Genetic diversity and antimicrobial resistance profiles of Campylobacter coli and Campylobacter jejuni isolated from broiler chicken in farms and at time of slaughter in central Italy

Aims: Genetic diversity and antimicrobial resistance of Campylobacter coli and Campylobacter jejuni were investigated along the broiler chicken production chain in central Italy. Methods and Results: Campylobacter sp. isolated from cloacal swabs in farms (n = 116) and from the neck skin of chilled and eviscerated carcasses at slaughter (n = 24) were identified as C. coli (n = 99) and C. jejuni (n = 41) by multiplex PCR. Characterization by single amplified fragment length polymorphism (s-AFLP) revealed a specific genotype of Campylobacter for each farm. Minimal inhibitory concentration showed high prevalence of fluoroquinolones (70%), tetracycline (70%) and erythromycin (30%) resistance among C. coli isolates. Campylobacter jejuni isolates showed lower prevalence of fluoroquinolone (39%) and tetracycline (10%) resistance, and all isolates were susceptible to erythromycin. The S-AFLP types of the C. coli and C. jejuni isolates were associated with their antimicrobial resistance profiles (P < 0·001). Conclusions: The genetic diversity detected in Campylobacter isolates suggested that a specific genotype was harboured in each farm. A considerable number of C. coli isolates were resistant to erythromycin. Significance and Impact of the Study: Campylobacter coli was detected more frequently than C. jejuni in contrast to common findings for poultry. The high prevalence of 30% resistance to erythromycin in C. coli strains isolated from poultry is worrisome, as this is the first antibiotic of choice to treat human campylobacteriosis.