Question 1

Which of the following species of Mycobacterium causes a chronic disease of the skin, mucous membranes, and nerve tissue but has not yet been cultivated in vitro?

Accepted Answer

A)  M. paratuberculosis 
B)  M. lepraemurium 
C)  M. phlei 
D)  M. leprae 
A)  M. paratuberculosis 
B)  M. lepraemurium 
C)  M. phlei 
D)  M. leprae

Question 2

For reliable results, the niacin test should be performed only from cultures that are at least:

Accepted Answer

A)  2 weeks old and show at least five colonies on Löwenstein-Jensen medium. 
B)  3 weeks old and show at least 50 colonies on Löwenstein-Jensen medium. 
C)  3 weeks old and show at least 50 colonies on Middlebrook 7H11 agar. 
D)  2 weeks old and show at least five colonies on Middlebrook 7H11 agar. 
A)  2 weeks old and show at least five colonies on Löwenstein-Jensen medium. 
B)  3 weeks old and show at least 50 colonies on Löwenstein-Jensen medium. 
C)  3 weeks old and show at least 50 colonies on Middlebrook 7H11 agar. 
D)  2 weeks old and show at least five colonies on Middlebrook 7H11 agar.

Question 3

In the identification of mycobacterial isolates, the niacin test involves the:

Accepted Answer

A)  accumulation of niacin in the medium in which the organism is growing. 
B)  metabolism of niacin to nicotinic acid by enzymatic action. 
C)  testing of the isolate for susceptibility to niacin. 
D)  utilization of niacin in metabolic pathways to produce nicotinic acid. 
A)  accumulation of niacin in the medium in which the organism is growing. 
B)  metabolism of niacin to nicotinic acid by enzymatic action. 
C)  testing of the isolate for susceptibility to niacin. 
D)  utilization of niacin in metabolic pathways to produce nicotinic acid.

Question 4

Specimens for Mycobacterium studies that require concentration, decontamination, or liquefaction include:

Accepted Answer

A)  CSF and other body fluids. 
B)  sputum. 
C)  urine. 
D)  swabs and wound aspirates. 
A)  CSF and other body fluids. 
B)  sputum. 
C)  urine. 
D)  swabs and wound aspirates.

Question 5

Known to cause an inflammatory bowel disease referred to as Johne disease in cattle, sheep, and goats, which organism has been isolated from the bowel mucosa of patients with Crohn disease?

Accepted Answer

A)  M. paratuberculosis 
B)  M. avium-intracellulare 
C)  M. phlei 
D)  M. lepraemurium 
A)  M. paratuberculosis 
B)  M. avium-intracellulare 
C)  M. phlei 
D)  M. lepraemurium

Question 6

The Runyon system of classification is based on:

Accepted Answer

A)  colonial and microscopic morphologic characteristics. 
B)  biochemical characteristics. 
C)  growth rate and colonial pigmentation. 
D)  genotypic characteristics. 
A)  colonial and microscopic morphologic characteristics. 
B)  biochemical characteristics. 
C)  growth rate and colonial pigmentation. 
D)  genotypic characteristics.

Question 7

On Gram stain, mycobacteria appear as:

Accepted Answer

A)  slender, well-stained gram-positive bacilli. 
B)  poorly stained, beaded, gram-positive bacilli. 
C)  gam-variable to gram-positive bacilli. 
D)  partially invisible gram-negative bacilli. 
A)  slender, well-stained gram-positive bacilli. 
B)  poorly stained, beaded, gram-positive bacilli. 
C)  gam-variable to gram-positive bacilli. 
D)  partially invisible gram-negative bacilli.

Question 8

The primary reservoir of the Mycobacterium responsible for leprosy is:

Accepted Answer

A)  infected humans. 
B)  infected animals. 
C)  contaminated food. 
D)  contaminated objects. 
A)  infected humans. 
B)  infected animals. 
C)  contaminated food. 
D)  contaminated objects.

Question 9

Examples of the mycobacterial species that occur in humans and belong to the Mycobacterium tuberculosis complex include:

Accepted Answer

A)  M. tuberculosis, nontuberculous mycobacteria, M. bovis, and M. africanum. 
B)  M. tuberculosis, M. gordonae, M. bovis BCG, and M. africanum. 
C)  M. tuberculosis, M. bovis, M. avium, and M. intracellulare. 
D)  M. tuberculosis, M. bovis, M. bovis BCG, and M. africanum. 
A)  M. tuberculosis, nontuberculous mycobacteria, M. bovis, and M. africanum. 
B)  M. tuberculosis, M. gordonae, M. bovis BCG, and M. africanum. 
C)  M. tuberculosis, M. bovis, M. avium, and M. intracellulare. 
D)  M. tuberculosis, M. bovis, M. bovis BCG, and M. africanum.

