# Dissemination of Enterococcuscal Genetic Lineages: A One Health Perspective
## 4 Enterococcal Genetic Traits: Dissemination in the One Health Continuum
### Dissemination of Genetic Traits across One Health Sectors
Regarding the dissemination of ARGs and virulence determinants, some authors [111; 119] have found evidence of clinical antimicrobial-resistant _Enterococcus_ disseminated across the food chain. Indeed, meat was indicated as a transmission pathway of _E. ficecium_ and ARGs from animals to humans. [PERSON] et al. [142] performed a genomic survey of the presence and ARG relatedness of VREfm isolates from livestock farms, retail meat, WWTPs, and bloodstream infections in the United Kingdom and Ireland. Although the authors [120] observed a decrease in VREfm prevalence (between 2003 and 2018), VREfm was isolated in retail meat and was considered ubiquitous in WWTPs. Furthermore, the majority of human- and livestock-related isolates were genetically distinct, and limited sharing of acquired ARGs was observed between healthcare-associated enterococci and livestock. However, [PERSON] et al. [119] demonstrated that human clinical ampicillin- and multidrug-resistant _E. ficecium_ clones disseminated in Tunisia were not only genetically identical to clinical enterococci found in other countries and continents, but also identical to strains isolated from animal sources and food in this country. Regarding the spread of enterococcal-related resistance and virulence within food samples, [PERSON] et al. [111] demonstrated that _E. ficecium_ belonging to CC17 is present in poultry, veal, and rabbit. More recently, [PERSON] et al. [143] investigated the presence of _poxtA_- and _optrA_-carrying linezolid-resistant _E. ficecalis_ in food-producing animals and retail meat in Tunisia. OptrA is a gene responsible for acquired linezolid resistance and has been rapidly spreading among enterococci of various origins. The authors [143] also highlighted that enterococci recovered from food-producing animals and retail meat in Tunisia carried a plasmid fragment similar to the one found in enterococcal human and swine samples from China. Additionally, some _E. ficecium_ from animals and _E. ficecalis_ from the community displayed genetic profiles related with healthcare-associated epidemic strains belonging to clade A1, specifically ST17, ST18, and ST78. However, the community's _E. ficecalis_ was mostly associated with healthcare sequence types, such as ST6, ST40, and ST116. Supporting the results by [PERSON] et al. [143], [PERSON] et al. [144] recently isolated enterococci strains from pig carcasses and environmental samples in duck slaughterhouses in China. Approximately 11% of the isolates were resistant to linezolid, with a portion being _poxtA_-positive (1.7%) and _optrA_-positive (16.2%), demonstrating the widespread existence of oxazolidone resistance genes through the food chain to humans [144]. The detection of the same linezolid-resistant enterococci in both food-producing animals and retail meat suggests a potential role of the food chain in the dissemination of this trait, even without selective pressure. Furthermore, the same study also identified the presence of virulence genes typically found in clinical _E. ficecium_ from clade A1, including _sgrA_, _echA_, _esp_, and _acm_. These findings indicate the putative pathogenicity of those enterococcal isolates and highlight the possibility of transmission to humans through food [143]. Additionally, another research group performed a molecular characterization of high-level gentamicin-resistant (HLGR) _E. faecalis_ harboring aminoglycos-modifying enzymes and virulence genes in retail poultry means from Korea [100]. The authors [100] described ST82 as a foodborne HLGR _E. ficecalis_ clone, with a track record of outbreaks in poultry in other countries. Although enterococci can persist and survive in both fresh and marine water, there is still a lack of consensus regarding their ability to grow and multiply in these environments, due to the scarcity of nutrients [2; 145]. Despite this fact, enterococci can be isolated from a panoply of environmental settings with variable availability of nutrients, such as soil, freshwater, beaches [146], and wastewater treatment plants (WWTPs) [147; 148].