TB

Question 1

Mainly caused by

Answer 1

M. tuberculosis

with occasional M.bovis involvment

Question 2

Which vaccine is given towards TB

Answer 2

BCG

A live, attenuated strain of bovine tubercle bacilli

Question 3

Method for TB microscopy

Answer 3

• Waxy coat, impermeabl to normal stain. use Ziehl-Neelsen
• Are acid fast.
• Acid/alcohol to the smear will rmove stain from any other organisms that arent acid fast

Question 4

Downside of AFB staining

Answer 4

Nearly always indicates TB, BUT relatively insensitive

level of detection: 10000 bacteria per ml sputum

Question 5

Diagnosing TB from culture

Answer 5

• Deep sputum preffered
• Grow slowly, need to supress commensal bacteria that could outgrow them
  
  • treated with shodium hydroxide to kill other organisms
• Use Lowenstein-Jensen medium
  
  • growth from 2 weeks onwards

Question 6

Treatment in M. TB

Answer 6

• Rifampicin, idonizid mainly
  
  • resistance becmoing a problem
• (Ethambutolm pyrazinamoide, streptomycin)

Question 7

Other mycobacterial infections

Answer 7

• M. leprae; leprosy
• M. ulcerans; necrotizing soft-tissue infection
• M. avium; disease in the immunocompromised