Identification of novel OXA-134-like β-lactamases in Acinetobacter lwoffii and Acinetobacter schindleri isolated from chicken litter.

Background: Various food-producing animals have been recognized in recent years as a potential reservoir for the spread of antibiotic resistant bacteria that may pose a risk to human health and therefore their dissemination in the food production chain needs to be assessed.

Methods: In this study, 450 boot swabs from chicken farms were analyzed for the presence of antimicrobial resistance with a focus on β-lactams resistance in Acinetobacter species.

Results: Two β-lactamase-encoding genes were first time identified in Acinetobacter lwoffii and Acinetobacter schindleri isolates. The deduced amino acid sequence of OXA-496 shared 93.8% identity with OXA-363. The second OXA-134-like enzyme, OXA-537, had the highest sequence identity (97.8%) with OXA-235 and OXA-237.

Conclusions: The results of this study illustrate the occurrence of new OXA-134-like β-lactamases, called OXA-496 and OXA-537, carrying strains of Acinetobacter lwoffii and Acinetobacter schindleri in chicken farm litter, and highlight the possible role of Acinetobacter as a reservoir of resistance genes.