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

Abstract

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. 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. 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. 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.