# 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
In fact, enterococci are known to be present in the gastrointestinal tract of most animals, and there is abundant evidence that drug-resistant strains can occur in companion, farm, or wild animals and be transmitted to humans, causing zoonotic infections [9; 115]. Moreover, the overuse of antimicrobials in both human and veterinary medicine has led to the rapid emergence and dissemination of resistant bacteria, which nowadays are resistant to most antimicrobials used in clinical practice [116]. Furthermore, the usage of several antimicrobial classes is shared between human and animal clinical practice, resulting in an overlap of resistant genes detected in both settings, thus compromising human and animal welfare [117; 118]. A recent report [119] observed identical antibiotic resistance to ampicillin, virulence patterns, and bacteriocin production within clusters of clinical, farm animal, and retail meat samples, which indicates the transference of enterococcal genetic traits between animals and animal-based foods. This transmission between humans and animals was also confirmed in a previous report [120], which evaluated the spread of antimicrobial-resistant enterococci between dogs and owners in three different households. The authors [120] identified _E. faecalis_ in all three settings with very similar resistance patterns and detected clonal spread between pets and the respective owners within each household, the animals' body parts, and shared domestic objects. Another study described a 100-fold higher proportion of enterococci, including multidrug-resistant (MDR) _E. faecalis_ and/or _E. ficetium_, in the fecal microbiota of dogs submitted to antimicrobial therapy after leaving an intensive care unit, in comparison to healthy canines [121]. In fact, dogs were proven to harbor _E. ficetium_ belonging to STs related to human clinical isolates or hospital outbreaks, for instance ST17 [122; 121]. Moreover, enterococcal contamination in medical-associated surfaces at small veterinary hospitals was described by [PERSON] et al. [123], who also found MDR _E. ficetium_ isolates. Regarding studies which applied MLST, a previous report [121] examined enterococcal antimicrobial resistance in a veterinary clinic and demonstrated that dogs from intensive care submitted to antibioticrapy harbored MDR-_Enterococcus_, namely  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Species**} & \multicolumn{4}{c}{**Clonal Linesages**} & \multirow{2}{*}{**Virulence**} & \multirow{2}{*}{**Antimicrobial**} & \multirow{2}{*}{**Source**} & \multirow{2}{*}{**Location**} & \multirow{2}{*}{**Ref. **} \\ \cline{2-2} \cline{5-8}  & \multirow{2}{*}{**Clonal Complex**} & & & & & & \\ \cline{3-8}  & & & & & & & \\ \hline \multirow{4}{*}{-} & \multirow{4}{*}{ST1753, ST1755} & \multirow{4}{*}{_cfaA_, _acm_} & _arc6-Ii_, _errB_, _msr_ & \multirow{4}{*}{Litter-amended soil} & \multirow{4}{*}{} & \multirow{4}{*}{} \\  & & & & & & & \\ \cline{1-1} \cline{5-8}  & & & & _c, tettttt_, _catO_ & & & & \\ \hline \multirow{4}{*}{-} & \multirow{4}{*}{ST133} & \multirow{4}{*}{ND} & \multirow{4}{*}{_ac60-Ii_, _atAv_, _cO_,  
belonging to the species _E. faecalis_ and _E. facecium_. In addition, dog food commercially available in Portugal was reported as a reservoir of antimicrobial resistance enterococci with clinical relevance [110]. All the above highlight the importance of habitat sharing as a risk factor for the spread of pathogenic microorganisms and associated genetic determinants. Accordingly, a study by [PERSON] et al. [124], focusing on human and mouse microbiota, concluded that resistance due to antimicrobial treatment may be long-lasting, meaning that resistant strains may remain for long periods after the treatment is finished. Hence, this over-time colonization may increase the risk of the zoonotic spread of multi-resistant bacterial strains [125; 126; 127]. Previous reports [106] have already demonstrated the dissemination of specific genetic lineages between animals and humans. For example, _E.