Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/2005
Publication Date: 11/20/2005
Citation: Dassanayake, R.P., Stryker, C.J., Johnson, R.K., Gebhart, C.J., Post, K.W., Hinkley, S., Muraoka, W.T., Wesley, I.V., Duhamel, G.E. 2005. The U.S. Porcine Campylobacter coli are negative for cytolethal distending toxin activity [abstract]. Research Workers in Animal Diseases Conference Proceedings. p. 88.
Technical Abstract: A novel toxin, designated cytolethal distending toxin (CDT), has been found among several bacterial pathogens, including Campylobacter species. The genes encoding CDT are present in C. coli isolated from humans and animals, however, with the exception of a recent report suggesting high CDT activity among strains isolated from pigs in Denmark, CDT activity has not been found in C. coli from other hosts. We examined the reference C. coli strain ATCC 49941 and 40 C. coli strains isolated from pigs on commercial farms in Iowa (n=10), Minnesota (n=10), Nebraska (n=10), and North Carolina (n=9) for the presence of cdtB gene and CDT activity. The identity of each strain was confirmed on the basis of phenotypic and genotypic analyses. As expected the cdtB gene was present in all of the strains by PCR amplification of a partial sequence using degenerate and gene-specific oligonucleotide primers. Co-incubation of either HeLa or H407 cells with whole-cell lysates obtained from each strain did not elicit cellular changes characteristic of CDT activity, as determined by either examination using light microscopy or quantitative G2/M phase cell cycle arrest using flow cytometry. Therefore, C. coli isolated from pigs in major swine producing regions of the United States do not produce CDT. The C. coli cdtB gene-specific PCR assay developed in the present study might be of assistance for differentiating C. coli from toxigenic Campylobacter clinical isolates.