問題一覧
1
The best specimen for recovery of the mycobacteria from a sputum sample is?
First morning specimen
2
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
3
Which is the most appropriate nonselective medium for recovery of mycobacteria from a heavily contaminated specimen?
Petragnani's agar
4
Mycobacteria stained by the Ziehl-Neelsen or Kinyoun methods with methylene blue counterstain are seen microscopically as:
Bright red rods against a blue background
5
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
6
Which organism, associated with tubercolosis in cattle, causes tubercolosis in humans, especially in regions where dairy farming is prevalent?
Mycobacterium bovis
7
Which of the following organisms are used as controls for rapid growers and slow growers?
Mycobacterium fortuitum and Mycobacterium tuberculosis
8
Which of the following Mycobacterium spp. produce(s) pigmented colonies in the dark (is a scotochromogen)?
M. szulgai
9
All of the following mycobacteria are associated with skin infections except:
Mycobacterium kansasii
10
All of the following Mycobacterium spp. produce the enzyme required to convert niacin to niacin ribonucleotide except:
M. tuberculosis
11
The catalase test for mycobacteria differs from that used for other types of bacteria by using:
30% H2O2 and 10% Tween 80
12
Growth inhibition by thiophene-2-carboxylic hydrazide (T2H) is used to differentiate M. tubercolosis from which other Mycobacterium spp.?
M. bovis
13
Which of the following Mycobacterium spp. is best differentiated by the rapid hydrolysis of Tween 80?
M. kansasii
14
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
15
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
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
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
19
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
20
Which nonpathogenic Mycobacterium spp. is isolated most often from clinical specimens and is called the "tapwater bacillus"?
M. gordonae
21
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
22
How long should Mycobacterium tubercolosis-positive cultures be kept by the laboratory after identification and antibiotic susceptibility testing have been performed?
6-12 months
23
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+
24
Which of the following Mycobacterium spp. would be most likely to grow on a MacConkey agar plate?
M. chelonae-fortuitum complex
25
Rapid methods for identifying classic infection with M. tubercolosis include:
All of these options
26
Individuals showing a positive purified protein derivative (PPD) skin test for M. tubercolosis are usually:
Latently infected
27
Which of the following Mycobacterium spp. is diagnosed by means other than culture?
M. leprae
28
Which M. avium complex (MAC) organism is the most frequently isolated mycobacterium from AIDS patients?
M. avium
29
Which mycobacterium of the M. tubercolosis complex fails to grow in culture and has a characteristic "croissant-like" morphology in stained smears?
M. microti
30
Which two mycobacteria commonly isolated from subcutaneous skin have an optimal growth temperature of 30°C?
M. haeophilum and M. ulcerans
31
Which mycobacterium is associated with Crohn's disease?
M. paratuberculosis
32
Which temperature range is ideal for the recovery of M. marinum?
30°C - 32°C