Identification of the enteropathogens Campylobacter jejuni and Campylobacter coli based on the cadF virulence gene and its product

Campylobacter jejuni and Campylobacter coli are common causes of gastroente ritis in humans. Infection with C, jejuni or C. coli is commonly acquired b y eating undercooked chicken. The goal of this study was to develop specifi c detection assays for C. jejuni and C, coli isolates based on the cadF vir ulence gene and its product. The cadF gene from C. jejuni and C, coli encod es a 37-kDa outer membrane protein that promotes the binding of these patho gens to intestinal epithelial cells. A fragment of approximately 400 bp uas amplified from 38 of 40 (95%) C. jejuni isolates and 5 of 6 (83.3%) C, col i isolates with primers designed to amplify an internal fragment of the cad F gene. PCR was then used to amplify Campylobacter DNA from store-bought ch ickens. A 400-bp band was amplified from 26 of the 27 chicken carcasses tes ted by the PCR-based assay, The CadF protein was detected in every C. jejun i and C. coli isolate tested, as judged by immunoblot analysis with a rabbi t anti C. jejuni 37-kDa serum. In addition, methanol-fixed samples of whole -cell C,jejuni and C, coli Here detected with the rabbit anti-37-kDa serum by using an indirect-immunofluorescence microscopy assay. These findings in dicate that the cadF gene and its product are conserved among C. jejuni and C. coli isolates and that a PCR assay based on the cadF gene may be useful for the detection of Campylobacter organisms in food products.