Prevalence of Enterococcus spp. and the Whole-Genome Characteristics of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Free-Living Birds in Poland.

Enterococci as opportunistic bacteria are important for human health. Due to the prevalence and ease of acquisition and transfer of their genes, they are an excellent indicator of environmental contamination and the spread of antimicrobial resistance. The aim of the study was to assess the prevalence of spp. in wild birds in Poland, determination of antimicrobial susceptibility and WGS analysis of (.) and . For this purpose, 138 samples from various species of free-living birds were tested, with 66.7% positive results. Fourteen species were detected, with being the most common, followed by and . In antimicrobial susceptibility testing, 10.0% of and 50.0% of showed resistance to one antimicrobial agent, in addition the MDR phenotype which was found in one . The most common resistance phenotype included tetracycline and quinupristin/dalfopristin. The WGS analysis confirmed the significant advantage of the virulence gene diversity of strains over . In addition, plasmid replicons were found in 42.0% of and 80.0% of . The obtained results confirm free-living birds can be a reservoir of spp. with a considerable zoonotic potential.