Survival and virulence properties of multiple antibiotic-resistant Salmonella Typhimurium under simulated gastrointestinal conditions

초록

The transit tolerance and relative gene expression (acrA, acrB, tolC, stn, hilA and ompD) were observed in antibiotic-sensitive Salmonella Typhimurium (ASST) and antibiotic-resistant S. Typhimurium (ARST) exposed to simulated gastric juices (pH 2.0, pH 3.0 and pH 5.0) for 1 or 4 h, followed by small intestinal juices (0.1% and 0.5% bile salts) for 2 h. The relative expression of acrA, acrB, tolC, stn, hilA and ompD in the ARST was upregulated after exposure to simulated gastrointestinal juices. The expression of AcrAB-TolC efflux system in ARST was highly correlated with the expression of stn and hilA encoding virulence factor and regulator. The cross-protective effect was observed in ARST against the gastric acid and bile salts. The AcrAB-TolC involved in enhanced survival and virulence potential, resulting in increased in pathogenicity of ARST. This study provides useful information for assessing the gastrointestinal transit tolerance and virulence potential of multiple antibiotic-resistant pathogens.

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