A rapid screening program on the resistance to streptomycin and ethambutol in Mycobacterium tuberculosis isolates by PCR melting curve analysis

OBJECTIVE: To evaluate the effects of PCR melting curve analysis assay on a rapid screening program regarding the resistance of Mycobacterium tuberculosis (MTB) clinical isolates to streptomycin and ethambutol. METHODS: A total of 331 clinical isolates of MTB had been collected since 2007-2009 in Shenzhen. Mutations at codon 306, 378-380, 406 and 497 of embB gene, codon 43, 88 of rpsL gene, and 513-517, 905-908 region of rrs gene were detected by PCR melting curve analysis. Results were compared with that of conventional drug susceptibility test. RESULTS: Compared to drug susceptibility test, sensitivity, specificity and accuracy for streptomycin resistance were 78.6%, 90.1% and 86.7%, respectively while 83.0%, 93.3% and 91.8%, respectively for ethambutol resistance detected by PCR melting curve analysis. PCR melting curve method was in good agreement with drug susceptibility test. CONCLUSION: PCR melting curve analysis on genetic regions associated with resistance to streptomycin and ethambutol seemed to be a rapid, specific and closed-tube method so it could be used for detection of streptomycin and ethambutol resistance in MTB.