Enterococcus faecium Virulence Factors and Biofilm Components: Synthesis, Structure, Function, and Inhibitors

Enterococcus faecium, a Gram-positive bacterium belonging to the family Enterococcaceae is known for its clinical significance due to its ability to cause infection, especially in healthcare. It exists in anaerobic conditions and is frequently found in the human intestinal tract. This strain is extremely resistant to aminoglycosides, penicillin, and vancomycin as it possesses innate and acquired antibiotic resistance. This chapter provides an overview of virulence factors and biofilm formation that enhance the organism’s pathogenicity. The virulence factors are mainly categorized into secreted factors and cell surface factors. The secreted virulence factors and their genes concerned include cytolysin (clyA, clyB, clyM), secreted antigen A (sagA), gelatinase (efaAfs, efaAfm), and Glucosyl hydrolase (hylEfm). The cell surface virulence factors include Aggregation Substances (asp1, asc10 (prgB), asa1), MSCRAMMs (ace, acm, scm), Pili (piliA, piliB, piliF), Esp (espfs, espfm), which cause damage to the host cell and help in the formation of biofilm. Biofilm formation involves coordinated action of various components, enzymes, and genetic pathways. Polysaccharides such as exopolysaccharides are synthesized and secreted by the bacterium; lipids & proteins stabilize the structure of biofilm; while nucleic acid (eDNA) gives the structural integrity to the matrix and exchange of genetic material. Management and control of E. faecium infection includes the development of inhibitors targeting biofilm formation and virulence factors. Potential inhibitors include a quorum sensing system that interferes with bacterial communication, an electrochemical method for the degradation of biofilm, degradation of the EPS matrix of biofilm, external membrane structure, and enzyme-mediated biofilm control that degrades the biofilm. Additionally, the discovery of new antibiotics and therapeutic strategies remains essential for managing E. faecium infection. Understanding the virulence factors, biofilm formation, and potential inhibitors of E. faecium is critical for developing effective treatments and preventing the spread of this pathogen in healthcare settings.