Designing and comparison study of rapid detection methods of resistance to injectable drugs in clinical strains of Mycobacterium tuberculosis

In this study، some molecular methods were designed for rapid detection of resistance to kanamycin and amikacin. Among 120 clinical isolates of mycobacterium tuberculosis، 70 strains were selected for evaluation of possible mutations. A PCR-RFLP method was designed for detection of wild type (using enzyme ajii) and mutant from (BstFNI enzyme) of the isolates. Furthermore، allele specific method (as PCR) was designed for detection mutations in codons 1401 and 1402 gene rrs. Some selected isolates were sequenced. In PCR-RFLP method، among the 70 strains examined by BstFNI enzyme، could detect 17 mutant strains among 24 phenotypicaly resistant and 44 non-mutant isolates from 46 susceptible isolates. The sensitivity of this method was %70. 83 and specificity was %95. 65 on the other hand، 12 mutant from 20 resistant strains and 29 non-mutant strains from 32 susceptible strains were detected by AjiI enzyme. The sensitivity and specificity of this method was 60 and %90. 62، respectively. In MAS PCR، 3 mutants from 6 resistant strains and 12 non-mutants from 17 resistant strains were detected. The sensitivity of this method was 50 and specificity was 70. 58. Results of sequencing method confirmed the results of molecular methods. Discussion and PCR-RFLP method by BstFNI enzyme was the best method for rapid detection of Mycobacterium tuberculosis resistant to second-line injectable drugs and was recommended for routine use.