Mycobacterium Tuberculosis

Question 1

TB (5):

Answer 1

• Cause by M. tuberculosis.
• Slow-growing, acid fast.
• Obligate aerobe.
• Invades macrophages.
• 2 forms: Primary and secondary.

Question 2

Primary TB:

Answer 2

• Usually mild.
• Formation of granulomas followed by caseation.
• In immunocompromised individuals —> miliary TB.

Question 3

Secondary TB:

Answer 3

• Delayed-type hypersensitivity.

Question 4

M. tuberculosis (4):

Answer 4

• Gram + like cell wall.
• Acid fast, slow growing.
• Resistance to drying and chemicals.
• Waxes in cell wall.

Question 5

M. tuberculosis virulence factors (5):

Answer 5

• Can grow inside macrophages and monocytes.
• LLO homologue allows escape from phagocytic vesicle.
• Prevents acidification of the phagosome.
• Mycolic acids produced are toxic.
• TNF-alpha provoked by cell wall components causes lung damage.

Question 6

TB treatment:

Answer 6

6 Months:

• Rifampin
• Isoniazid
• Streptomycin
• Ethambutol

Question 7

M. leprae (3):

Answer 7

• Resides in armadillos.
• Unable to be grown on medium.
• 2 presentations:
  
  • Tuberculoid leprosy - milder - CMI
  • Lepratomous leprosy - severe - No CMI

Question 8

Lepromatous leprosy:

Answer 8

• Multibacillary, growth of bacteria is unimpeded.
• Skin lesions.
• Cell mediated immunity is deficient. Th2 response.
• High infectivity.

Question 9

Leprosy treatment:

Answer 9

2 Years:

• Dapsone
• Rifampin
• Clofazimine