Overview of Clostridioides difficile in the poultry sector in France
Résumé
Clostridioides difficile is an opportunistic pathogen responsible for diarrhea and colitis, generally associated with antimicrobial treatments in humans. Potential reservoirs of C. difficile have been described up to now, in particular in animals and food. Recent studies have highlighted the contamination of poultry meat by C. difficile, with PCR-ribotypes similar to those involved in human infections. The objective of our study was to get an overview of C. difficile in the poultry sector in France from farm to retail. We focused on broiler production and collected 190 caecal contents from 21 broiler farms, 695 samples at the slaughterhouse (12 visits in 3 companies over one year) and 465 meat samples during one year at retail, including 194 chicken breasts without skin and 271 chicken thighs with skin. Detection of C. difficile was conducted using an enrichment step (ten-fold dilution of samples in BHI supplemented with taurocholate, cefoxitin and cycloserin) followed by isolation on ChromID. PCR-Ribotypes, detection of virulence genes and resistance to antimicrobials were then determined. C. difficile was detected in broiler caecal contents in 18 farms out of the 21 investigated, with a detection rate ranging from 10% to 78% in each farm. At the slaughterhouse level, 42 samples were positive, especially the scalding tank (58%) and plucking machine (45%) but it was not detected in meat samples. Finally, C. difficile was detected in 4 meat samples (0.9%) at retail, only in cutting parts with skin. A high genetic diversity was observed throughout the poultry sector with PCR-Ribotypes as 001, 005, 015, 002, 014 or 020, which are associated with human infections. Most strains (91.5%) have genes encoding Toxin A and B and the main detected antimicrobial resistance targeted clindamycin and tetracycline. While being largely detected in broiler chicken farms and at the beginning of the slaughter process, this study shows a low detection rate of C. difficile in the meat at retail. However, the presence of C. difficile in farms and early slaughter stages highlights the need for continuous monitoring and risk assessment to prevent potential contamination events and ensure food safety.
