C A Review of Genes Related to Biofilm Formation in Enterococcus

Background: Enterococcus faecium is of great importance among Enterococcus species due to its antibiotic resistance and biofilm formation. The ability to form a biofilm on living surfaces is considered one of the most important pathogenic factors in this bacterium. E. faecium is involved in endocarditis, urinary tract infection, dental root infections, and eye infections by forming biofilms. Various factors, including the antibiotic resistance of E. faecium and the expression of genes involved in pathogenicity and biofilm formation, are involved in the stability of this bacterium in different conditions and the spread of infection. Objectives: Considering the special importance of E. faecium in biofilm production, the aim of this study was to review the presence and role of genes effective in biofilm formation in E. faecium bacteria. Materials and Methods: PubMed, Embase, and Web of Science databases were searched using the keywords genes , biofilm formation , Enterococcus , and quorum sensing . Studies that investigated the role of genes in the occurrence of biofilm in E. faecium were also included in the study. Results: Biofilm formation in enterococci involves a complex interaction of genes and virulence factors, including gelatinase, cytolysin, secreted antigen A, pili, and MSCRAMMs (microbial surface components recognizing adhesive matrix molecules). Polysaccharides also play a role in enterococcal biofilm formation. They are secreted in the form of capsules or exopolysaccharides. The genes involved in the production of polysaccharides include Sal, atn, epa, DltA, ebpABC, and bee. These genes increase the production of biofilm and attachment to the extracellular matrix. Quorum sensing, a process of intercellular communication, mediated by peptide pheromones such as Cob, Ccf, and Cpd, by targeting gene expression and regulation, plays an important role in biofilm development. The Fsr locus contains fsrA, fsrB, and fsrC genes. Furthermore, the regulation of extracellular DNA (eDNA) release has emerged as an essential component in biofilm formation. Conclusion: Biofilm formation in E. faecium is dependent on a large number of factors, including multiple genetic factors, a series of environmental conditions, and also a series of environmental signals, many of which need to be identified and researched. A complete understanding of the role of genetic and environmental factors involved in biofilm development may lead to the improvement and development of strategies for biofilm control in enterococci.