Activation of latent Escherichia coli virulence factors by Campylobacter jejuni

Abstract

Campylobacter jejuni is the most common cause of bacterial gastroenteritis, and while typically self-limiting, C. jejuni infections are associated with post-infectious intestinal disorders, including inflammatory bowel disease and irritable bowel syndrome. This study sought to determine if C. jejuni induces virulence in commensal, non-invasive E. coli. Expression of adhesin, flagella, hemolysin, biofilm formation, and antibiotic resistance genes were increased in E. coli upon exposure to C. jejuni-conditioned media. Atomic force microscopy demonstrated E. coli was more adherent to human colonic epithelial cells when exposed to C. jejuni-conditioned media. C. jejuni and C. jejuni-conditioned media also induced E. coli flagella expression. In vitro, this altered E. coli phenotype disrupted TLR4 expression and induced IL-8 secretion. These data suggest C. jejuni and C. jejuni-conditioned media can induce virulence in non-invasive, commensal E. coli, and this contributes to host inflammation. These results provide a novel mechanism for post-infectious complications.