MCQ on Mycobacterium spp (Medical Microbiology) - Tuberculosis, diagnosis and treatment of tuberculosis

                     Multiple Choice Question on Tuberculosis and Leprosy

1) Mycobacteria are acid-fast positive bacteria because they consist of:
a) lipopolysaccharide in the bacterial cell wall
b) mycolic acid in the bacterial cell wall
c) lipids
d) Both B and C options above

2) Which of the following first-line antibiotics are usually resistant to Mycobacterium tuberculosis?
a) Isoniazid and ciprofloxacin
b) Isoniazid and Rifampin
c) Rifampin and ciprofloxacin
d) Rifampin and streptomycin

3) What is the mechanism responsible for antibiotic resistance seen in M. tuberculosis?
a) Mutations in DNA gyrase gene
b) Alterations in beta-lactamase
c) Mutations in the catalase-peroxidase gene
d) Alterations in RNA polymerase

4) All of the following are examples of selective media/agar used for the culture of M. tuberculosis, Except?
a) Inspissated egg media
b) Middlebrook 7H10/7H11 media with antibiotics
c) Dubos media
d) Middlebrook 7H10 media without antibiotics

5) Which of the following statement is true about the tuberculin test and purified protein derivative (PPD)?
a) The presence of intradermal skin induration is observed 6 to 8 hours after being applied
b) The redness of skin or erythema is also measured while reading the tuberculin test
c) A positive tuberculin test means that a person was infected with M. tuberculosis in the past and continues to carry the viable organism
d) A positive PPD test indicates that a person can never be infected with M. tuberculosis

6) Which of the following pathogen has a shorter incubation period and is a nontuberculous mycobacterium?
a) Mycobacterium ulcerans
b) Mycobacterium avium complex (MAC)
c) Mycobacterium leprae
d) Mycobacterium fortuitum

7) All of the following are the symptoms of pulmonary tuberculosis, EXCEPT?
a) Weakness and fatigue
b) Decreased body temperature
c) Weight loss
d) Severe prolonged cough with sputum or blood

8) Select all the distinguishing properties of Mycobacterium tuberculosis
a) A major respiratory pathogen
b) It is an acid-fast bacteria 
c) The cell wall consists of mycolic acid
d) A fast grower and usually easy to grow in artificial media

9) Which of the following bacteria causes lung infection and is the most common non-tuberculous mycobacterial infection associated with AIDS patients?
a) Mycobacterium avium complex
b) Mycobacterium leprae
c) Mycobacterium gordonae
d) Mycobacterium gastri

10) A 50 year old patient who had his kidney transplant 6 months ago visited the hospital with pneumonia-like symptoms for the last 2 months. 

The chest x-ray examination revealed a typical feature of tuberculosis infection, a photochromogenic (orange pigment when exposed to UV light) acid-fast rod bacterium was isolated from the sputum sample. 

Name the possible identified bacteria?
a) Mycobacterium avium
b) Mycobacterium tuberculosis
c) Mycobacterium kansasii
d) Mycobacterium leprae

11) All of the given are the distinguishing characteristics of Mycobacterium leprae, EXCEPT:
a) It is an acid-fast bacillus
b) It cannot be isolated in-vitro culture method
c) It can be isolated by only the in-vivo culture method
d) It is a human and as well as animal pathogen

12) Which one of the following acid-fast rod bacilli can take up to ten years for its growth in host cells and causes skin infections?
a) Mycobacterium tuberculosis
b) Mycobacterium leprae
c) Mycobacterium avium complex
d) Nocardia spp

13) Other than Mycobacterium tuberculosis which of the following bacteria causes tuberculosis infection in animals and can be transmitted to humans by consumption of milk and other animal products?
a) Mycobacterium bovis
b) Mycobacterium leprae
c) Mycobacterium ulcerans
d) Mycobacterium abscessus

14) The initial therapy of tuberculosis includes which type of antibiotics/drug regimen from the following options?

a) Streptomycin and rifampin
b) Isoniazid, streptomycin, and ethambutol
c) Rifampin, isoniazid, and ciprofloxacin
d) Isoniazid, rifampin, pyrazinamide, and ethambutol

15) What is the interferon-gamma release assays (IGRAs) for TB bacteria?
a) Blood test for the detection of the release of interferon-gamma by T-cells
b) Sputum test for the detection of genetic material of TB bacteria
c) The test used as an alternative tuberculin skin test in latent tuberculosis
d) The test used as an alternative tuberculin skin test in the active tuberculosis

16) The specimen of Mycobacterium tuberculosis should be handled with safety and caution. 

