55 Questions
Which of the following is true about mycobacteria?
They are associated with human disease
Which mycobacteria is responsible for causing leprosy?
M. leprae
What are nontuberculous mycobacteria (NTM)?
Mycobacteria that are environmental organisms
Which test is used as a screening of infected subjects?
Intradermal tuberculin test
What is the mechanism of action of ethambutol?
Interferes with the synthesis of arabinogalactan
What can cause the reactivation of latent tuberculosis?
Immune-suppression
What is the mechanism of action of Daptomycin?
Binds irreversibly to the cytoplasmic membrane
Which classification group of NTM includes M. avium and M. intracellulare?
Slow-growing nonpigmented mycobacteria
What is the main mediator of NTM lung disease?
Gastroesophageal reflux disease
What is the main route of transmission for M. tuberculosis?
Inhalation of aerosols produced by coughing of infected individuals
How do mycobacteria inhibit the fusion between phagosome and lysosome?
By encoding proteins in the RD1 region
What is the main characteristic of mycobacteria?
They are rod-shaped bacteria that grow only in the presence of oxygen
Which of the following mycobacteria is responsible for causing tuberculosis?
M. tuberculosis
What are nontuberculous mycobacteria (NTM)?
Mycobacteria other than tuberculosis responsible for opportunistic infections especially in immunocompromised patients
Which of the following is a characteristic of scotochromogenic mycobacteria?
They produce carotenoids in response to light
What are the four main manifestations of NTM disease?
Pulmonary disease, Disseminated disease, Lymphatic disease, Skin/soft tissue disease
What is the main mediator of NTM lung disease?
Gastroesophageal reflux disease
What is the mechanism of pathogenicity of Mycobacterium tuberculosis?
Ability to resist intracellular killing of macrophages
Which of the following is true about latent tuberculosis?
It can reactivate in case of immune-suppression
What is the purpose of decontaminating the expectoration with a solution containing sodium hydroxide?
To eliminate other bacteria present in the expectoration
What is the mechanism of action of isoniazid and ethionamide?
They affect the synthesis of mycolic acid
What is the purpose of the intradermal tuberculin test?
To verify the presence of immune responses against M. tuberculosis
What is the main characteristic of mycobacteria?
They are rod-shaped bacteria
Which of the following mycobacteria is responsible for causing leprosy?
M. leprae
What are nontuberculous mycobacteria (NTM)?
Mycobacteria that are environmental organisms
Which mycobacteria group includes M. kansasii and M. marinum?
Slow-growing photochromogens
What is the main mechanism of pathogenicity of Mycobacterium tuberculosis?
Resistance to intracellular killing of macrophages
What is the main route of transmission for M. tuberculosis?
Aerosol produced by coughing of infected individuals
What is the purpose of biofilm formation in NTM?
To colonize unfavourable habitats
Which of the following is a characteristic of latent tuberculosis?
Granuloma undergoes fibrosis and calcification
What is the purpose of the decontamination process with sodium hydroxide in the diagnosis of tuberculosis?
To eliminate other bacteria present in the expectoration
Which of the following drugs inhibits the synthesis of cell wall in mycobacteria?
Cycloserine
What is the mechanism of action of Daptomycin against bacteria?
It binds irreversibly to the cytoplasmic membrane
Which of the following is a characteristic of mycobacteria?
They are rod-shaped bacteria
Which of the following mycobacteria is responsible for causing leprosy?
M. leprae
What is the collective term used for environmental mycobacteria responsible for opportunistic infections in immunocompromised patients?
MOTT
What is the Runyon classification scheme of NTM based on?
Color of carotenoids produced
What are the four main manifestations of NTM disease?
Pulmonary disease, Disseminated disease, Lymphatic disease, Skin/soft tissue disease
What is the main mechanism of pathogenicity of Mycobacterium tuberculosis?
Ability to resist intracellular killing of macrophages
What is a granuloma?
A structure formed by activated lymphocytes surrounding infected macrophages
What is the purpose of the intradermal tuberculin test?
To screen for latent tuberculosis
What is the mechanism of action of isoniazid and ethionamide against mycobacteria?
They affect the synthesis of mycolic acid
What is the difference between latent tuberculosis and active tuberculosis?
Latent tuberculosis is asymptomatic and active tuberculosis is symptomatic
What is the mechanism of action of cycloserine against mycobacteria?
It inhibits two enzymes involved in cell wall synthesis
Which of the following is NOT a characteristic of mycobacteria?
Production of endospores
Which species of mycobacteria is responsible for causing tuberculosis in humans?
M. tuberculosis
What is the collective term used for environmental mycobacteria responsible for opportunistic infections in immunocompromised patients?
MOTT
Which of the following is NOT a group in the Runyon classification scheme of NTM?
Slow-growing pigmented mycobacteria
What is the main route of transmission for Mycobacterium tuberculosis?
Airborne
What is the purpose of the intradermal tuberculin test?
To diagnose latent tuberculosis
What is the mechanism of pathogenicity of Mycobacterium tuberculosis?
Ability to resist intracellular killing of macrophages
Which of the following is true about extrapulmonary tuberculosis?
It is caused by the migration of mycobacteria to other organs
What is the purpose of the intradermal tuberculin test?
To diagnose latent tuberculosis
What is the mechanism of action of ethambutol against mycobacteria?
It interferes with the synthesis of arabinogalactan
What is the main difference between latent tuberculosis and active tuberculosis?
Latent tuberculosis is asymptomatic and cannot be transmitted, while active tuberculosis is symptomatic and can be transmitted
Study Notes
Mycobacteria Characteristics
- Mycobacteria inhibit the fusion between phagosome and lysosome.
Types of Mycobacteria
- Mycobacterium leprae is responsible for causing leprosy.
- Mycobacterium tuberculosis is responsible for causing tuberculosis.
Nontuberculous Mycobacteria (NTM)
- NTM includes M.avium and M.intracellulare.
- NTM includes M.kansasii and M.marinum.
- NTM is the collective term used for environmental mycobacteria responsible for opportunistic infections in immunocompromised patients.
- The Runyon classification scheme of NTM is based on pigmentation.
- The four main manifestations of NTM disease are:
- Pulmonary disease
- Lymph node disease
- Skin and soft tissue disease
- Disseminated disease
Mechanism of Action of Drugs
- Isoniazid and ethionamide inhibit the synthesis of mycolic acid in mycobacteria.
- Ethambutol inhibits the synthesis of arabinogalactan in mycobacteria.
- Daptomycin disrupts the bacterial cell membrane.
- Cycloserine inhibits the synthesis of bacterial cell wall.
Tuberculosis
- The main route of transmission for M. tuberculosis is airborne transmission.
- Reactivation of latent tuberculosis can occur due to a weakened immune system.
- Latent tuberculosis is a state of persistent infection without symptoms.
- Active tuberculosis is a state of active infection with symptoms.
- The intradermal tuberculin test is used as a screening test for infected subjects.
- The purpose of decontaminating the expectoration with a solution containing sodium hydroxide is to isolate mycobacteria.
Pathogenesis
- The main mechanism of pathogenicity of Mycobacterium tuberculosis is the inhibition of fusion between phagosome and lysosome.
- A granuloma is a structure formed in response to mycobacterial infection, consisting of immune cells and collagen.
Diagnosis
- The purpose of the intradermal tuberculin test is to diagnose latent or active tuberculosis.
Test your knowledge on mycobacteria, a group of rod-shaped bacteria that are obligate aerobes, do not produce endospores, and are associated with human disease. Learn about the different species, including M. tuberculosis, and their characteristics in this quiz.
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