Role of Enterococcus in spreading antimicrobial resistance genes and its public health significance

Enterococci are ubiquitous Gram-positive, non-spore-forming, catalase-negative, chemo-organotrophic facultative anaerobic bacteria recognized as a significant public health concern due to their role in disseminating antimicrobial resistance (AMR) genes and disease-causing ability. Often found in various environments, such as the intestines of humans and other monogastric animals, green plants, silage, milk, and soil, it also regularly coexists alongside insects, birds, and other wildlife. Apart from coagulase-negative Staphylococcus and Staphylococcus aureus, it is the second most frequent cause of nosocomial bacteremia. It is a common bacterium that is naturally resistant to various antibiotics and can also develop resistance through point mutations and gene transfer. Thus, this review aims to explore the possible way Enterococci resist antibiotics through intrinsic mechanisms like altered penicillin-binding proteins and efflux pumps and acquired mechanisms such as horizontal gene transfer of resistance genes, mutations, and biofilm formation, enabling their survival and clinical persistence and also provides an overview of Enterococci general characteristics and its health implications in both human and animals. This review highlights the pressing need for intense monitoring, strict infection control protocols, and the creation of innovative therapeutic approaches to lessen Enterococcus's impact on public health by combining data on its disease burden, epidemiology, and resistance mechanisms. A multidisciplinary strategy that integrates clinical care, microbiology, and public health initiatives is needed to address these issues.