deoxycholic-acid and Salmonella-Infections--Animal

We investigated the mechanism responsible for bile susceptibility in three deoxycholate-sensitive (DCs) strains of Salmonella enterica subspecies enterica serovar Pullorum isolated in 1958 in Japan. Of the genes encoding the AcrAB-TolC efflux system, the expression of acrB mRNA was 10-fold lower in the DCs strains than in a deoxycholate-resistant (DCr) strain, whereas those of the acrA and tolC genes were two-fold lower. These results suggested that low expression of acrB was strongly correlated with bile susceptibility in the DCs strains. In addition, the increase in tolC expression levels was not detected in the DCr mutants derived from the DCs strains, suggesting that difference in the expression levels of tolC is not associated with bile susceptibility.

Topics: Animals; Bacterial Proteins; Carrier Proteins; Chickens; Deoxycholic Acid; Down-Regulation; Drug Resistance, Bacterial; Japan; Membrane Transport Proteins; Microbial Sensitivity Tests; Poultry Diseases; Salmonella enterica; Salmonella Infections, Animal; Serotyping

Passage through the digestive tract exposes Salmonella enterica to high concentrations of bile salts, powerful detergents that disrupt biological membranes. Mutations in the wecD or wecA gene, both of which are involved in the synthesis of enterobacterial common antigen (ECA), render S. enterica serovar Typhimurium sensitive to the bile salt deoxycholate. Competitive infectivity analysis of wecD and wecA mutants in the mouse model indicates that ECA is an important virulence factor for oral infection. In contrast, lack of ECA causes only a slight decrease in Salmonella virulence during intraperitoneal infection. A tentative interpretation is that ECA may contribute to Salmonella virulence by protecting the pathogen from bile salts.

Topics: Animals; Antigens, Bacterial; Bacterial Proteins; Bile Acids and Salts; Deoxycholic Acid; Disease Models, Animal; Drug Resistance, Bacterial; Female; Humans; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Mutation; Salmonella Infections, Animal; Salmonella typhimurium; Virulence

Topics: Animals; Cell Line; Deoxycholic Acid; DNA Transposable Elements; Genes, Bacterial; Macrophages; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Microscopy, Electron; Mutagenesis; Mutagenesis, Insertional; Phenotype; Salmonella; Salmonella Infections, Animal; Salmonella typhimurium; Virulence