Detection of Ethambutol-Resistant Associated Mutations in Mycobacterium tuberculosis Isolates from Iran Using Multiplex Allele-Specific PCR

Tuberculosis is a serious global public health problem and its high prevalence is stron gly associated with the enhancement of drug resistance. In this study we demonstrate a multiplex allele-specific polymerase chain reaction (MAS)-PCR assay to simultaneously detect mutations in the first and third bases of the embB gene codon ۳۰۶ ATG in ethambutol (EMB) resistant isolates of Mycobacterium tuberculosis. A total of ۵۰۲۹ patients were sampled between ۲۰۱۰ and ۲۰۱۲. All the specimens were examined microscopically for acid-fast bacilli and cultured in Löwenstein-Jensen medium. The susceptibility tests were performed for culture positive samples and the EMB resistant M. tuberculosis isolates were subjected to MAS-PCR targeting embB gene in the codon ۳۰۶ ATG. Frothy eight of ۱۷۶ isolates were EMB-resistant. None of the isolates showed mutation in the first base of the codon ۳۰۶ ATG, but mutation in third base of the codon ۳۰۶ ATG was detected in ۱۴ isolates. We observed a correlation between culture-based phenotypic drug susceptibility and MAS-PCR method. The absence of mutation in resistant isolates can be attributed to possible involvement of other codon position at the same gene or other genes.

Keywords:

M .tuberculosis , Ethambutol , Drug resistant , Multiple Allele Specific PCR