Exploring multi-antibiotic resistance in Arcobacter butzleri isolates from a poultry processing plant in northern Italy: An in-depth inquiry

Arcobacter butzleri is a foodborne pathogen that has been identified in various animal-derived foods, notably in poultry meat. The prevalence of this bacterium in poultry underscores the need for comprehensive investigations into its dissemination within poultry meat processing plants. Such assessments are critical due to the potential cross-contamination that may occur, impacting the safety of the final food product. This study endeavours to evaluate the genomic similarity of 56 A. butzleri isolates obtained from chicken carcasses (specifically neck skins and caecum, post-slaughter) and equipment surfaces following cleaning and sanitizing procedures. All samples originate from a poultry slaughterhouse in Northern Italy. The genomic analysis includes single nucleotide polymorphism, average nucleotide identity, and core genome multi-locus sequence typing analysis, aiming to discern potential cross-contamination between carcasses and equipment. The study evaluates antibiotic resistance, biofilm production, and host cell colonization of A. butzleri strains through in vitro assays. Genomic dereplication reveals the presence of 31 distinct strains. Results elucidate that a portion of these strains is evident in multiple sources, indicative of cross-contamination even post-cleaning and sanitization. The in vitro tests underline multi-antibiotic resistance of A. butzleri with genes associated with antibiotic resistance, among them mexAB-oprM, showing a correlation to the observed resistance. This study establishes the colonization capability of A. butzleri strains on a human gut mucus-secreting cell model, suggesting a potential virulence factor. Detection of various putative virulence genes further supports the hypothesis of strains virulence potential. This study holds importance of A. butzleri as it unveils the antibiotic resistance and pathogenic capabilities inherent in this species, identifying associated genetic traits. Through comprehensive genomic analysis, it was conclusively validated instances of cross-contamination between various sources and equipment surfaces, underscoring the pervasive dissemination of this bacterium within a food processing plant and its persistence. This research serves as an exploration into the intricate dynamics of A. butzleri within poultry processing environments. It accentuates the imperative for stringent hygiene protocols and ongoing surveillance to curtail the risk of cross-contamination, thereby ensuring the safety of poultry products for discerning consumers.