Identification of novel oxa-134-like β-lactamases in acinetobacter lwoffii and acinetobacter schindleri isolated from chicken litter

Abstract

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.