ABSTRACT
Objective To study the rapid detection of mycobacterium tuberculosis resistance to streptomycin by reverse dot blot hybridization technique. Methods The oligonucleotide probes of streptomycin-resistant genes (rpsL and rrs) were prepared and dropped on nitrocellulose membrane. The target DNA fragments of M. tuberculosis clinical isolates were labeled with biotin by PCR amplification, and then hybridized with the oligonucleotide probes on the membranes. PCR-SSCP and PCR-direct sequencing (PCR-DS) techniques were used to detect the target fragment of M.tuberculosis as control. Results In 53 M. tuberculosis clinical isolates, the consistent rate of three detection methods was 100%. Both the SSCP mapping of rpsL and rrs genes and the results of membrane hybridization in 9 drug-sensitive strains were identical to those in M. tuberculosis standard strain H37Rv. Of 44 streptomycin-resistant strains, 33 strains had AAG→AGG mutation at the codon 43 of rpsL gene, 6 strains had A→C mutation at the 513 site of rrs gene, 1 strain had A→T mutation at the 513 site of rrs gene, and the detection rate of the target genes mutation was 90 9%. In 53 M.tuberculosis clinical isolates, 40 resistant strains and 9 sensitive strains to streptomycin could be detected using dot blot hybridization and the consistent rate with the in vitro susceptibility test was 92 6%(49/53). Conclusion The reverse dot blot hybridization technique showed high sensitivity and specificity to detect Mycobacterium tuberculosis resistance to streptomycin. It possessed the simple and rapid characteristics, and could be used to detecte streptomycin-resistant M.tuberculosis clinical strains.