Surveillance of drug resistance and drug resistance genes in Enterococcus spp. from migratory birds in Nansha Wetland Park, Guangzhou, China.

To investigate the antibiotic resistance profiles and predominant tetracycline (TET) resistance genes in Enterococcus faecalis isolated from migratory birds, we collected 393 fecal samples from migratory birds at Guangzhou Nansha Wetland Park between January and December 2019.The samples were processed for bacterial isolation, culture, and identification, 79 samples were culture-positive for Enterococcus, the sample positivity rate was 20.10% (79/393), which included Enterococcus faecium (28 strains,35.44%) and Enterococcus faecalis (29 strains,36.71%). To avoid bias caused by clonal strains from the same host, only one representative isolate per positive sample was included in subsequent analyses.followed by antimicrobial susceptibility testing, PCR amplification of vancomycin (VAN) and TET resistance genes, and subsequent sequencing.Of these isolates,69.62% exhibited resistance to at least one antibiotic; the highest rates of resistance were observed for tetracycline (54.43%),erythromycin (ERY) (48.10%),and high-level streptomycin (STR) (17.72%).Furthermore, multidrug resistance (MDR) was detected in 27.85% of the strains examined, including four vancomycin-resistant enterococci (VRE).Sequencing analysis revealed that among the isolates tested,29 strains harbored the tetM gene—accounting for approximately 7.38% of all samples collected.These findings indicate a significant prevalence of antibiotic and multidrug resistance among enterococci in migratory birds within Guangzhou, underscoring a potential risk for the dissemination of VRE.