Mutation in which of the following genes is responsible for development of INH resistance in mycobacteria?
KatG (catalase peroxidase) conves INH (prodrug) to its active form which fuher inhibits inhA and KasA gene which leads to inibition of synthesis of mycolic acid (present in bacterial cell wall) leading to cell death. The most common mechanism which confers high level INH resistance is by mutation of the catalase-peroxidase (KatG) gene so that the bacilli do not generate the reactive metabolite of INH. This type of resistance cannot be overcome therefore INH should be stopped. DRUG RESISTANCE MUTATION IN GENE Rifampicin rpoB Isoniazid katG and inhA Ethambutol embB Pyrazinamide pncA
KatG
embB
pncA
rpoB
Mycobacterial Diseases (TB, Leprosy and MAC)