Mycobacteria Quiz Flashcards
(15 cards)
The best specimen for recovery of 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
a. First morning specimen
Mycobacteria stained by Ziehl-Neelsen or Kinyoun methods with methylene blue counter stain 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
a. Bright red rods against a blue background
Which of the following mycobacteria produces pigmented colonies in the dark (is a scotochromogen)?
a. M. xenopi
b. M. kansasii
c. M. tuberculosis
d. M. szulgai
d. M. szulgai
All of the following mycobacteria are associated with skin infections except:
a. M. marinum
b. M. hemophilum
c. M. kansasii
d. M. ulcerans
c. M. kansasii
Mycobacteria isolated from a respiratory culture grew best at 42C. Colonies on LJ medium were not pigmented after exposure to light and negative for niacin accumulation and nitrate reduction. The most likely identification is:
a. M. marinum
b. M. ulcerans
c. M. xenopi
d. M. hemophilum
c. M. xenopi
Which of the following mycobacteria is best differentiated by the rapid (w/in 6 hours) hydrolysis of tween 80 ?
a. M. fortuitum
b. M. chelonae
c. M. kansasii
d. M. gordonae
c. M. kansasii
An employee of a tropical fish store had a skin infection a finger. The lesion was cultured and grew an acid fast bacilli. The organism grew best at 30C. was nonpigmented when grown in the dark and produced a deep yellow color when exposed to light.
This organism is most likely:
a. M. tuberculosis
b. M. marinum
c. M. xenopi
d. M. ulcerans
b. M. marinum
A Mycobacterium species is recovered from a patient with AIDS gave the following results:
Niacin = NEG
Tween 80 hydrolysis = NEG
Nitrate reduction = NEG
Heat stable catalase (68C) = +/-
Non-photochromogen
What is the most likely identification?
a. M. gordonae
b. M. bovis
c. M. avium complex
d. M. kansasii
c. M. avium complex
Which nonpathogenic Mycobacterium sp. is isolated most often from clinical specimens and is called the ‘tapwater bacillus’?
a. M. kansasii
b. M. avium complex
c. M. leprae
d. M. gordonae
d. M. gordonae
Rapid methods for identifying infection with M. tuberculosis include:
a. HPLC
b. Nucleic acid probes
c. Acid-fast smears
d. All of the above
d. All of the above
A bile-tolerant, gram-negative anaerobic bacillus indicates that the isolate is likely a member of the ___________ group.
a. Actinomyces
b. Porphyromonas and Prevotella
c. Bacteroides fragilis
d. Clostridium difficile
c. Bacteroides fragilis
An anaerobic GPB that demonstrates double-zone hemolysis on anaerobic blood agar:
a. Bacteroides fragilis
b. Actinomyces
c. Clostridium difficile
d. Clostridium perfringens
d. Clostridium perfringens
Actinomyces israelii is an opportunistic pathogen with infections primarily seen in:
a. Skin infections
b. Oral infections
c. Ear infections
d. None of the above
b. Oral infections
Lab diagnosis of C. difficile infection:
a. Involves testing for Antigen & Toxin
b. Should only be done on unformed stool specimens
c. Should only be done by culture methods
d. A & B are correct
d. A & B are correct
A positive blood culture grows a small anaerobic club-shaped gpb that is:
Catalase positive
Indole positive
What is the most likely identification?
a. Bacillus species
b. Clostridium perfringens
c. Actinomyces
d. Propionibacterium acnes
d. Propionibacterium acnes
