76 Questions
What is the approximate number of people who die from tuberculosis every week?
35,000
What percentage of tuberculosis cases involve the central nervous system, lymphatic system, genitourinary systems, bones, and joints?
15%
What is the primary way that M. tuberculosis is transmitted?
Through the air, via aerosol droplets
What is the outcome of TB infection in individuals with a healthy immune response?
The bacteria are contained, but not eliminated
What is the name of the bacteria that causes tuberculosis?
M. tuberculosis
What is the primary risk factor for developing tuberculosis?
Poverty
What is the result of a granuloma failing to contain bacteria?
Immediate lymphatic or hematogenous spread
What is the annual dose of BCG vaccine administered globally?
100 million
What is the purpose of adding antibiotics or malachite green to the medium in Lowenstein-Jensen culture?
To inhibit the growth of other bacteria
What is the goal of preventive vaccination in TB control?
To prevent establishment of infection and development of disease
What is the duration of first-line oral anti-TB drugs treatment for new and previously untreated cases?
6 months
What is the role of the immune response in TB transmission?
It is required for transmission
What is the definition of XDR-TB?
Resistant to rifampicin, isoniazid, any fluoroquinolone, and at least one of the three injectable second-line drugs
What is the number of potentially active drugs required for MDR-TB treatment?
At least 4
What is the function of radiology in TB diagnosis?
To detect granulomatous lesions
What is the effect of steroids on sputum clearance in TB patients?
They increase the rate of sputum clearance
What is the purpose of the first-line oral anti-TB drug pyrazinamide?
To treat new and previously untreated TB cases
What is the name of the vaccine derived from M. bovis?
BCG
What is the name of the new drug used to treat MDR-TB?
All of the above
What is the percentage of MDR/RR-TB in new TB cases?
Variable among countries
What is the duration required for culturing M. tuberculosis on Lowenstein-Jensen medium?
6 weeks
What percentage of infected individuals do not develop clinical disease?
95%
How often are the recommendations for DR TB treatment updated?
Every year
What is the primary antibiotic used to treat leprosy?
Dapsone
What is unique about the transmission of leprosy?
The exact mode of transmission is still unknown
What is the characteristic of the host response in tuberculoid leprosy?
Strong cellular immune response, low antibody
What is the effect of poor host resistance in lepromatous leprosy?
Formation of foam cell granulomas
What is the current treatment approach for lepromatous leprosy?
Multidrug therapy
What is the significance of the 9-banded armadillo in leprosy research?
It is used as a model organism for leprosy research
What is the effect of leprosy on the nervous system?
It leads to paralysis and anaesthesia
What is the primary characteristic of mycobacteria that distinguishes them from other bacteria?
Presence of lipid in their cell wall
What is the main difference between fast and slow growers in mycobacteria?
Growth rate on plates
Which of the following mycobacteria is a pathogen of fish and frogs?
M.marinum
What is the purpose of the Ziehl Neelson stain in mycobacteria identification?
To identify mycobacteria as acid-fast
What is the primary mode of transmission of M.tuberculosis?
Through inhalation of infected droplets
What is the primary characteristic of M.leprae?
It is a slow grower
Which of the following mycobacteria is closely related to M.tuberculosis?
M.bovis
What is the primary limitation of vaccination as a control strategy for mycobacterial diseases?
Variable efficacy against different strains
Mycobacterium avium-intracellulare-scofulaceum complex is an animal pathogen and opportunist of humans.
True
All mycobacteria are slow growers.
False
Mycobacterium ulcerans causes Buruli ulcer in humans.
True
Ziehl Neelson stain is used to identify all types of bacteria.
False
Mycobacterium marinum causes disease in fish and frogs.
True
Mycobacterium bovis is not related to M. tuberculosis.
False
All saprophytic mycobacteria are fast growers.
True
Mycobacterium leprae is not a human pathogen.
False
The bacteria M.paratuberculosis is a human pathogen.
False
Two billion people are infected with HIV.
False
Tuberculosis is a disease of wealth.
False
In most cases, tuberculosis is a pulmonary infection that spreads to other parts of the body.
True
The bacteria M.ulcerans is a pathogen of fish and frogs.
False
The outcome of TB infection is always death.
False
The immune response is required for transmission of TB
False
The granulomatous response always contains bacteria
False
Tuberculosis can only be diagnosed through radiology
False
The primary goal of antibiotic treatment in TB is to prevent transmission
False
The BCG vaccine is derived from M. tuberculosis
False
Steroids decrease the rate of sputum clearance in TB patients
False
Granuloma always remains walled off for years to decades
False
The clinical syndrome of TB only requires a partially intact immune response
False
The BCG vaccine has been proven to be 100% effective in preventing tuberculosis in humans.
False
The first-line oral anti-TB drugs are given to previously treated cases for 6 months.
False
XDR-TB is resistant to at least rifampicin and isoniazid, but not to fluoroquinolone.
False
The treatment regimen for MDR-TB requires at least 3 potentially active drugs.
False
The World Health Organization updates the recommendations for DR TB treatment every 5 years.
False
Bedaquiline is a repurposed drug used to treat MDR-TB.
False
The BCG vaccine is derived from M. tuberculosis.
False
Multi-drug treatment is required for tuberculosis because of the bacteria's ability to mutate and develop resistance.
True
Globally, the success rate in treating MDR TB is more than 70%.
False
Leprosy is always limited to the tropics.
False
The bacteria Mycobacterium leprae can be grown in cell cultures.
False
Dapsone is no longer used to treat leprosy due to its high resistance.
False
The host response in lepromatous leprosy is characterized by a strong cellular immune response.
False
Leprosy disease can be spread through epidemic fashion.
False
BCG vaccine is not effective in treating leprosy.
