and V.

b. no factors.

c. heme only.

d. NAD only.

9. Streptobacillus moniliformis is most easily isolated from blood cultures because it requires _____ for growth.

a. heme

b. serum

c. cysteine

d. 1% Î±-ketoglutarate

10. A 57-year-old male farmer sees his physician complaining of fever, night sweats, and lethargy that come and go over the past three months. The patientâs history reveals that he raises sheep for wool and meat and goats for milk. The physician suspects undulant fever. What is the optimal specimen(s) for culture of this suspected organism?

a. Blood

b. Bone marrow

c. Lymph node biopsy

d. All of the above

e. B and C

11. A microbiologist processes a specimen for culture using a buffered charcoal yeast extract agar plate. What was the original specimen used for inoculation of this agar plate?

a. Blood

b. Lower respiratory specimen

c. Nasopharyngeal

d. Urine

12. A nasopharyngeal swab containing ciliated epithelial cells is the best specimen for the recovery of the organism that causes

a. whooping cough.

b. undulant fever.

c. rat bite fever.

d. legionnaireâs disease.

13. What is the clinical significance of ALA-positive, gram-negative coccobacilli in a sputum culture?

Normal flora

Potential pathogen

Significant if it is hemolytic on horse blood agar

Further testing is needed to assess significance

14. A small, slender, gram-negative rod was recovered from the blood cultures of a patient following root canal surgery. At 48 hours, the following results were observed:

BAP and CHOC agars: small gray colonies that tend to pit the agar

MAC agar: no growth

Odor upon opening the agar plates: bleach-like

This organism will also be

a. catalase and oxidase positive.

b. catalase positive and oxidase negative.

c. catalase and oxidase negative.

d. catalase negative and oxidase positive.

15. A pleomorphic gram-negative coccobacillus is isolated from the blood cultures of 58-year-old male who had recent dental surgery. His history is significant for rheumatic fever as a child. The organism only grows on chocolate agar. It should be tested using

a. ALA.

b. X and V factor disks.

c. ALA and horse blood agar.

d. X and V factors and horse blood agar.

16. The virulence of Bordetella pertussis is related to its

a. toxinâs ability to paralyze ciliated epithelial cells.

b. ability to hide in the reticuloendothelial system.

c. easy dissemination.

d. ability to live inside white blood cells.

17. Infection due to Brucella spp. is often slow to develop, long term, and displaying periodicity. This can be explained by the organismâs ability to

a. colonize the upper respiratory tract prior to infection.

b. travel and hide in the reticuloendothelial system.

c. cause infection as the vaccine wanes in adults.

d. change its surface antigens.

18. A 10-year-old male gave mouth-to-mouth resuscitation to his pet guinea pig, which proceeded to bite him on the lip. The guinea pig did not survive. Two days after the guinea pigâs funeral, the boy became ill with fever, chills, joint pain, and a rash. What organism should the physician suspect based on the patientâs history?

a. Brucella spp.

b. Francisella tularensis

c. Streptobacillus moniliformis

d. Eikenella corrodens

19. You and your best friend get into a fist fight. Your knuckles are torn and bleeding afterwards. What organism are you likely to isolate if your wounds become infected?

a. Kingella kingae

b. Eikenella corrdens

c. Aggregatibacter aphrophilus

d. Cardiobacterium hominis

20. Epiglottitis, a severe life-threatening infection occurring in non-vaccinated infants and children, is most commonly caused by

a. a pleomorphic gram-negative coccobacillus that is ALA positive and horse blood agar positive.

b. a gram-negative coccobacillus that is identified by direct fluorescent antibody and slide agglutination tests.

c. a gram-negative coccobacillus that is best identified by a rise in antibody titer in serum samples drawn two weeks apart.

d. a pleomorphic gram-negative coccobacillus that requires X and V factors and is horse blood agar negative.

21. An organism isolated from the swab of purulent eye drainage shows no fluorescence on the ALA test. The horse blood agar displays no hemolysis. This organism should be reported as

a. Haemophilus influenzae.

b. H. aegyptius.

c. H. influenzae or H. aegyptius, biochemically similar.

d. H. parainfluenzae.

22. Because of the nature of the profession, a veterinarian is at increased risk of acquiring

1. Brucella spp.

2. Aggregatibacter actinomycetemcomitans

3. Francisella tularensis

4. Streptobacillus moniliformis

5. Eikenella corrodens

a. 1, 2, 4, and 5

b. 1, 3, and 4

c. 2, 3, and

d. 3 and 4

yellowleopard828

2. A physician suspects her patient has erysipeloid. She calls the laboratory for help with specimen selection and collection. You recommend she collect a

a. swab of infected skin surface.

b. nasopharyngeal swab.

c. swab of sinus tract drainage.

d. full thickness biopsy.

ANSWER:

(Level 1, Objective 2)

4. Loefflerâs medium is useful in making a presumptive identification of Corynebacterium diphtheriae from a pharyngeal culture because it

a. inhibits the growth of normal upper respiratory flora.

b. detects hydrogen sulfide production.

c. enhances metachromatic granule formation.

d. detects toxin-producing strains.

ANSWER:

(Level 1, Objective 3)

5. Overlaying an agar plate with sterile olive oil ensures adequate growth of

a. Erysipelothrix rhusiopathiae.

b. Arcanobacterium haemolyticum.

c. Lactobacillus spp.

d. Corynebacterium urealyticum.

