mycobacteria (17)

• What is the genus of the bacterium with high lipid content in its wall?

  Mycobacterium
• What accounts for 60% of the wall weight of Mycobacterium?

  Mycolic acids
• What is the acid-alcohol resistant character of Mycobacterium demonstrated by?

  Ziehl-Neelsen staining
• What type of respiration do Mycobacterium species require?

  Strict aerobes
• What type of pathogens are Mycobacterium classified as?

  Facultative intracellular pathogens
• What type of culture media is enriched for Mycobacterium growth?

  Media enriched with iron and lipids
• How is growth detected more rapidly in Mycobacterium?

  In liquid media
• What are the characteristics of the lipid wall of Mycobacterium?

  • High lipid content
  • Non-permeable to hydrophilic molecules
  • Acid-fast bacteria require heat for staining
  • Resistant to disinfectants, detergents, and antibiotics
• What is the staining process for Acid Fast Bacteria?

  Carbol fuchsin, HCl + alcohol, methylene blue
• What color do Acid-Fast Bacteria stain in Ziehl-Neelsen stain?

  Pink-red
• What is the significance of the cord factor in Mycobacterium?

  It is a pathogenicity factor
• What do other glycolipids in Mycobacterium do?

  Inhibit phagosome-lysosome fusion
• What is the Mantoux test used for?

  Skin hypersensitivity test
• What are the classifications of Mycobacteria?

  • Mycobacterium tuberculosis complex (slow growth)
  • Mycobacterium leprae (non-culturable)
  • Non-tuberculous mycobacteria:
  • Fast growth (before 7 days)
  • Slow growth (after 7 days)
• Which species is part of the Mycobacterium tuberculosis complex?

  1. tuberculosis
• What was one of the top causes of death in 2019?

  Tuberculosis (TB)
• What is a significant public health crisis related to TB?

  Multidrug-resistant TB
• What socioeconomic factors are associated with TB?

  Poor socioeconomic status and overcrowding
• How did the SARS-CoV-2 pandemic affect TB care?

  1.4 million fewer received TB care
• What can favor the reactivation of TB?

  AIDS
• How is TB primarily transmitted?

  Pflügge drops
• What happens during primary TB infection?

  Asymptomatic for 3-10 weeks
• What occurs after inhalation of Pflügge drops?

  1. tuberculosis reaches the alveoli
• What is the role of macrophages in TB infection?

  Transport bacilli to lymph nodes
• What immune response occurs in most TB cases?

  A cellular immune response destroys bacteria
• What are common symptoms of TB disease?

  Anorexia, weight loss, night sweats
• What is the most common location for TB disease?

  The lungs
• What is the risk of developing TB in infected individuals?

  5-10% will develop TB
• What tests are used for latent TB infection diagnosis?

  Mantoux test and IGRAs
• What is the purpose of the Mantoux test?

  To detect hypersensitivity reaction
• What is the first line of treatment for TB?

  Combination of 3 or 4 drugs
• Why is long-term treatment necessary for TB?

  To eliminate all mycobacteria
• What are the types of drug-resistant TB strains?

  MDR, XDR, and TDR strains
• What are the objectives of TB prevention?

  1. Avoid infection:

  • Respiratory isolation of active patients
  • Search and treatment of new cases
  • Socio-economic improvements
  • Primary prophylaxis with isoniazid
  • BCG vaccine

  1. Secondary prophylaxis:

  • Treat latent infection with isoniazid
• What is Mycobacterium leprae also known as?

  Hansen Bacillus
• Why is Mycobacterium leprae difficult to study?

  It cannot be cultured on artificial media
• What is the primary disease caused by Mycobacterium leprae?

  Leprosy (Hansen disease)
• What are the clinical manifestations of tuberculoid leprosy?

  Hypopigmented plaques and sensory loss
• What characterizes lepromatous leprosy?

  High number of cutaneous lesions
• What are the characteristics of non-tuberculous mycobacteria?

  • Atypical and/or environmental mycobacteria
  • Low virulence, require predisposing factors
  • Increasing isolation from clinical specimens
  • Associated with lung infections and skin issues