Question 1

A slow-growing, acid-fast bacillus provides the following reactions:
  Which of the following patient history/specimen types was the original source for this organism?

Accepted Answer

A)  Stool from a 44-year-old male with HIV 
B)  Sputum from an 18-year-old female illegal alien from Mexico 
C)  Skin lesion from a 39-year-old female who owns a tropical fish store 
D)  Lymph node from a 4-month-old male after receiving the BCG vaccine 
A)  Stool from a 44-year-old male with HIV 
B)  Sputum from an 18-year-old female illegal alien from Mexico 
C)  Skin lesion from a 39-year-old female who owns a tropical fish store 
D)  Lymph node from a 4-month-old male after receiving the BCG vaccine A

Question 2

The use of multiple drugs to treat tuberculosis is necessary to ensure

Accepted Answer

A)  the patient will be compliant and take at least one of the drugs. 
B)  synergy of the drugs' modes of action. 
C)  resistance does not develop. 
D)  adequate treatment. 
A)  the patient will be compliant and take at least one of the drugs. 
B)  synergy of the drugs' modes of action. 
C)  resistance does not develop. 
D)  adequate treatment. C

Question 3

All of the following statements are true concerning atypical Mycobacterium spp. except

Accepted Answer

A)  Immunocompromised individuals are at highest risk for infection. 
B)  They are spread via person-to-person contact. 
C)  They present with respiratory illness. 
D)  Transmission is via environmental sources. 
A)  Immunocompromised individuals are at highest risk for infection. 
B)  They are spread via person-to-person contact. 
C)  They present with respiratory illness. 
D)  Transmission is via environmental sources. B

Question 4

The diagnosis of Hansen's disease is made by

Accepted Answer

A)  demonstration of acid-fast bacilli in tissue. 
B)  presumptive identification based on colony morphology. 
C)  biochemical testing. 
D)  all of the above. 
E)  b and c. 
A)  demonstration of acid-fast bacilli in tissue. 
B)  presumptive identification based on colony morphology. 
C)  biochemical testing. 
D)  all of the above. 
E)  b and c.

Question 5

A sputum, submitted for AFB culture and smear, demonstrates the Kinyoun stain provided.
  Source: CDC and Dr. George P. Kubica
The organism isolated on Lowenstein-Jensen agar provided the following reactions:
Pigment: buff-colored colonies in the dark and yellow when exposed to light
  This organism is

Accepted Answer

A)  Mycobacterium gordonae. 
B)  M. marium. 
C)  M. kansasii. 
D)  M. bovis. 
A)  Mycobacterium gordonae. 
B)  M. marium. 
C)  M. kansasii. 
D)  M. bovis.

Question 6

If a slow-growing, acid-fast bacillus is able to produce an orange pigment when grown in dark or light, it is classified as Runyoun group

Accepted Answer

A)  I - photochromogen 
B)  II - Scotochromogen 
C)  III - Nonphotochromogen 
D)  IV - Rapid grower 
A)  I - photochromogen 
B)  II - Scotochromogen 
C)  III - Nonphotochromogen 
D)  IV - Rapid grower

Question 7

Mycobacterium fortuitum is classified as a

Accepted Answer

A)  photochromogen. 
B)  scotochromogen. 
C)  nonphotochromogen. 
D)  rapid grower. 
A)  photochromogen. 
B)  scotochromogen. 
C)  nonphotochromogen. 
D)  rapid grower.

Question 8

Select the correct organism/unique characteristic.

Accepted Answer

A)  Mycobacterium gordonae/cording 
B)  M. marinum/rate of growth 
C)  M. leprae/nonculturable 
D)  M. haemophilum/growth at 42°C 
A)  Mycobacterium gordonae/cording 
B)  M. marinum/rate of growth 
C)  M. leprae/nonculturable 
D)  M. haemophilum/growth at 42°C

Question 9

To differentiate the species within the Mycobacterium avium complex, one would use

Accepted Answer

A)  tellurite reduction. 
B)  pyrazinamidase. 
C)  16sRNA genotyping. 
D)  a and c. 
E)  b and c. 
A)  tellurite reduction. 
B)  pyrazinamidase. 
C)  16sRNA genotyping. 
D)  a and c. 
E)  b and c.

Question 10

Which of the following Mycobacterium spp. is considered fastidious?

Accepted Answer

A)  M. haemophilum 
B)  M. avium-intracellulare complex 
C)  M. tuberculosis 
D)  M. fortuitum complex 
A)  M. haemophilum 
B)  M. avium-intracellulare complex 
C)  M. tuberculosis 
D)  M. fortuitum complex

Question 11

Which of the following organisms morphologically resembles Mycobacterium tuberculosis but is nitrate and niacin negative?

Accepted Answer

A)  Mycobacterium fortuitum 
B)  M. bovis 
C)  M. scrofulaceum 
D)  M. kansasii 
A)  Mycobacterium fortuitum 
B)  M. bovis 
C)  M. scrofulaceum 
D)  M. kansasii

Question 12

An acid-fast bacillus is recovered from a bronchial washing on Lowenstein-Jensen medium after 18 days at 35°C with CO2. Initially the colonies are buff, raised, and rough when grown in the dark. After exposure to light, no change in pigmentation is noted. On examination at 10X magnification, the colonies reveal serpentine cording. Which of the following biochemical test reactions will confirm the identity of the most likely etiologic agent?

