The Virulence Associated fsr Quorum Sensing System Play Key Roles in Enterococcus Faecalis

Abstract

\n Enterococcus faecalis, a major nosocomial pathogen, has become a top leading cause of hospital-acquired infections including urinary tract infections, endocarditis and bacteremia. It is important to study the epidemiology and virulence characteristics of E. faecalis isolates in order to tailor infection prevention and antibiotic prescribing. In this study, comparative genomic analysis was conducted on 537 isolates from different human origins. The isolates from bloodstream and intra-abdominal lining had the largest and smallest average genome size respectively, while the isolates from open natural orifices (gastrointestinal tract, urinary tract, respiratory tract, wound and eye) had medium average genome size. The phylogenetic relationships were expounded that the strain isolation niche is uncorrelated with strain phylogeny. Six clonal complexes generally appeared in different isolation sources. Furthermore, genomic analysis revealed differences at the accessory genome, the functions of different genes mainly pointed to the virulence, drug resistance and metabolism of E. faecalis. Interestingly, fsr quorum sensing system genes affecting biofilm formation had a highest proportion in the blood-derived strains. This study showed the genomic characteristics of different human origins and suggested that fsr quorum-sensing system maybe a contributing factor of bacteremia due to E. faecalis infection.