Presence of virulence factors in Enterococcus faecalis and Enterococcus faecium susceptible and resistant to vancomycin

Despite the increasing importance of Enterococcus asopportunistic pathogens, their virulence factors are still poorly understood.This study determines the frequency of virulence factors in clinical andcommensal Enterococcus isolates from inpatients in PortoAlegre, Brazil. Fifty Enterococcus isolates were analysed andthe presence of the gelE, asa1 andesp genes was determined. Gelatinase activity and biofilmformation were also tested. The clonal relationships among the isolates wereevaluated using pulsed-field gel electrophoresis. The asa1,gelE and esp genes were identified in 38%,60% and 76% of all isolates, respectively. The first two genes were moreprevalent in Enterococcus faecalis than in Enterococcusfaecium, as was biofilm formation, which was associated withgelE and asa1 genes, but not with theesp gene. The presence of gelE and theactivity of gelatinase were not fully concordant. No relationship was observedamong any virulence factors and specific subclones of E.faecalis or E. faecium resistant to vancomycin. Inconclusion, E. faecalis and E. faeciumisolates showed significantly different patterns of virulence determinants.Neither the source of isolation nor the clonal relationship or vancomycinresistance influenced their distribution.