Question 10

The nonpathogenic Mycobacterium commonly found in tap water, which has been a problem when tap water or deionized water has been used in the preparation of smears, is:

Accepted Answer

A)  M. paratuberculosis. 
B)  M. lepraemurium. 
C)  M. phlei. 
D)  M. gordonae. 
A)  M. paratuberculosis. 
B)  M. lepraemurium. 
C)  M. phlei. 
D)  M. gordonae.

Question 11

One drawback associated with the fluorochrome stain method for detecting Mycobacterium is that:

Accepted Answer

A)  it is less sensitive than the conventional carbolfuchsin stains. 
B)  it requires the smear to be initially examined at lower magnifications. 
C)  many rapid growers may not appear fluorescent with these reagents. 
D)  it increases the amount of time needed for examining smears. 
A)  it is less sensitive than the conventional carbolfuchsin stains. 
B)  it requires the smear to be initially examined at lower magnifications. 
C)  many rapid growers may not appear fluorescent with these reagents. 
D)  it increases the amount of time needed for examining smears.

Question 12

What quantity of cerebrospinal fluid (CSF)is considered sufficient for the detection of tuberculous meningitis?

Accepted Answer

A)  1 mL 
B)  5 mL 
C)  10 mL 
D)  20 mL 
A)  1 mL 
B)  5 mL 
C)  10 mL 
D)  20 mL

Question 13

A fisherman who cut himself on a fishing hook later develops a cutaneous disease at the inoculation site.The exudate is aspirated and set up on a routine AFB medium for culture.It is incubated at 37° C, but no growth is observed after 8 weeks; however, a slide of the exudate was AFB-positive.Which one of the following statements explains these findings?

Accepted Answer

A)  The infection is most likely the result of a viral infection. 
B)  The organism should have been incubated at 30° C. 
C)  The organism should have been incubated at 42° C. 
D)  The infection is most likely fungal in nature. 
A)  The infection is most likely the result of a viral infection. 
B)  The organism should have been incubated at 30° C. 
C)  The organism should have been incubated at 42° C. 
D)  The infection is most likely fungal in nature.

Question 14

The type of specimen collected for mycobacterial studies that must be neutralized with 10% sodium carbonate is:

Accepted Answer

A)  spontaneously produced sputum. 
B)  gastric lavage. 
C)  transtracheal aspiration. 
D)  bronchial lavage. 
A)  spontaneously produced sputum. 
B)  gastric lavage. 
C)  transtracheal aspiration. 
D)  bronchial lavage.

Question 15

Slow-growing NTM whose colonies produce no pigment, whether they are grown in the dark or the light, are referred to as:

Accepted Answer

A)  scotochromogens. 
B)  photochromogens. 
C)  nonphotochromogens. 
D)  chromogenicums. 
A)  scotochromogens. 
B)  photochromogens. 
C)  nonphotochromogens. 
D)  chromogenicums.

Question 16

Quality control is performed to test the validity of catalase production at 68° C.M.fortuitum and M.tuberculosis are used, which yield a positive and negative reaction, respectively.Which one of the following statements explains this discrepancy?

Accepted Answer

A)  Both organisms were most likely incubated at the wrong temperature. 
B)  Both organisms were most likely incubated on the wrong media before testing. 
C)  The catalase reagent is most likely expired. 
D)  No discrepancy is present. M. fortuitum is catalase-positive and M. tuberculosis is catalase-negative at 68° C. 
A)  Both organisms were most likely incubated at the wrong temperature. 
B)  Both organisms were most likely incubated on the wrong media before testing. 
C)  The catalase reagent is most likely expired. 
D)  No discrepancy is present. M. fortuitum is catalase-positive and M. tuberculosis is catalase-negative at 68° C.

Question 17

The specimens of choice for detecting urinary tract mycobacterial disease are:

Accepted Answer

A)  single clean-catch midstream urine samples. 
B)  24-hour timed urine samples. 
C)  three daily clean-catch midstream urine samples. 
D)  biopsies of the suspected site. 
A)  single clean-catch midstream urine samples. 
B)  24-hour timed urine samples. 
C)  three daily clean-catch midstream urine samples. 
D)  biopsies of the suspected site.

Question 18

Acid-fast smears should be examined carefully by scanning at least ________ oil immersion fields.

Accepted Answer

A)  100 
B)  200 
C)  300 
D)  400 
A)  100 
B)  200 
C)  300 
D)  400

Question 19

Mycobacterium fortuitum, M.chelonae, and M.abscessus are:

Accepted Answer

A)  responsible for approximately 90% of clinical mycobacterial disease. 
B)  unable to grow on routine bacteriologic media. 
C)  gram-negative rods resembling Escherichia coli on Gram stain. 
D)  slow growers requiring a minimum of 14 days to grow. 
A)  responsible for approximately 90% of clinical mycobacterial disease. 
B)  unable to grow on routine bacteriologic media. 
C)  gram-negative rods resembling Escherichia coli on Gram stain. 
D)  slow growers requiring a minimum of 14 days to grow.

