Objective: To determine and characterize inhA mutations of drug-resistant isolates of Mycobacterium tuberculosis.
Methods: PCR products of inhA of drug-resistant and susceptible isolates and H(37)R(v) were purified, cloned and analyzed by ABI 377 auto-DNA sequencing system.
Results: 11 out of 17 drug-resistant M. Tuberculosis isolates were detected having inhA variations. 10 out of the 11 strains with variations had at least one missense mutation. The variations consisted of point mutation (transition, transversion and deletion). Molecular mechanisms were different from strain to strain. 8 of 13 (62%) strains had both katG and inhA mutations. 18 variation positions and mechanisms different from previous report have been described.
Conclusion: These results suggested that binding sites decrease caused by inhA point mutations be associated with M. tuberculosis' resistance to INH and EMB.