Enterococcus faecalis an Emerging Microbial Menace in Dentistry-An Insight into the In-Silico Detection of Drug Resistant Genes and Its Protein Diversity

Abstract

Introduction: Antimicrobial drug resistance is evolving as a serious threat to mankind due to indiscriminate use of antibiotics and lack of awareness about the mechanisms involved in drug resistance. Enterococcus faecalis, a common pathogen of the oral cavity has gained drug resistance over a period of years, making treatments refractory and ineffective. Aim: To detect the antimicrobial resistance encoding genes of Enterococcus faecalis employing computational tools. Materials and Methods: Antibiotic resistance genes were detected by retrieving sixteen genome sequences of Enterococcus faecalis from NCBI database which were further analysed using ResFinder. PlasmidFinder identified resistance encoding plasmids from recruited genomes under study. Protein sequences of most common phenotypes were subjected to protein BLAST and non-duplicate isolates showing 95-100% identity were selected for multiple sequence alignment using MEGA v7.0. Additionally, reconstruction of phylogenetic tree was performed to ascertain the diversity of these proteins among different genus and species. Results: In silico analysis of genomes revealed that almost all the probed isolates exhibited resistance towards glycopeptides and macrolides. The genes lsa(A) were found in 100% of the isolates, followed by tet (M) and erm (B) exhibiting a frequency of 37.5% and 25% respectively. Apart from major antibiotics, the isolates also demonstrated resistance towards aminoglycoside, phenicol, tetracycline and trimethoprim class of antimicrobials. Conclusion: The present investigation has emphasised the novelty in the application of in-silico tools in the understanding of the antibiotic resistance profile explored by the dreadful endodontic pathogen viz., E. faecalis. Further, this approach will aid in the implementation of improved treatment strategies and will facilitate to combat the dissemination of resistant gene cassettes to other oral pathogens or commensals residing in the vicinity.

Keywords

• drug resistance
• glycopeptides
• macrolides
• phylogenetic analysis
• plasmids