Mycobacterium

Cards (42)

  • What is the primary pathogenic mycobacterium discussed in the study material?
    1. tuberculosis
  • Why is it important to understand pathogenic mycobacteria?
    They are significant causes of disease in humans.
  • What are the key processes involved in the pathogenesis of mycobacteria?
    • Establishment of infection
    • Progression to disease
    • Transmission
  • What is the shape and structure of mycobacteria?
    They are unicellular and branched rods.
  • What type of staining is used for mycobacteria?
    Acid-fast staining.
  • What is the Ziehl-Neelsen stain used for?
    To stain mycobacteria.
  • What are the steps involved in the Ziehl-Neelsen staining process?
    1. Stain with carbol fuchsin.
    2. Destain with acid alcohol.
    3. Counterstain with methylene blue.
  • What color do mycobacteria stain in the Ziehl-Neelsen method?
    Red.
  • What is the significance of mycolic acid in mycobacteria?
    It contributes to the waxy cell wall, making them acid-fast.
  • How are mycobacteria classified based on their growth rate?
    • Fast growers: 1-2 days on plates (e.g., M. phlei, M. smegmatis).
    • Slow growers: several weeks to months (e.g., M. tuberculosis).
  • Which mycobacterium is closely related to tuberculosis and poses a zoonotic risk?
    1. bovis.
  • What disease does M. avium-intracellulare cause in humans?
    It is an opportunistic infection, especially common in HIV patients.
  • What disease is caused by M. leprae?
    Leprosy.
  • What is the global impact of tuberculosis?
    30,000 people die every week, and 2 billion are infected.
  • What are the common clinical manifestations of tuberculosis?
    Fever, weight loss, weakness, persistent cough.
  • What are the potential sites of TB infection in the body?
    • Central nervous system
    • Lymphatic system
    • Genitourinary system
    • Bones and joints
  • What happens to most people after a TB infection?
    They control the infection and may develop asymptomatic latent infection.
  • How does M. tuberculosis enter the body?
    Through aerosols that travel to the alveoli of the lungs.
  • What is the role of alveolar macrophages in TB infection?
    They engulf M. tuberculosis and can either clear or contain the infection.
  • What is the granulomatous response in TB infection?
    • Attracts more immune cells.
    • Damages tissue and forms granulomatous tubercle.
    • Can lead to latent infection.
  • What can happen if the granulomatous response fails to contain the bacteria?
    It can lead to reactivation of the infection.
  • What is the significance of the immune response in TB transmission?
    It is required for transmission and can damage the host.
  • What is the primary method of diagnosing TB?
    Microscopy of sputum for acid-fast rods.
  • What is the culture medium used for growing mycobacteria?
    Lowenstein-Jensen medium.
  • What is the role of PCR in TB diagnosis?
    It detects the presence of TB DNA.
  • What are the control strategies for TB?
    • Preventive vaccination.
    • Antibiotic treatment.
    • Diagnosis.
  • What is the purpose of the BCG vaccine?
    To prevent establishment of TB infection and disease.
  • What is the efficacy of the BCG vaccine in children?
    It protects against disseminated disease.
  • What is the challenge with treating the 2 billion people with asymptomatic TB infection?
    They cannot be treated effectively due to the lack of symptoms.
  • What are the first-line oral anti-TB drugs?
    • Isoniazid
    • Rifampicin
    • Ethambutol
    • Pyrazinamide
  • Why is multi-drug treatment required for TB?
    To prevent resistance development in bacteria.
  • What is the definition of MDR-TB?
    Resistant to at least rifampicin and isoniazid.
  • What is XDR-TB?
    Resistant to rifampicin, isoniazid, any fluoroquinolone, and at least one injectable second-line drug.
  • What is the treatment regimen for MDR-TB?
    • At least 4 potentially active drugs.
    • New drugs like Bedaquiline and Delaminid.
    • Repurposed drugs like Linezolid and moxifloxacin.
  • What is the global success rate for treating MDR-TB?
    55%.
  • What is the causative agent of leprosy?
    1. leprae.
  • How can M. leprae be cultured for study?
    In 9-banded armadillos and mouse footpads.
  • What percentage of individuals infected with leprosy develop clinical disease?
    5%.
  • What are the two clinical manifestations of leprosy?
    • Tuberculoid: mild disease with few bacilli.
    • Lepromatous: severe disease with many bacilli.
  • What is the primary treatment for lepromatous leprosy?
    Dapsone.