ABSTRACT
Global surveillance has shown that drug resistant [DR] tuberculosis [TB] is widespread. Prompt detection of Mycobacterium tuberculosis drug resistance is essential for effective control of TB. The most frequent mutations associated with Isoniazid [INH] resistance in Mycobacterium are substitutions at codons 315 in the katG gene and the mabA-inhA promoter region [15]. This survey evaluated INH resistant-associated mutations in order to determine rapid detection of TB resistance. Through a descriptive cross-sectional study total of 96 sputum specimens were digested, examined microscopically for acid-fast bacilli and inoculated into L wenstein-Jensen slants. Thereafter, the susceptibility and identification tests were performed on culture positive specimens. Subsequently, the strains were subjected to multiplex allele-specific polymerase chain reaction [MAS-PCR] targeting in the codons 315 in the katG gene and the mabA-inhA promoter region. Distinct PCR banding patterns were observed for different mutation profiles. Drug susceptibility testing revealed that out of 96 available isolates, 30 [31.3%] were susceptible, 36 [37.5%] had multi-drug resistance [MDR-TB] and 30 [31.3%] showed mono-drug resistance. In comparison with the culture-based phenotypic drug susceptibility test, the sensitivity and specificity of MAS-PCR assay for drug resistance-related genetic mutations were 76.7% and 71.4%, respectively. The correlation between MAS-PCR and culture-based phenotypic drug susceptibility testing findings was 99. 4%. The profile of the isolates suggests a significant number of different DR strains with a high frequency of mutations at codon 315 of the katG gene. MAS-PCR provides a rapid, simple and cost-effective method for detecting MDR-TB