問題一覧
1
Which organism, associated with tubercolosis in cattle, causes tubercolosis in humans, especially in regions where dairy farming is prevalent?
Mycobacterium bovis
2
A Mycobacterium spp. recovered from a patient with AIDS gave the following results: Niacin: Neg Tween 80 hydrolysis = Neg Heal-stable catalase (68°C) = +,- T2H = + Nitrate reduction = Neg Nonphotochromogen
M. avium-intracellulare complex
3
Which nonpathogenic Mycobacterium spp. is isolated most often from clinical specimens and is called the "tapwater bacillus"?
M. gordonae
4
How long should Mycobacterium tubercolosis-positive cultures be kept by the laboratory after identification and antibiotic susceptibility testing have been performed?
6-12 months
5
According to the reporting standards of the American Thoracic Society, one or more acid-fast bacilli (AFB) per oil immersion field (1000x) are reported as:
Numerous or 3+
6
Which temperature range is ideal for the recovery of M. marinum?
30°C - 32°C
7
Rapid methods for identifying classic infection with M. tubercolosis include:
All of these options
8
Which of the following organisms are used as controls for rapid growers and slow growers?
Mycobacterium fortuitum and Mycobacterium tuberculosis
9
Mycobacteria isolated from the hot water system of a hospital grew at 42 degrees celsius. Colonies on Lowenstein-Jensen medium were not pigmented after exposure to light and were negative for niacin accumulation and nitrate reduction. The most likely identification is:
Mycobacterium xenopi
10
Which is the most appropriate nonselective medium for recovery of mycobacteria from a heavily contaminated specimen?
Petragnani's agar
11
Acid-fast staining of a smear prepared from digested sputum showed slender, slightly curved, beaded, red mycobacterial rods. Growth on Middlebrook 7H10 slants produced buff-colored microcolonies with a serpentine pattern after 14 days at 37 degrees celsius. Niacin and nitrate reduction test were positive. What is the most probable presumptive identification?
Mycobacterium tubercolosis
12
All of the following mycobacteria are associated with skin infections except:
Mycobacterium kansasii
13
Mycobacteria stained by the Ziehl-Neelsen or Kinyoun methods with methylene blue counterstain are seen microscopically as:
Bright red rods against a blue background
14
Individuals showing a positive purified protein derivative (PPD) skin test for M. tubercolosis are usually:
Latently infected
15
Growth inhibition by thiophene-2-carboxylic hydrazide (T2H) is used to differentiate M. tubercolosis from which other Mycobacterium spp.?
M. bovis
16
The urease test is needed to differentiate Mycobacterium scrofulaceum from which of the following mycobacteria?
M. gordonae
17
A laboratory provides the following services for identification of mycobacteria: Acid-fast staining of clinical specimens Inoculation of cultures Shipment of positive cultures to a reference laboratory for identification According to the American Thoracic Society's definition for levels of service this laboratory is:
Level I
18
The best specimen for recovery of the mycobacteria from a sputum sample is?
First morning specimen
19
Which mycobacterium is associated with Crohn's disease?
M. paratuberculosis
20
Culture of a skin (hand) wound from a manager of a tropical fish store grew on Lowenstein-Jensen agar slants at 30°C in 20 days. Given the following results, what is the most likely identification? Photochromogen = + Heat-stable catalase (68°C) = Neg Nitrate reduction = Neg Niacin = Neg Urease = + Tween 80 hydrolysis = +
Mycobacterium marinum
21
Which of the following Mycobacterium spp. produce(s) pigmented colonies in the dark (is a scotochromogen)?
M. szulgai
22
Which of the following Mycobacterium spp. would be most likely to grow on a MacConkey agar plate?
M. chelonae-fortuitum complex
23
All of the following Mycobacterium spp. produce the enzyme required to convert niacin to niacin ribonucleotide except:
M. tuberculosis
24
Which of the following Mycobacterium spp. is best differentiated by the rapid hydrolysis of Tween 80?
M. kansasii
25
What concentration of sodium hydroxide (NaOH) is used to prepare a working decontamination solution for the processing of not normally sterile specimens for mycobacteria?
4% NaoH
26
Which of the following Mycobacterium spp. is diagnosed by means other than culture?
M. leprae
27
Which M. avium complex (MAC) organism is the most frequently isolated mycobacterium from AIDS patients?
M. avium
28
Which mycobacterium of the M. tubercolosis complex fails to grow in culture and has a characteristic "croissant-like" morphology in stained smears?
M. microti
29
Which two mycobacteria commonly isolated from subcutaneous skin have an optimal growth temperature of 30°C?
M. haeophilum and M. ulcerans
30
According to the College of American Pathologists (CAP) guidelines, which services for mycobacteria would be performed by a Level II laboratory?
Acid-fast staining, inoculation, and referral to a reference laboratory
31
The catalase test for mycobacteria differs from that used for other types of bacteria by using:
30% H2O2 and 10% Tween 80
32
Which of the following drugs are first-line antibiotics used to treat classic tubercolosis for which susceptibility testing is performed by the disk diffusion method on Middlebrook 7H10 or 7H11 agar plates?
Isonicotinic acid hydrazide (INH), rifampin, ethambutol, and pyrazinamide