Accepted Answer

A)  Niacin and nitrate negative 
B)  Niacin and nitrate positive 
C)  Niacin positive and nitrate negative 
D)  Niacin negative and nitrate positive 
A)  Niacin and nitrate negative 
B)  Niacin and nitrate positive 
C)  Niacin positive and nitrate negative 
D)  Niacin negative and nitrate positive

Question 13

A skin lesion grows an acid-fast bacilli on Lowenstein-Jensen agar at 30°C but not 35°C. This organism will be a

Accepted Answer

A)  scotochromogen. 
B)  photochromogen. 
C)  nonphotochromogen. 
D)  rapid grower. 
A)  scotochromogen. 
B)  photochromogen. 
C)  nonphotochromogen. 
D)  rapid grower.

Question 14

Mycobacterium tuberculosis is classified as a

Accepted Answer

A)  photochromogen. 
B)  scotochromogen. 
C)  nonphotochromogen. 
D)  none of the above. 
A)  photochromogen. 
B)  scotochromogen. 
C)  nonphotochromogen. 
D)  none of the above.

Question 15

The presence of acid-fast bacilli in a skin lesion but the inability to grow the organism on Lowenstein-Jensen medium is characteristic for

Accepted Answer

A)  Mycobacterium fortiutum. 
B)  M. haemophilum. 
C)  M. leprae. 
D)  b and c. 
A)  Mycobacterium fortiutum. 
B)  M. haemophilum. 
C)  M. leprae. 
D)  b and c.

Question 16

Which of the following organisms is used to create the BCG vaccine?

Accepted Answer

A)  Buff colored colony that is niacin and nitrate negative 
B)  Buff colored colony that is niacin negative and nitrate positive 
C)  Buff colored colony hat is niacin and nitrate positive 
D)  Orange-pigmented colony that is nitrate negative 
A)  Buff colored colony that is niacin and nitrate negative 
B)  Buff colored colony that is niacin negative and nitrate positive 
C)  Buff colored colony hat is niacin and nitrate positive 
D)  Orange-pigmented colony that is nitrate negative

Question 17

The acid-fast colonies in the image provided demonstrated no color change with exposure to light.
  Source: CDC and Dr. George Kubica
Given that the organism produces a yellow color on the niacin accumulation test and pink color on the nitrate reduction test, what additional characteristic is considered presumptive for this organism?

Accepted Answer

A)  Serpentine cording 
B)  Rapid growth 
C)  Requirement for hemin 
D)  Growth at 30°C 
A)  Serpentine cording 
B)  Rapid growth 
C)  Requirement for hemin 
D)  Growth at 30°C

Question 18

The source for many Mycobacterium spp. is

Accepted Answer

A)  soil. 
B)  water. 
C)  animals. 
D)  all of the above. 
E)  a and b. 
A)  soil. 
B)  water. 
C)  animals. 
D)  all of the above. 
E)  a and b.

Question 19

Infections due to tubercle bacilli are

Accepted Answer

A)  typically due to exposure to the organisms in soil and water. 
B)  not seen in industrialized countries. 
C)  characterized by the formation of cheese-like necrosis and lesions. 
D)  only found in immunocompromised individuals. 
A)  typically due to exposure to the organisms in soil and water. 
B)  not seen in industrialized countries. 
C)  characterized by the formation of cheese-like necrosis and lesions. 
D)  only found in immunocompromised individuals.

Question 20

Molecular testing is a valuable tool useful in the detection of

Accepted Answer

A)  M. tuberculosis. 
B)  M. haemophilum. 
C)  M. leprae. 
D)  all of the above. 
A)  M. tuberculosis. 
B)  M. haemophilum. 
C)  M. leprae. 
D)  all of the above.

Exam 26: Mycobacterium Species

A slow-growing, acid-fast bacillus provides the following reactions: Which of the following patient history/specimen types was the original source for this organism?

The use of multiple drugs to treat tuberculosis is necessary to ensure

All of the following statements are true concerning atypical Mycobacterium spp. except

The diagnosis of Hansen's disease is made by

A sputum, submitted for AFB culture and smear, demonstrates the Kinyoun stain provided. Source: CDC and Dr. George P. Kubica The organism isolated on Lowenstein-Jensen agar provided the following reactions: Pigment: buff-colored colonies in the dark and yellow when exposed to light This organism is

If a slow-growing, acid-fast bacillus is able to produce an orange pigment when grown in dark or light, it is classified as Runyoun group

Mycobacterium fortuitum is classified as a

Select the correct organism/unique characteristic.

To differentiate the species within the Mycobacterium avium complex, one would use

Which of the following Mycobacterium spp. is considered fastidious?

Which of the following organisms morphologically resembles Mycobacterium tuberculosis but is nitrate and niacin negative?

A skin lesion grows an acid-fast bacilli on Lowenstein-Jensen agar at 30°C but not 35°C. This organism will be a

Mycobacterium tuberculosis is classified as a

The presence of acid-fast bacilli in a skin lesion but the inability to grow the organism on Lowenstein-Jensen medium is characteristic for

Which of the following organisms is used to create the BCG vaccine?

The source for many Mycobacterium spp. is

Infections due to tubercle bacilli are

Molecular testing is a valuable tool useful in the detection of

Development of Diagnostic Microbiology

Taxonomy and Classification

The Bacterial Cell

The Hosts Encounter With Microbes

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Immunological Tests

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