Mycobacterium 2

• What type of bacteria is Mycobacterium leprae?

  Acid fast bacilli
• What disease is caused by Mycobacterium leprae?

  Leprosy or Hansen’s disease
• What is the generation time of Mycobacterium leprae?

  12-14 days
• Can Mycobacterium leprae be grown in vitro?

  No, it cannot be grown in vitro
• Where can Mycobacterium leprae be grown?

  In the footpad of mice and Armadillo
• What type of disease is leprosy?

  Chronic granulomatous disease
• What areas of the body does leprosy affect?

  Peripheral nerves and superficial tissues
• What is the estimated prevalence of leprosy worldwide?

  Less than 300,000 cases
• In how many countries are 85% of leprosy cases found?

  9 countries
• Which regions have the highest prevalence of leprosy cases?

  6 in Africa, 2 in Asia, and 1 in Latin America
• Is leprosy a common cause of mortality?

  No, it is rarely a cause of mortality
• What are some consequences of leprosy?

  Disabilities, disfigurement, and stigma
• What is the transmission method of leprosy?

  Unknown, but possible nasal droplets and direct inoculation through the skin
• What is the incubation period for leprosy?

  2 to 7 years, can be decades
• In which cells does Mycobacterium leprae replicate?

  In macrophages and Schwann cells
• What are the two distinct forms of leprosy?

  Tuberculoid leprosy and lepromatous leprosy
• What characterizes tuberculoid leprosy?

  Strong cell mediated immunity limits the growth of bacilli
• What is the lepromin skin test result in tuberculoid leprosy?

  Positive
• What are the clinical features of tuberculoid leprosy?

  Hypopigmented skin patches and anesthetic skin lesions
• Which nerves are typically thickened in tuberculoid leprosy?

  Ulnar, radial, median common peroneal, and auricular nerves
• What are the clinical features of lepromatous leprosy?

  Symmetrical, extensive skin lesions and thickening of the skin
• What is leonine facies associated with lepromatous leprosy?

  Fascial thickening, loss of eyebrows, and destruction of the nasal bridge
• What is the treatment for leprosy?

  Combination of Dapsone, Rifampin, and Clofazimine for 2 years
• What type of mycobacteria causes tuberculosis-like disease?

  Environmental organisms
• How is infection from other mycobacteria acquired?

  From environmental sources; no case-to-case transmission
• What are the characteristics of infections caused by other mycobacteria?

  Pulmonary cavitations and can be disseminated
• Who is primarily affected by infections from other mycobacteria?

  AIDS patients and patients with chronic pulmonary diseases
• What is the treatment for infections caused by other mycobacteria?

  Azithromycin + rifabutin and ethambutol
• What is Mycobacterium scrofulaceum associated with?

  Cervical lymphadenopathy in young children (scrofula)
• What does Mycobacterium marinum cause?

  Fish tank granuloma
• What is Buruli ulcer caused by?

  Mycobacterium ulcerans
• What is the characteristic of Mycobacterium fortuitum infection?

  Injection site abscess
• What are the key differences between tuberculoid and lepromatous leprosy?

  • Tuberculoid leprosy:
  • Strong cell mediated immunity (CMI)
  • Few bacilli present
  • Granulomas with giant cells
  • Positive lepromin skin test
  • Lepromatous leprosy:
  • Weak CMI response
  • Large number of bacilli
  • Significant tissue destruction
  • Negative lepromin skin test
• What are the clinical features of leprosy?

  • Tuberculoid leprosy:
  • Hypopigmented skin patches
  • Anesthetic skin lesions
  • Thickened superficial nerves
  • Lepromatous leprosy:
  • Symmetrical extensive skin lesions
  • Thickening of the skin
  • Leonine facies
  • Loss of digits and limbs
• What are the diagnostic methods for leprosy?

  • Specimen collection:
  • Skin or nasal scraping
  • Staining:
  • ZN stain for acid fast bacilli
  • Skin biopsy and histopathology:
  • Characteristic foam cells
  • Lepromin skin test:
  • Positive in tuberculoid leprosy
  • Negative in lepromatous leprosy