The Susceptibility of katG Ser315Thr Mycobacterium tuberculosis mutant Against Anti Tuberculosis Drugs

Mycobacterium tuberculosis resistant strains is a matter of great concern for TB control Program since no cure for some multi drug resistance TB (MDR-TB) cases. These strains could spread around the world, make a great challenges for control measures. Mycobacterium tuberculosis strains resistance to anti tuberculosis drugs is mainly caused by the alteration in several genes encoding the molecular targets. Mutation of katG at codon 315 especially Ser315Thr are responsible for INH resistance in a large proportion of TB cases. The aim of this study is to know the frequency of of katG Ser315Thr of M. tuberculosis mutant and the pattern of resistance to Anti TB drugs. The study design was observational laboratoric. Eighty fi ve M. tuberculosis INH resistant clinical isolates were screened for mutation of katGSer315Thr by using PCR-RFLP and DNA sequence analysis.The results showed that katG Ser 315Thr were identifi ed in 23 (27,05%) of INH resistance isolates. Frequency of MDR among the katG Ser315Thr mutants almost double than the non mutant. The result suggested that the the katG Ser315Thr mutation may play important role in the development of MDR-TB