Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Prevalence of pathogenic genes of Campylobacter jejuni as detected by PCR in strains isolated from humans and bovine feces Brenda Allan1, Debabrata Biswas1, Margaret L. Russell2, Cheryl Waldner3, Hugh Townsend1, Andrew Potter1, Lorne Babiuk1 and Sherry J Hannon3. 1Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon , SK, Canada, S7N 5E3 2Dep’t Community Health Sciences, Faculty of Medicine, University of Calgary, Calgary, AB, Canada, T2N 4N1 3Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5B4
Campylobacter jejuni is an important cause of bacterial gastroenteritis in humans. In rare cases the enteric disease is followed by the occurrence of Guillian-Barré syndrome, a serious neurological disease. Poultry are considered to be a primary source of human-pathogenic C. jejuni; however other domestic animals species may be important sources/reservoirs of this bacterium. In this study we have examined the feces of beef cattle for the presence of C. jejuni. Fresh cattle feces were collected from seven commercial feedlots (n=2800, 400 per feedlot) in Alberta, Canada during 2005. The feedlot cattle feces samples were cultured for Campylobacter using direct plating on Karmali agar. Preliminary results indicate that relatively high levels of Campylobacter species were present in cattle feces (76-95% positive cultures depending on feedlot). PCR analysis and the hippurate hydrolase test were used to determine which of the Campylobacter isolates were C. jejuni. Forty-nine C. jejuni isolates from feces were selected for further study. In addition, 50 human C. jejuni isolates were obtained from the Alberta Provincial Laboratory of Pubic Health. The sequenced strains NCTC11168, RM1221 and 81-1776 were included as controls in our study. We examined the isolates for the presence of 14 genes encoding putative virulence factors by PCR. These included genes implicated in adherence and colonization (flaC, cadF, docC, racR, jlpA, peb1 and dnaJ), in invasion (virB11, ciaB, pldA, and iamA) and in protection against harsh conditions (htrA, cbrA, and sodB). With the exception of the virB11 the genes examined were widely distributed in both the beef fecal isolates and the human isolates. Less than ten percent of the isolates contained all of the genes examined. Almost 60% of the isolates tested contained all of the genes examined except virB11. Only cadF was found in all isolates tested. In contrast, occasional isolates contained only between one and five of the genes examined. These data suggest that diversity in the profile of virulence genes exists. It also appears that there is no remarkable difference observed between cattle and human isolates. Further work using DNA genotyping will be undertaken to enhance our understanding about the diversity observed in these strains. |
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