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Identification of Surface Structures of Campylobacter jejuni Involved in the Colonization of Poultry

 Brenda Allan¹, Kingsley Amoaka¹ & Susantha Gomis²

1.  Veterinary Infectious Disease Organization,                                                  University of Saskatchewan, Saskatoon

2.  Dept. of Veterinary Pathology                                                                                  Western College of Veterinary Medicine                                                                         University of Saskatchewan, Saskatoon

Campylobacter jejuni is the most common cause of bacterial gastroenteritis in North America. The handling and consumption of poultry products is a major risk factor for C. jejuni infections in humans.

The objectives of our research program include:

1.      Development of suitable animal models for colonization of poultry by C. jejuni.

2.      Investigation of the interaction of the bacterium and the host.

3.      Development of vaccination strategies to prevent colonization of poultry by C. jejuni.

 Day-old chicks are not normally colonized by C. jejuni.  Around two weeks of age colonization of birds is first detected. By the time of slaughter between 30 and 100% of flocks will be colonized. It is assumed that a few birds are colonized. The bacteria are shed in the feces and spread to other birds.

 We have developed two models for the colonization of day-old chicks. The strain of C. jejuni that has been sequenced (NCTC111786) was used in these studies. The bacteria were grown for 18 hours under reduced oxygen conditions on Mueller-Hinton agar. For use in the challenge the bacterial cells were resuspended in normal saline and diluted to the appropriate concentration. Cloacal swabs were obtained from individual birds and cultured on Karmali agar, a medium that is very selective for Campylobacter, to monitor the spread of colonization.

 In the first model, all birds are challenged with an oral dose of C. jejuni in a 0.5 mL volume. As few as 10⁶ colony forming units of C. jejuni, were capable of colonizing all birds by 7 days of age (Fig. 1.).

 We have developed a second model for the horizontal transfer of C. jejuni within a group of birds. At day of age 20 percent of the birds were challenged with 10⁸ CFU’s of C. jejuni NCTC11186. By day three 40% of the birds were colonized and by day five 85% of the birds were colonized. On day 7 all birds in the group were positive for C. jejuni. The birds that were initially challenged remained colonized throughout the experiment (Fig. 2.).

 Using a different strain of C. jejuni (CJ26) we determined that higher doses of bacteria (up to 10¹⁰ CFU’s) were needed for colonization to occur. In addition, horizontal transfer of infection occurred only rarely.

All birds were challenged on day 0 and cloacal swabs were done on day 3, 5, and 7 to detect colonization.

Five birds were challenged with 10⁸ CFU’s of bacteria. Fifteen birds were put in contact with the challenged birds. All birds were monitored for colonization on Day 3, 5, and 7.

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Last modified: 5/28/2009