False
The primary characteristic of leprosy is the formation of tuberculoid granulomas.
False
Study Notes
Tuberculosis (TB)
- Global emergency: 35,000 deaths per week, 2 billion people infected, high incidence in HIV-infected individuals
- Disease of poverty
- Clinical manifestations:
- General: fever, weight loss, weakness, persistent cough
- Pulmonary infection: impairment of lung tissue, may spread to other parts of the body
- Other affected areas: central nervous system, lymphatic system, genitourinary system, bones and joints, disseminated (miliary TB)
Transmission, Protection, and Pathogenesis
- Aerosol travels to alveoli of lungs, engulfed by alveolar macrophages
- Host immune response:
- Activated: clears or contains bacteria
- Unactivated: bacteria survive and replicate in macrophages, attract immune cells, damage tissue, and form granulomatous tubercle
- Outcome of TB infection:
- Containment or clearance
- Disease progression
- Transmission
Mycobacteria
- Unicellular, branched rods, Gram-positive, complex cell wall with sugars, proteins, and lipids
- Acid-fast staining with Ziehl-Neelsen stain
- Grouping:
- Fast growers (1-2 days): M. phlei, M. smegmatis
- Slow growers (several weeks): M. tuberculosis, M. bovis, M. avium-intracellulare-scofulaceum complex
TB Control and Treatment
- Diagnosis:
- Radiology
- Microscopy of sputum for acid-fast rods
- Culture of sputum samples
- PCR
- Immunological – T-cell response to TB antigens
- Vaccination:
- Bacille Calmette-Guérin (BCG) – derived from M. bovis, avirulent, safe, inexpensive, and effective in experimental models
- Debated effectiveness in humans
- Antibiotic treatment:
- First-line oral anti-TB drugs: isoniazid, rifampicin, ethambutol, pyrazinamide
- Multi-drug treatment required due to resistance
AMR and Tuberculosis
- MDR-TB: resistant to at least rifampicin and isoniazid
- XDR-TB: resistant to rifampicin, isoniazid, any fluoroquinolone, and at least one of the three injectable second-line drugs
- Treatment regimen for MDR-TB: at least 4 potentially active drugs
- New drugs: bedaquiline, delamanid, linezolid
- Repurposed drugs: late-generation fluoroquinolone, injectable aminoglycoside, first-line drug with known susceptibility
Leprosy
- Causative agent: Mycobacterium leprae
- Non-cultivatable, but grows in 9-banded armadillos and mouse footpads
- Intracellular parasite, grows in macrophages and other cells
- Transmission unknown, but not epidemic
- Disease manifestations:
- Tuberculoid: few bacilli, mild disease, strong cellular immune response
- Lepromatous: severe disease, massive bacilli, poor cellular immune response
- Control of leprosy: vaccination with BCG, multidrug therapy with dapsone, clofazamine, and rifampicin
Tuberculosis (TB)
- Global emergency: 35,000 deaths per week, 2 billion people infected, high incidence in HIV-infected individuals
- Disease of poverty
- Clinical manifestations:
- General: fever, weight loss, weakness, persistent cough
- Pulmonary infection: impairment of lung tissue, may spread to other parts of the body
- Other affected areas: central nervous system, lymphatic system, genitourinary system, bones and joints, disseminated (miliary TB)
Transmission, Protection, and Pathogenesis
- Aerosol travels to alveoli of lungs, engulfed by alveolar macrophages
- Host immune response:
- Activated: clears or contains bacteria
- Unactivated: bacteria survive and replicate in macrophages, attract immune cells, damage tissue, and form granulomatous tubercle
- Outcome of TB infection:
- Containment or clearance
- Disease progression
- Transmission
Mycobacteria
- Unicellular, branched rods, Gram-positive, complex cell wall with sugars, proteins, and lipids
- Acid-fast staining with Ziehl-Neelsen stain
- Grouping:
- Fast growers (1-2 days): M. phlei, M. smegmatis
- Slow growers (several weeks): M. tuberculosis, M. bovis, M. avium-intracellulare-scofulaceum complex
TB Control and Treatment
- Diagnosis:
- Radiology
- Microscopy of sputum for acid-fast rods
- Culture of sputum samples
- PCR
- Immunological – T-cell response to TB antigens
- Vaccination:
- Bacille Calmette-Guérin (BCG) – derived from M. bovis, avirulent, safe, inexpensive, and effective in experimental models
- Debated effectiveness in humans
- Antibiotic treatment:
- First-line oral anti-TB drugs: isoniazid, rifampicin, ethambutol, pyrazinamide
- Multi-drug treatment required due to resistance
AMR and Tuberculosis
- MDR-TB: resistant to at least rifampicin and isoniazid
- XDR-TB: resistant to rifampicin, isoniazid, any fluoroquinolone, and at least one of the three injectable second-line drugs
- Treatment regimen for MDR-TB: at least 4 potentially active drugs
- New drugs: bedaquiline, delamanid, linezolid
- Repurposed drugs: late-generation fluoroquinolone, injectable aminoglycoside, first-line drug with known susceptibility
Leprosy
- Causative agent: Mycobacterium leprae
- Non-cultivatable, but grows in 9-banded armadillos and mouse footpads
- Intracellular parasite, grows in macrophages and other cells
- Transmission unknown, but not epidemic
- Disease manifestations:
- Tuberculoid: few bacilli, mild disease, strong cellular immune response
- Lepromatous: severe disease, massive bacilli, poor cellular immune response
- Control of leprosy: vaccination with BCG, multidrug therapy with dapsone, clofazamine, and rifampicin
Learn about the global impact of Tuberculosis, its symptoms, and affected areas of the body. Discover how it spreads and ways to protect yourself.
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