Which of the following statement is correct regarding the laboratory diagnosis of Tuberculosis?

a) It is one of the most common laboratory-acquired infection

b) Sputum is the common specimen used for the diagnosis

c) Culture method is the rapid detection method for TB bacteria

d) None of the above 

 

17) A 16-year-old boy from a remote region in Australia visited the hospital, a painless lesion on the left side of the neck with a yellowish-white papule first appeared about 2 months ago. The lesion grew larger as the days passed. He did not have any underlying disease condition and no other clinical symptoms. 

A tissue sample was taken for the biopsy examination, gram staining and acid-fast staining showed gram-positive rods, after 4 weeks of incubation transparent colonies appeared on the culture media. 

Name the possible pathogen?

a) M. ulcerans

b) M. bovis

c) M. avium

d) M. leprae

18) From the above question (17), which of the following infection is caused by the pathogen?

a) Chagas disease

b) Hansen's disease

c) Buruli ulcer

d) Peptic ulcer

19) All of the following are the rapid and confirmatory staining techniques for the identification of Mycobacterium spp, Except?

a) Ziehl neelsen method

b) Fluorochrome stain

c) Dorner method

d) Kinyoun method

20) The nitrate reduction test is one of the primary biochemical tests in identifying M. tuberculosis. Which of the following biochemical test is useful in the identification of lipase producing M. kansasii and M. marinum?

a) Tween 80 hydrolysis test

b) Neutral red test

c) Tellurite reduction test

d) Bile esculin test

21) What is a Mantoux test?

a) Sputum sample microscopy

b)Tuberculin skin test (TST)

c) Blood test

d) Urine test

22) Which of the following test is used for the detection of genetic material of TB bacteria in sputum sample?

a) Interferon-gamma assays IGRAs

b) Tuberculin skin test

c) Venereal Disease Research Laboratory test (VDRL)

d) Nucleic acid amplification tests (NAATs)

Multiple Choice Answers:

1-d) Both B and C options above  

2-b) Isoniazid and Rifampin
3-c) Mutations in the catalase-peroxidase gene
4-d) Middlebrook 7H10 media without antibiotics
5-c) A positive tuberculin test means that a person was infected with M. tuberculosis in the past and continues to carry the viable organism
6- d) Mycobacterium fortuitum
7- b) Decreased body temperature
8- a), b), and c)

It is slow-growing bacteria and usually difficult to grow in the lab using artificial media

9-a) Mycobacterium avium
10-c) Mycobacterium kansasi
11-d) It is a human and as well as animal pathogen
12-b) Mycobacterium leprae
13-a) Mycobacterium bovis
14-d) Isoniazid, rifampin, pyrazinamide, and ethambutol
15-a)Blood test for the detection of the release of interferon-gamma by T-cells

16-b) Sputum is the common specimen used for the diagnosis

17-a) M. ulcerans

It is present in aquatic environment and soil, causes skin infections in humans.

b) M. bovis can cause tuberculosis in cattle, c) M. avium can cause pulmonary infections, a pathogen affecting both mammals and birds.

d) M. leprae, causes skin infections in humans, symptoms appear in the later stage of the life (after 20 and above)

18-c) Buruli ulcer

19-c) Dorner method

20-a) Tween hydrolysis test

21- b)Tuberculin skin test (TST)

Involves injecting a small amount of purified protein derivative (PPD) under the skin and observing the reaction after 48-72 hours. A positive TST indicates exposure to TB but may not necessarily mean active infection.

22. d) Nucleic acid amplification tests (NAATs)

a) Interferon-gamma assays IGRAs is blood test for TB bacteria identification, b) Tuberculin skin test is a skin test for detection of TB bacteria, c) Venereal Disease Research Laboratory test (VDRL) test is a screening test for Syphilis diagnosis.