Molecular characterization of EF3314 surface anchor protein and prediction of epitope peptides in Enterococcus faecalis

A BSTRACT Objectives: Enterococcus faecalis is a facultative anaerobe, and in recent years, it has emerged as an important cause of nosocomial infections. Among various virulent factors, a new cell wall-specific, surface anchor protein EF3314 contributes to the pathogenesis of the organism in the establishment of many recalcitrant infections. The aim of this study is thus to analyze the frequency of EF3314 by molecular methods and to predict the immune-dominant peptides from the EF3314 using an immune-informatics approach. Materials and Methods: Clinical strains of E. faecalis were characterized from the dental caries specimens, assessed for its multidrug resistance (MDR) property based on CLSI guidelines, and the presence of EF3314 by polymerase chain reaction (PCR). The protein sequence of the EF3314 protein from E. faecalis was further retrieved from UniProt and was subjected to assess allergenicity, secondary structure, antigenicity, stability predictions, physico-chemical analysis, and identification of major histocompatibility complex (MHC) Class II binders. Final selection of B-cell epitopes was done with the Immune Epitope Database B-cell epitope tool. Results: From the caries specimens, E. faecalis was isolated from 5 specimens (25%), with 3 MDR strains and 2 strains positive for EF3314 gene. Based on the combinatorial scores, the epitope peptide MILVFIVYF was suggested to be a promising vaccine candidate from EF3314 of E. faecalis . Conclusion: The study warrants the need for the periodical surveillance of the virulent and resistant traits of E. faecalis in dental health care settings. For the targeted therapeutic approach, immune-informatics is a suitable approach to design novel vaccine epitopes to treat infections caused by E. faecalis . However, the predicted epitope peptide needs further preclinical trials for its immunological response and memory against E. faecalis .