Objective: To establish a simple, rapid and sensitive hybridization method for detecting drug-resistance relevant gene mutation in Mycobacterium tuberculosis.
Methods: Fourteen single-strand specific probes designed to detect mutated and/or wild rpoB gene in Mycobacterium tuberculosis were spotted and fixed on nylon membranes, and PCR products labeled with biotin were obtained by using down-stream primer labeled with biotin, then hybridized and analyzed with streptavidin-HRP and TMB.
Results: Twenty-three rifampin-resistant Mycobacterium tuberculosis isolates and 11 rifampin-sensitive isolates were analyzed. The gene mutations were consistent with the DNA sequencing and the in vitro susceptibility test in 30/34 and 28/34 of the isolates, respectively. Mutations of Ser-531 were present in 11 of the 23 rifampin-resistant isolates, followed by His-526, Leu-533, and no mutation was found in 13 isolates, including 2 rifampin-resistant isolates. Mutations in loci 516 and 513 were not detected.
Conclusion: Reverse dot-blot hybridization may be of potential use for the rapid diagnosis of rifampin-resistant tuberculosis.