The Periplasmic Trehalase Affects Type 1 Fimbria Production and Virulence of Extraintestinal Pathogenic Escherichia coli Strain MT78
Abstract
Extraintestinal pathogenic Escherichia coli (ExPEC) is responsible for various infections outside the gastrointestinal tract in humans and other animals. ExPEC strain MT78 is invasive to various nonphagocytic cells and highly virulent in vivo To identify genes required for invasion of nonphagocytic cells by this strain, we applied signature-tagged mutagenesis to generate a library of mutants and tested them for invasion of avian fibroblasts. Mutants showing reduced cellular invasion included those with insertions in the fim operon, encoding type 1 fimbriae. Another attenuated mutant showed a disruption in the treA gene, which encodes a periplasmic trehalase. The substrate of TreA, trehalose, can be metabolized and used as a carbon source or can serve as an osmoprotectant under conditions of osmotic stress in E. coli K-12. We generated and characterized mutant MT78ΔtreA In contrast to the wild type, MT78ΔtreA was able to grow under osmotic stress caused by 0.6 M urea but not in minimal M9 medium with trehalose as the only carbon source. It presented decreased association and invasion of avian fibroblasts, decreased yeast agglutination titer, and impaired type 1 fimbria production. In a murine model of urinary tract infection, MT...Continue Reading
References
Trehalose metabolism in Escherichia coli: stress protection and stress regulation of gene expression
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