mycobacteria

• What is the shape of Mycobacteria?


  Unicellular and branched rods
• What type of bacteria are Mycobacteria classified as?


  Gram positive
• What is a key feature of the Mycobacteria cell wall?


  It contains sugars, proteins, and a lot of lipid
• What staining method is used for Mycobacteria?


  Acid fast staining using Ziehl Neelson stain
• What is the primary stain used in the Ziehl Neelson method?


  Carbol fuchsin
• What is the purpose of destaining in the Ziehl Neelson method?


  To remove excess stain using acid alcohol
• What color do Mycobacteria appear after the Ziehl Neelson staining process?


  Red
• What color do non-Mycobacteria appear after the Ziehl Neelson staining process?


  Blue
• How are Mycobacteria grouped based on their growth rates?


  • FAST growers: 1-2 days on plates (e.g., M.phlei, Msmegmatis)
  • SLOW growers: several weeks (e.g., M.tuberculosis, M.bovis)
• Which Mycobacterium is closely related to tuberculosis?


  1. bovis
• What is the primary pathogen associated with HIV among Mycobacteria?


  1. avium-intracellulare-scrofulaceum complex
• What is the causative agent of tuberculosis?


  1. tuberculosis
• What are the general clinical manifestations of tuberculosis?


  Fever, weight loss, weakness, persistent cough
• What causes the symptoms of tuberculosis?


  Result from the inflammatory response
• What type of infection is most common in tuberculosis cases?


  Pulmonary infection
• How can tuberculosis spread in the body?


  It may spread to the central nervous system, lymphatic system, genitourinary systems, bones, and joints
• What is the primary route of transmission for tuberculosis?


  Aerosol travels to alveoli of lungs
• What happens when M. tuberculosis is engulfed by alveolar macrophages?


  If activated, the host may clear the bacteria; if unactivated, bacteria survive and replicate
• What is a granulomatous tubercle?


  A structure formed when bacteria attract more cells and damage tissue
• What can happen to a tubercle over time?


  It can remain silent or allow release of viable bacteria leading to reactivation
• What does the inflammatory response correlate with in tuberculosis?


  It correlates with the degree of cavitation
• How does HIV affect the infectivity of pulmonary tuberculosis?


  It decreases infectivity in late HIV
• What role do steroids play in tuberculosis treatment?


  Steroids increase the rate of sputum clearance
• What are the methods for diagnosing tuberculosis?

  • Radiology
  • Microscopy of sputum for acid fast rods
  • Culture of sputum samples on specific media
  • PCR
  • Immunological T cell response to TB antigens

  
• What is the purpose of the Lowenstein Jenson medium in tuberculosis culture?


  To grow sputum samples while inhibiting other bacteria
• What is the goal of preventive vaccination for tuberculosis?


  To prevent establishment of infection and disease development
• What is the main antibiotic treatment for active tuberculosis?


  First line oral anti-TB drugs
• What are the first line oral anti-TB drugs?

  Isoniazid, Rifampicin, Ethambutol, Pyrazinamide
• What factors contribute to the varying efficacy of the BCG vaccine?


  Differences between vaccine sub-strains and genetic differences between populations
• What is the source of the BCG vaccine?


  Derived from M. bovis by serial passage
• What is the treatment regimen for new tuberculosis cases?


  First line oral anti-TB drugs for 6 months

  
• What is the definition of MDR-TB?


  Resistant to at least rifampicin and isoniazid
• What is the definition of XDR-TB?


  Resistant to rifampicin, isoniazid, any fluoroquinolone, and at least one injectable second line drug
• What is required for the treatment regimen of MDR-TB?


  At least 4 potentially active drugs
• What is one of the new drugs used for MDR-TB treatment?


  Bedaquiline
• What is the global success rate for treating MDR-TB?


  55%
• What are the treatment options for leprosy?


  • Dapsone is the most used antibiotic
  • Multidrug therapy may include clofazamine and rifampicin
  • Treatment for lepromatous leprosy may be for life
• What is the causative agent of leprosy?

  Mycobacterium leprae
• How many people were affected by leprosy in 1985 compared to now?


  15 million in 1985, now less than 0.5 million
• What is unique about the growth of Mycobacterium leprae?


  It is non-cultivatable but can be grown in 9 banded armadillos and mouse footpads