Rapid detection of multidrug-resistant Mycobacterium tuberculosis by multiplex allele-specific polymerase chain reaction

Abstract

OBJECTIVE: To evaluate a multiplex allele-specifi c polymerase chain reaction (MAS-PCR) to detect multidrugresistant tuberculosis (MDR-TB) clinical isolates and to describe the main mutations conferring resistance to isoniazid (INH) and rifampicin (RMP). DESIGN: Drug-resistant Mycobacterium tuberculosis clinical isolates were tested to detect mutations using MAS-PCR. The genes involved were katG, inhA promoter and rpoB. RESULTS: Among 193 clinical isolates included in the study, 52.6% of the INH-resistant isolates presented a mutation in the katG (315) gene, 28.1% in the inhAP (−15) and 3.0% in both. For the rpoB gene, 60% of the RMP-resistant isolates showed a mutation in codon 531, 17.5% in 526 and 2.5% in 516. Results were compared with those obtained by sequencing, and 100% concordance was obtained for the detection of the mutation in katG (315), 94.1% for inhAP (−15), and 97.8% for rpoB. The global concordance between both methods was 98%. CONCLUSIONS: The MAS-PCR system allowed the simultaneous and rapid detection of approximately 80.0% of the drug-resistant clinical isolates. This method could be used as a rapid and simple screening tool to detect drug-resistant TB in clinical practice.