Virulence determinants and pathogenicity in Enterococcus faecalis and E. faecium

Enterococci are Gram-positive bacteria that inhabit the gastrointestinal tract of many organisms, including humans. These bacteria can easily adapt to their surrounding environment, even under stress conditions that can be lethal to other microorganisms. Among the species described in this genus, faecalis and faecium stand out, considered one of the main causes of nosocomial infections due to their ability to adapt and resist in clinical environments. They are recognized as opportunistic pathogens that can cause a variety of serious infections, such as endocarditis, urinary tract infections, and bacteremia, especially in immunocompromised patients or those with invasive medical devices. Recently, it has been observed that Enterococcus presents an increase in resistance to antibiotics, heavy metals, as well as external environmental conditions such as heat and desiccation. This resistance has been directly related to the capacity to form biofilm, an organized microbial ecosystem that makes it almost impermeable and serves as a shield for the bacteria. In addition, biofilm has been linked to bacterial virulence due to the presence of virulence factors. Therefore, researchers are interested in conducting research on the correlation between biofilm formation, virulence factors and antimicrobial resistance, which is essential to understanding the pathogenesis of these infections and improving treatment strategies.