Drug resistance and toxigenic properties of Campylobacter jejuni and Campylobacter coli isolated from the intestinal tract of chickens on Prince Edward Island

Campylobacter jejuni and C. coli were isolated from 119 (51.5%) of 231 samples of chicken cecal contents.

Plasmid DNA was isolated from two tetracycline resistant $\rm (TET\sp{r})$ C. jejuni strains RO 28 and RO 33 from broiler chickens using three different protocols: rapid TELT mini-prep, rapid mini-prep with heat, and Promega$\rm\sp{TM}$ mini-prep. Of these three only Promega$\rm\sp{TM}$ mini-prep gave a consistent yield of plasmid DNA. The two $\rm TET\sp{r}$ isolates RO 28 and RO 33 each had a plasmid DNA in the Agarose gel electrophoresis corresponding to the 45 Kbp $\rm TET\sp{r}$ plasmid and a smaller band corresponding to the 12 Kbp of the marker DNA. A $\rm TET\sp{r}$ strain of C. jejuni ATCC 43502 with a 45 Kbp a $\rm TET\sp{r}$ plasmid was used as a control.

The production of enterotoxin by C. jejuni and C. coli was evaluated by adding cell-free filtrates of 48 hour cultures of the bacteria to CHO-K1 cells grown in Ham's F12 media in 96 well plates. Two human C. jejuni strains 4483 and 6704 were included in each test as positive and negative controls respectively. Of the 119 isolates of C. jejuni strains 4483 and 6704 were included in each test as positive and negative controls respectively. Of the 119 isolates of C. jejuni and C. coli that were tested, 56 (47%) produced toxins that caused elongation of the CHO-K1 cells. Strong toxin effect was observed at dilutions of 1:2, 1:4 and 1:8.

In conclusion, understanding the rate of carriage of drug resistant and toxigenic C. jejuni by chicken is crucial to the development of control measures to reduce the contamination of the pathogen on poultry meat and thus lower the risk of infection to consumers. (Abstract shortened by UMI.).