Objective: To develop a new multiplex allele-specific polymerase chain reaction (MAS-PCR) assay to detect the main mutations in the rifampin resistance dependent region, which has been reported to account for the majority of clinic Mycobacterium tuberculosis resistant to rifampin.
Methods: Based on the sequence of rpoB gene, three specific primers were designed for the MAS-PCR to detect the most common mutations in codons 531, 526, 516 of rpoB gene.
Results: The purified DNA preparations of 91 clinical strains of Mycobacterium tuberculosis were used to optimize the PCR. The mutations in codon 531, 526, 516 were detected by the MAS-PCR. Compared with the results of direct sequencing of rpoB gene, no mutation was detected in the sensitive strains. For rifampin-resistant strains, the total sensitivity was 81.5% (66/81).
Conclusions: MAS-PCR is a new molecular method with a high sensitivity and specificity, which can be used to detect the 3 main mutations of rpoB gene rapidly and economically. It can be used in clinical laboratories to detect the rifampin-resistant strains of Mycobacterium tuberculosis.