Comparative meta-analysis of prevalence and molecular features of high-priority Enterococcus faecium and E. faecalis from the guts of food-producing and wild birds

Abstract

Birds harbour Enterococcus faecium and Enterococcus faecalis as gut commensals but could acquire and transmit high-priority strains. Following the PRISMA guidelines, eligible studies that reported the antimicrobial resistance (AMR) profiles of E. faecium and E. faecalis from gut samples of food-producing (FPBs) and wild birds (WBs) published from 2005-2024 were screened from major bibliographic databases. Random-effect models were used to determine the pooled prevalences (PPs) of vancomycin (VAN^R), ampicillin (AMP^R), and linezolid (LZD^R) resistant E. faecium and E. faecalis from non-duplicated gut samples of FPBs and WBs. Of the 36 eligible studies, the overall PP of VAN^R-E. faecium and VAN^R-E. faecalis were 1.8% and 0.7%, respectively. AMP^R-E. faecium and AMP^R-E. faecalis were 1.6% and 0.6%, respectively. LZD^R-E. faecium and LZD^R-E. faecalis were 1% and 0.8%, respectively. Subgroup analyses revealed significant temporal variations in the PPs of VAN^R-E. faecium (P < 0.05). FPBs had significantly higher PPs of VAN^R, AMP^R and LZD^R E. faecium and E. faecalis than WBs (P < 0.05). Healthcare-associated vanA-carrying E. faecium lineages from WBs (ST16, ST17, ST18, and ST412) and optrA-carrying E. faecalis lineages (ST32, ST59, ST330) from FPBs were identified. In FPBs, Egypt had the highest PP of VAN^R-E. faecium (11.9%) and LZD^R-E. faecalis (2.8%). Conversely, the USA had the highest PP of VAN^R-E. faecium in WBs (2.4%). A higher frequency of vancomycin- than linezolid-resistant strains exists, and VAN^R-E. faecium are disproportionately distributed based on bird species, year of study, and country, indicating varied selection pressure. Significantly higher prevalence of VAN^R-E. faecium than VAN^R-E. faecalis was found, highlighting the higher capacity of E. faecium to acquire ampicillin and vancomycin resistance in birds.RESEARCH HIGHLIGHTS Vancomycin, ampicillin, and linezolid resistance in E. faecium and E. faecalis are considered high-priority public health concerns.This is a meta-analysis of high-priority E. faecium and E. faecalis from gut samples of birds.Food-producing birds had significantly higher frequency of priority E. faecium and E. faecalis than wild birds.Vancomycin resistance in E. faecium and E. faecalis exists more frequently than linezolid resistance.E. faecium has a higher capacity to acquire ampicillin and vancomycin resistance than E. faecalis.Genetically related human-adapted vancomycin- and linezolid-resistant strains were identified in food-producing and wild birds.

Keywords: Vancomycin-resistant E. faecium; food-producing birds; high-risk enterococci; linezolid-resistant E. faecalis; meta-analysis; wild birds.