BOC MICROBIOLOGY EXAM QUESTIONS

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BOC MICROBIOLOGY EXAM QUESTIONS

Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -30 Questions and Answers

-Format: Multiple-choice / Flashcard

Question 1: Deoxycholate agar (DCA) is useful for the isolation of?

Answer:

Enterobacteriaceae Question 2: 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:

Answer:

60 seconds Question 3: Which class of antibiotics is used for the treatment of serious gram-negative infections as well as infections with Mycobacterium tuberculosis?

Answer:

Aminoglycosides Question 4: 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:

Answer:

Haemophilus influenzae and Haemophilus parainfluenzae

Question 5: Cerebrospinal fluid (CSF) should be cultured immediately, but if delayed the

specimen should be:

Answer:

Incubated at 37C and cultured as soon as possible Question 6: What is the primary and differential media of choice for recovery of most fecal pathogens?

Answer:

Hekotoen, MacConkey, Campy, colistin-nalidixic acid (CNA) agars Question 7: Semisolid transport media such as Amies, Stuart, or Cary-Blair are suitable for the

transport of swabs for culture of most pathogens except:

Answer:

Neisseria gonorrhoeae Question 8: What is the best method of recovery of anaerobic bacteria from a deep abscess?-Cotton Fiber swab of abscess area -Skin snip of surface tissue -Needle aspirate after surface decontamination -Swab of the scalpel used for debridement

Answer:

Needle aspirate after surface decontamination Question 9: What is the media of choice for recovery of Vibrio cholerae from a stool specimen?

Answer:

Thiosulfate-citrate-bile-sucrose (TCBS) agar and alkaline peptone water (APW) broth Question 10: What is the best medium suited for the recovery of Yersinia enterocolitica from a patient with gastroenteritis?

Answer:

Cefsulodin-Irgasan-NOvobiocin (CIN) agar Question 11: Would it be appropriate to transport culture speciments attempting to isolate N.gonorrhoeae from a genital specimen in ambient oxygen at 37C?

Answer:

No, cultures should be incubated in 3% to 7%CO2 at 35C.

Question 12: A flexible calcium alginate nasopharyngeal swab is the collection device of choice for recovery of which organism from the nasopharynx?

Answer:

Corynebacterium diphtheriae Question 13: Specimens for virus culture should be transported in media containing:

Answer:

Antibiotics and nutrient.Question 14: SITUATION: A group of elementary students became ill after eating undercooked ground beef prepared in the school cafeteria. The suspected pathogen,

• coli serotype O157:H7, is usually recovered using which of the following media?

Answer:

MacConkey agar with sorbitol Question 15: Chocolate agar and modified Thayer-Martin agar are used for the recovery of?

Answer:

Haemophilus spp. and N. gonorrhoeae, respectively.Question 16: In the United States, most blood agar plates are prepared with 5% or 10% red

blood cells (RBCs) obtained from:

Answer:

Sheep Question 17: Cycloserine-cefoxitin-fructose agar (CCFA) is used for the recovery of?

Answer:

Clostridium difficile Question 18: SITUATION: Abdominal pain, fever, vomiting, and nausea propted 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?

Answer:

Aeromonas hydrophilia

Question 19: What is the purpose of adding 0.025% to 0.050% sodium polyanetholsulfonate (SPS) to nutrient broth media for the collection of blood cultures?

Answer:

It inhibits phagocytosis and complement Question 20: Which procedure is appropriate for culture of genital specimens in order to recover Chlamydia spp.?

Answer:

Inoculate cycloheximide-treated McCoy cells. (Chlamydia is an intracellular species).Question 21: SITUATION: Several attendees of a medical confrence in the Gulf coast area became ill after frequenting a seafood restaurant. Apresumptive 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.

Answer:

Mannitol fermentation, Na+ requirement

Question 22: Which of the following variables may change the results of an MIC

Answer:

Inoculum size, Incubation time, growth rate of the bacteria.Question 23: Colistin-nalidixic acid agar (CNA) is used primarily for the recovery of:

Answer:

Staphylococcus aureus Question 24: The aseptic collection of blood cultures requires that the skin be cleansed with:

Answer:

70% alcohol and 2% iodine or an iodophor.Question 25: 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?

Answer:

The swarming area should be ignored