Ciprofloxacin-resistant Campylobacter in broiler chicken in Canada

Effect of the polysaccharide capsule and its heptose on the resistance of Campylobacter jejuni to innate immune defenses

Campylobacter jejuni is a commensal in many animals but causes diarrhea in humans. Its polysaccharide capsule contributes to host colonization and virulence in a strain- and model-specific manner. We investigated if the capsule and its heptose are important for interactions of strain NCTC 11168 with various hosts and their innate immune defenses. We determined that they support bacterial survival in Drosophila melanogaster and enhance virulence in Galleria mellonella. We showed that the capsule had limited antiphagocytic activity in human and chicken macrophages, decreased adherence to chicken macrophages, and decreased intracellular survival in both macrophages. In contrast, the heptose increased uptake by chicken macrophages and supported adherence to human macrophages and survival within them. While the capsule triggered nitric oxide production in chicken macrophages, the heptose mitigated this and protected against nitrosative assault. Finally, the C. jejuni strain NCTC 11168 elicited strong cytokine production in both macrophages but quenched ROS production independently from capsule and heptose, and while the capsule and heptose did not protect against oxidative assault, they favored growth in biofilms under oxidative stress. This study shows that the wild-type capsule with its heptose is optimized to resist innate defenses in strain NCTC 11168 often via antagonistic effects of the capsule and its heptose.

Canadian integrated program for antimicrobial resistance surveillance: Retail food highlights, 2003-2012

Background

The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) is a collaborative, integrated program designed to track antimicrobial resistance (AMR) among enteric bacteria isolated from various livestock commodities along the food-producing continuum ("farm to fork") and in humans.

Objective

To provide a summary of the prevalence and trends in AMR among select bacteria isolated from raw, fresh chicken, pork, and beef in 2012 at the retail food level and to link these data with other findings from CIPARS.

Methods

Meat samples were collected from randomly selected geographic areas across Canada weighted by population for subsequent isolation of bacteria and interpretation of the associated AMR profiles. Salmonella, Campylobacter and generic Escherichia coli (E. coli) were tested in chicken, and E. coli was tested in beef and pork. Data were analyzed for 2012 and temporal and regional trends were examined between 2003 and 2012 by province/region.

Results

Overall, resistance levels to Salmonella in retail chicken varied widely by region and year. For example, ceftiofur resistance to Salmonella in retail chicken was significantly lower in 2012 than in 2004 in Ontario and in Québec; however, among all regions sampled, resistance was significantly higher in 2012 compared to 2006. Across all regions sampled, resistance to Campylobacter in retail chicken was relatively low in 2012 (<16%) with the exception of tetracycline resistance. In 2012, ciprofloxacin resistance to Campylobacter in chicken declined in British Columbia but significantly increased in Ontario, compared to 2011. In 2012, β-lactam resistance to E. coli in retail beef remained low (≤1%) and was also relatively low comparable to previous years in pork.

Conclusion

In Canada, as is the case worldwide, there is evidence of resistance to medically important antimicrobials among bacteria from retail meats. Resistance among organisms isolated from poultry, beef, and pork at the retail food level is characterized by wide variation over time and across different regions.