ANSWER:

(Level 1, Objective 3)

6. The breakdown of casein, tyrosine, and xanthine is used in differentiating ____________ spp.

a. Nocardia

b. Streptomyces

c. Actinomyces

d. Corynebacterium

ANSWER:

(Level 1, Objective 4)

7. A positive reaction for the inverse CAMP test appears as an arrowhead of

a. non-hemolysis for Arcanobacterium haemolyticum when tested against Group B Streptococcus.

b. non-hemolysis for Corynebacterium ulcerans when tested against Staphylococcus aureus.

c. enhanced hemolysis for Arcanobacterium haemolyticum when tested against Group B Streptococcus.

d. enhanced hemolysis for Corynebacterium ulcerans when tested against Staphylococcus aureus.

ANSWER:

(Level 2, Objective 4)

8. Nocardia, Actinomyces, and Streptomyces spp. microscopically appear as

a. palisading, clubbed, gram-positive rods.

b. gram-variable rods.

c. branching gram-positive rods.

d. long, thin, gram-positive rods.

ANSWER:

(Level 1, Objective 5)

9. Lactobacillus spp. typically produce colonies that are

a. white and chalky.

b. large, dry, and beta-hemolytic.

c. gray-white, translucent. with subtle beta-hemolysis.

d. pinpoint and alpha-hemolytic.

ANSWER:

(Level 1, Objective 5)

10. Which of the following tests can be used to identify Gardnerella?

1. Catalase negative

2. Oxidase positive

3. Beta hemolysis on human blood agar

4. Beta hemolysis on sheep blood agar

5. Starch fermentation

a. 1, 2, 3, and 5

b. 2, 4, and 5

c. 1 and 3

d. 1, 3, and 5

ANSWER:

(Level 2, Objectives 5 and 6)

11. The only catalase-negative, gram-positive rod capable of producing hydrogen sulfide is also

a. intrinsically vancomycin resistant.

b. esculin positive.

c. motile.

d. gelatinase positive.

ANSWER:

(Level 2, Objectives 5 and 6)

12. A pinpoint, gray-white colony is isolated as >100,000 colonies/mL from the urine of an 89-year-old leukemic patient. The colony stains as palisading gram-positive rods. The organism should be

a. catalase negative and urea positive.

b. catalase positive and urea positive.

c. catalase negative and urea negative.

d. catalase positive and urea negative.

ANSWER:

(Level 2, Objective 6)

13. The gram-positive rod that produces an umbrella motility pattern in semisolid medium is also

a. catalase positive.

b. esculin negative.

c. non-hemolytic.

d. sodium hippurate negative.

ANSWER:

(Level 2, Objective 6)

14. The colonies of Streptococcus agalactiae and Listeria monocytogenes are nearly identical. The two organisms can be differentiated by the

a. sodium hippurate hydrolysis test.

b. CAMP factor test.

c. catalase test.

d. diseases they cause.

ANSWER:

(Level 1, Objective 7)

15. A 20-year-old female presents with pharyngitis. The rapid group A Streptococcus screen is negative, and a blood agar plate is inoculated. After 24 hours incubation, a tiny gray colony with a narrow zone of beta-hemolysis is observed. The microbiologist performs a streptococcal serotype for group A and the result is negative. She should

a. perform a Gram stain and catalase test.

b. finalize the culture as âNo Group A Streptococcus isolated.â

c. repeat the streptococcal serotype after boiling the organism suspension.

d. perform an ELEK test.

ANSWER:

(Level 2, Objective 7)

17. Which of the following organisms is not considered pathogenic until it has been infected by a bacteriophage?

a. Bacillus anthracis

b. Corynebacterium pseudotuberculosis

c. C. diphtheriae

d. Actinomyces israelii

ANSWER:

(Level 1, Objective 9)

19. The modified ELEK test is used to

a. detect the metachromatic granules of Corynebacterium diphtheriae.

b. identify C. diphtheriae.

c. detect toxin-producing strains of C. diphtheriae.

d. differentiate C. jeikeium and C. urealyticum.

ANSWER:

(Level 1, Objective 9)

20. A leg wound from a 15-year-old male football player yields:

Heavy growth of Staphylococcus aureus

Light growth of Staphylococcus not S. aureus

Light growth of Diphtheroids

Light growth of viridians Streptococcus

The microbiologist should

a. report the Staphylococcus aureus and call the other organisms normal skin flora.

b. report each of the organisms isolated individually.

c. perform further testing on the diphtheroids.

d. report all four organisms as normal skin flora.

ANSWER:

(Level 2, Objective 10)

21. Individuals infected with toxigenic Corynebacterium diphtheriae must be treated with

a. penicillin.

b. DPT vaccine.

c. antitoxin.

d. a and c.

e. b and c.

ANSWER:

(Level 1, Objective 11)

22 A gray-white colony displaying subtle beta-hemolysis is isolated from a cerebrospinal fluid. The organism is a gram-positive rod that is catalase positive, motile at room temperature, and esculin positive. Which patient history is most likely associated with this culture?

a. 45-year-old female weaver

b. 2-day-old infant male delivered at 32 weeks gestation

c. 33-year-old female with recent dental surgery

d. 58-year-old cattle farmer

ANSWER:

(Level 2, Objective 12)