Culture of Campylobacter jejuni with Sodium Deoxycholate Induces Virulence Gene Expression

• Published in: Journal of bacteriology Vol. 1909; no. 7; pp. 2286 - 2297
• Main Authors: Malik-Kale, P, Parker, C.T, Konkel, M.E
• Format: Journal Article
• Language: English
• Published: 2008
• Subjects: acid tolerance; acute course; bacterial contamination; bacterial infections; Campylobacter jejuni; campylobacteriosis; cell culture; cell invasion; deoxycholic acid; food pathogens; gene expression; Gram-negative bacteria; human diseases; microarray technology; microbial genetics; reverse transcriptase polymerase chain reaction; virulence
• ISSN: 1098-5530; 1098-5530

Campylobacter jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human food-borne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion, as shown by gentamicin protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC secreted the Cia proteins, as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene, as determined by β-galactosidase reporter, real-time reverse transcription-PCR, and microarray analyses. Microarray analysis further revealed that DOC induced the expression of virulence genes (ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrated that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation for identifying genes expressed by C. jejuni in response to in vivo-like culture conditions.