Question 20

The stain that does not require heating the slide for better penetration of stain into the mycobacterial cell wall is known as the:

Accepted Answer

A)  Kinyoun. 
B)  Ziehl-Neelsen. 
C)  immunofluorochrome. 
D)  carbolfuchsin. 
A)  Kinyoun. 
B)  Ziehl-Neelsen. 
C)  immunofluorochrome. 
D)  carbolfuchsin.

Exam 42: Mycobacteria

Which of the following species of Mycobacterium causes a chronic disease of the skin, mucous membranes, and nerve tissue but has not yet been cultivated in vitro?

For reliable results, the niacin test should be performed only from cultures that are at least:

In the identification of mycobacterial isolates, the niacin test involves the:

Specimens for Mycobacterium studies that require concentration, decontamination, or liquefaction include:

Known to cause an inflammatory bowel disease referred to as Johne disease in cattle, sheep, and goats, which organism has been isolated from the bowel mucosa of patients with Crohn disease?

The Runyon system of classification is based on:

On Gram stain, mycobacteria appear as:

The primary reservoir of the Mycobacterium responsible for leprosy is:

Examples of the mycobacterial species that occur in humans and belong to the Mycobacterium tuberculosis complex include:

The nonpathogenic Mycobacterium commonly found in tap water, which has been a problem when tap water or deionized water has been used in the preparation of smears, is:

One drawback associated with the fluorochrome stain method for detecting Mycobacterium is that:

What quantity of cerebrospinal fluid (CSF)is considered sufficient for the detection of tuberculous meningitis?

The type of specimen collected for mycobacterial studies that must be neutralized with 10% sodium carbonate is:

Slow-growing NTM whose colonies produce no pigment, whether they are grown in the dark or the light, are referred to as:

Quality control is performed to test the validity of catalase production at 68° C.M.fortuitum and M.tuberculosis are used, which yield a positive and negative reaction, respectively.Which one of the following statements explains this discrepancy?

The specimens of choice for detecting urinary tract mycobacterial disease are:

Acid-fast smears should be examined carefully by scanning at least ________ oil immersion fields.

Mycobacterium fortuitum, M.chelonae, and M.abscessus are:

The stain that does not require heating the slide for better penetration of stain into the mycobacterial cell wall is known as the:

Microbial Taxonomy

Bacterial Genetics, Metabolism, and Structure

Host-Microorganism Interactions

Laboratory Safety

Specimen Management

Role of Microscopy

Traditional Cultivation and Identification

Nucleic Acid-Based Analytic Methods for Microbial Identification and Characterization

Immunochemical Methods Used for Organism Detection

Serologic Diagnosis of Infectious Diseases

Principles of Antimicrobial Action and Resistance

Laboratory Methods and Strategies for Antimicrobial Susceptibility Testing

Staphylococcus Micrococcus and Similar Organisms

Streptococcus Enterococcus and Similar Organisms

Bacillus and Similar Organisms

Listeria Corynebacterium and Similar Organisms

Erysipelothrix Lactobacillus and Similar Organisms

Nocardia Streptomyces Rhodococcus and Similar Organisms

Enterobacteriaceae

Acinetobacter, Stenotrophomonas, and Other Organisms

Pseudomonas, Burkholderia, and Similar Organisms

Rhizobium, Ochrobactrum, and Similar Organisms

Chryseobacterium, Sphingobacterium, and Similar Organisms

Alcaligenes, Bordetella Nonpertussis, Comamonas, and Similar Organisms

Vibrio, Aeromonas, Chromobacterium, and Related Organisms

Sphingomonas Paucimobilis and Similar Organisms

Moraxella and Related Organisms

Eikenella and Similar Organisms

Pasteurella and Similar Organisms

Actinobacillus, Aggregatibacter, Kingella, Cardiobacterium, Capnocytophaga, and Similar Organisms

Haemophilus

Bartonella and Afipia

Campylobacter, Arcobacter, and Helicobacter

Legionella

Brucella

Bordetella Pertussis, Bordetella Parapertussis, and Related Species

Francisella

Streptobacillus Moniliformis and Spirillum Minus

Neisseria and Moraxella Catarrhalis

Overview and General Considerations

Overview of Anaerobic Organisms

Obligate Intracellular and Non-culturable Bacterial Agents

Cell Walldeficient Bacteria: Mycoplasma and Ureaplasma

The Spirochetes

Laboratory Methods for Diagnosis of Parasitic Infections: Overview

Intestinal Protozoa

Blood and Tissue Protozoa

Other Protozoa

Intestinal Nematodes Roundworms

Tissue Nematodes Roundworms

Blood and Tissue Filarialnematodes

Intestinal Cestodes

Tissue Cestodes

Intestinal Trematodes

Liver and Lung Trematodes

Blood Trematodes

Overview of Fungal Identification Methods and Strategies

Hyaline Molds, Mucorales Zygomycetes, Dermatophytes, and Opportunitistic and Systemic Mycoses

Dematiaceous Melanizedmolds

Opportunistic Atypical Fungus: Pneumocystis Jiroveci