Campylobacter jejuni and Campylobacter coli: prevalence, contamination levels, genetic diversity and antibiotic resistance in Italy

Abstract

A research was carried out in Italy with the aim of assessing Campylobacter contamination in broilers from breeding to slaughter, of defining the genetic diversity of isolates and their antibiotic resistance. Sampling was carried out in a slaughterhouse, and in farms representative of the most common broiler production in Italy. At farm, the 78.8% (95% C.I.: 74.5%‑82.5%) of cloacal samples tested positive for Campylobacter spp. C. jejuni showed higher prevalence in winter than in spring and summer (p < 0.00001, χ2 = 32.9), while C. coli showed an opposite trend (p < 0.00001, χ2= 41.1). At slaughterhouse, the 32.3% (95% C.I.: 30.2%‑35.2%) and the 23.9% (95% C.I.: 21.7%‑26.3%) of skin samples tested positive for C. jejuni for C. coli, respectively. C. coli showed higher prevalence than C. jejuni at washing (p < 0.05, χ2 = 11.11) and at chilling (p < 0.05, χ2 = 9.26). PFGE revealed high heterogeneity among isolates. Some clones were identified within the same farm in more than one season, suggesting environmental conditions able to support their persistence; other clones resulted to be spatially distant, suggestive of cross‑contamination. Both Campylobacter species showed high resistance to nalidixic acid and ciprofloxacin, while resistance to erythromycin was more frequent in C. coli than C. jejuni (p < 0.05; χ2 test).

Keywords

• Broiler carcasses
• Campylobacter
• Contamination levels
• Production chain
• PFGE