Multiple-antibiotic-resistant active efflux system gene identification and sequential analysis of Salmonella typhi

Objective: To detect by PCR and sequence the multiple antibiotic resistant efflux acrB gene in Salmonella typhi 275(a clinically isolated strain) and its induced resistant mutant OM2(RG1),182(RG2). Methods: The acrB gene of Salmonella typhi 275,OM2 and 182 were identified by PCR with the primers designed from Genebank(No. AL627267) and the DNA fragments were sequenced to confirm the existence of acrAB gene. Results: All the 3 strains ( Salmonella typhi 275,OM2 and 182) were acrB gene positive with 449 bp by PCR. Comparing with sequence of Salmonella typhi in the Genebank there were just 2 senseless base mutations in Salmonella typhi 275 and OM2 acrB (99.55% identity), 100% identity with the same amino acids. There were 2 bases insertation and 2 bases senseless mutation in Salmonella typhi 182 with no amino acids analysis because of the confused sequence. Conclusion: Multiple antibiotic resistant active efflux system exist in Salmonella typhi which is the bases of high level resistance and multiple antibiotic resistantce.