Abstract: Multidrug-resistant (MDR) bacteria in farm environments can be transferred to humans through the food chair and occupational exposure, Enterococcus infections caused by linezolid resistant enterococci (LRE) are becoming more challenging to treat as their resistance to antibiotics intensifies. Therefore, this study investigated the molecular epidemiology, phenotypic and genomic characterization of enterococci in seven species of farm animals (sheep, chicken, swine, camel, cattle, equine, pigeon) anal swab from Xinjiang, China by agar dilution method, polymerase chain reaction (PCR), whole-genome sequencing (WGS) and bioinformatics analysis. A total of' 771 samples were collected, 599 (78 %) were contaminated with Enterococcus spp., among which Enterococcus faecalis (350/599) was dominant, Antimicrobial susceptibility testing showed that high resistance was observed in rifampicin (80%), tetracvcline,(71%), doxycvcline (71%), and ervthromycin (69%), The results of PCR showed the highest prevalent antibiotic resistance genes (ARGs) were aac(6')-aph(2") (85 %), followed by tet(M) (73 %), erm(B) (62 %), and aph(3')-Ⅲa (61 %). Besides, 29 optrA-carrying E. faecalis isolates belonging to 13 STs (including 3 new alleles) were detected, with ST714 (31 %, 9/29) being the dominant ST type. The phylogenetic tree showed that optrA-carrying E. faecalis prevalent in the intensive swine farm is mainly caused by clonal.
Keywords: Antibiotic resistance, Enterococcus spp., optrA , Plasmids, Farm animals
