INHA and tuberculosis: The frequency of the katG315Thr mutation was significantly higher in MDR-TB compared to the other drug resistant form of MTB isolates (67.9%.vs.48.7%; χ2, 4.736; p, 0.030), while inhA-15T mutations did not differ significantly between these two major drug susceptibility groups (20.8%.vs.21.8%; χ2, 0.020; p, 0.887).