An Overview on Vancomycin Resistant Enterococcus faecalis

Abstract

There are over 15 species of the Enterococcus genus, with 80-90% of clinical isolates identified as E. faecalis. The aim of this work is to review the current information on Vancomycin-resistant Enterococcus faecalis. The study reviewed electronic documents and hard copies from public libraries of relevant literature relating to the biology, epidemiology, drug resistance mechanisms, treatment, and control of Enterococcus faecalis. The review revealed that Enterococcus faecalis, formerly known as Streptococcus faecalis, is a Gram-positive commensal bacterium that inhabits the gastrointestinal tracts of healthy humans and other mammals. However, it can cause life-threatening infections in humans, especially in the nosocomial environment, where there are naturally high levels of antibiotic resistance. Thus, Enterococci have proven to present a therapeutic challenge because of their resistance to many antimicrobial drugs, including cell-wall active agents; aminoglycosides, penicillin, ampicillin, and vancomycin. The Enterococci have the capacity to acquire a wide variety of antimicrobial resistance factors through plasmid transfer by conjugation, which presents serious problems in the management of patients with Enterococcal infections. In general, Enterococcal isolates with lowered susceptibility to vancomycin are categorized as vanA, vanB, and vanC, with vanA and vanB posing the greatest threat because they are the most resistant genes. E. faecalis is also resistant to teicoplanin. Enterococcal strains that are vancomycin-dependent have been found, but they are rare and less common than vancomycin-resistant strains (referred to as "vancomycin-resistant Enterococci" or "VRE"). The review identified that although VRE infections have the potential to become endemic, especially in very ill, debilitated patients who have been exposed to broad-spectrum antibiotics, and in the immunocompromised, Vancomycin continues to be the drug of choice for serious, life-threatening infections such as sepsis, pneumonia, and endocarditis.