Genomic and Antimicrobial Surveillance of Campylobacter Population in Italian Poultry

Abstract

Campylobacter is one of the most common foodborne diseases worldwide with increasing rates of antibiotic resistance. Most cases of campylobacteriosis can be traced back to the consumption of poultry meat. Despite many efforts to reduce contamination in farms and in slaughterhouses, the persistence of this pathogen in poultry products remains a problem. This study aimed to evaluate the genetic diversity and antibiotic resistance of 542 C. jejuni and C. coli in Italian poultry, in the framework of two National Monitoring Programs. Genomes were screened for antibiotic resistance, virulence determinants and contextualized within a global collection of C. jejuni. ST2116, ST2863 and ST 832 were the most prevalent and significantly associated with Italian poultry. A worrying increase in resistance to quinolones, fluoroquinolones and tetracycline was observed in C. jejuni, while an increased occurrence of multidrug resistant (MDR) strains and strains resistant to macrolides was detected in C. coli. Low resistance rates were found for aminoglycosides. Molecular resistance determinants were consistent with the phenotypic resistance for tetracycline and quinolones. In silico analysis revealed 119 genes associated with virulence factors, with a notably higher prevalence of some genes in ST2863 genomes. This study highlights the increased resistance to macrolides and the emergence of MDR strains for C. coli, the genetic basis of AMR and the predominance of two genotypes among Campylobacter strains isolated from the Italian poultry farms.

Phenotypic Antimicrobial Resistance Profiles of Human Campylobacter Species Isolated in Northwest Italy, 2020–2023

“…Antimicrobial resistance to aminoglycosides (gentamicin and streptomycin) was less frequent (5.4%), roughly similar to previous studies where the resistance to gentamicin and streptomycin was low (0.7% and 2.4% on average, respectively) in C. jejuni and C. coli isolates from human samples [ 13 , 14 ]. Conversely, we observed low rates of resistance to erythromycin (3.2%), another CIA, supporting previous data that indicated low resistance in C. jejuni from human and animal samples [ 12 , 13 , 14 ]. However, higher rates have been reported for C. coli isolates from human samples (8.5%), similar to our findings, and animals (range, 4.4% to 35.7%) [ 14 ].…”

“…The antimicrobial resistance of Campylobacter species has increased worldwide [ 12 ] largely due to antimicrobial overuse in humans and in food-producing animals. Certain antimicrobials have been used extensively to treat Campylobacter infection in humans.…”

Antibiotic resistance, plasmids, and virulence-associated markers in human strains of Campylobacter jejuni and Campylobacter coli isolated in Italy

“…These strains were isolated in different years, suggesting they did not originate from an outbreak but were potentially acquired from a common source. Recent studies have indicated that ST-2116 and ST-2863 are the most prevalent STs isolated from broilers in Italy, exhibiting genetic homogeneity ( Di Giannatale et al, 2019 ; Marotta et al, 2023 ). This suggests that human infections caused by these clones, which are extensively circulating in Italy, are likely linked to broilers and the consumption of contaminated poultry meat and related food products.…”