Mycobacterium Tuberculosis

Question 1

Morphology of mycobacteria

Answer 1

1.non motile
2.non sporting
3.non capsulated
4.weakly gram +ve
5.straight or curved rod shaped
6.branching filamentous form

Question 2

Acid fast bacteria ppt-

Answer 2

Resist decolorization d/t-
1.high content of mycolic acid
2.integrity of cell wall

Question 3

Antigenic structures of M.TB

Answer 3

2 type of antigen-
1.cell wall (insoluble)antigen
2.cytoplasmic antigen

Question 4

Cell wall type of antigen

Answer 4

1. Peptidoglycan layer-maintain shape&rigidity
   2.aarabinogalactan layer
   3.mycolic acid layer- principal constituents,acid fast ppt,attaches to LCFA & reduce entry of antibiotics
   4.outermost layer- lipids,glycolipids &mycosides
   5.proteins- LAM and PIM IN PLASMA MEMBRANE

Question 5

LAM FUNCTION

Answer 5

1.helps survive within macrophages
2.used as target antigen for diagnosis of TB

Question 6

Risk factors of tb

Answer 6

1.overcrowding in poorly ventilated areas
2.low CMI- HIV INFECTION
3.BACILLARY LOAD- more than or equal to 10^4

Question 7

Clinical manifestations

Answer 7

1.pulmonary tb
2.extra pulmonary TB

Question 8

Pulmonary TB TYPES-

Answer 8

1.primary
2. Secondary

Question 9

Primary pulmonary tb

Answer 9

1.intial exogenous infection
2.mainly children
3.middle and lower lung lobe involvement
4.gohn focus
5. Lymph node involvement
6. Productive cough , pain,sweating,fever, weight loss

Question 10

Secondary pulmonary TB

Answer 10

1.exogenous reinfection
2.mainly in adult
3.no lymph node involvement
4.apical &post lobe of upper lung
5.assmann focus (Simon focus with central caesation)

Question 11

Extra pulmonary tb

Answer 11

Mostly in pt with TB &HIV
1. Lymph node -tubercular lympadenitis
2. Lung -pleural tuberculosis
3.respiratory tract
4.cns- tubercular meningitis (in children’s)

Question 12

HIV ASSOCIATED TB FEATURES

Answer 12

1.lymphatic
2.disseminated
3.meningitis
4.pleural

Question 13

Lab D

Answer 13

1.specimens collection-sputum & gastric aspirate in children
2.microscopy- ZN STAIN-Long slender,beaded ,&less uniformly stained red color acid fast bacilli
Fluorescent staining - mores sensitive
3.culture media - LJ MEDIUM (6-8 WKS)
4.IDENTIFICATION-MALDI TOF
ANTIGEN DETECTION -ICT
5.MOLECULAR METHODS-PCR DETECTION IS6110 GENE, CBNAAT, F LINE PROBE OF ASSAY.
6. DIAGNOSIS OF LATENT TB- mantoux test and IGRA

Question 14

Treatment

Answer 14

1.first line of drug (isoniazid, rifampicin,&ethambutol)
2.second line of drugs(linezolid &amikacin)

Question 15

Strategies of treatment

Answer 15

1. Multidrug therapy-combination of drugs
   2.short course chemotherapy( 6 months)
   3.two phase chemotherapy ( a)intensive phase & b)continuation phase)
   4.dots strategy