Occurrence of virulence-associated genes in clinical Enterococcus faecalis strains isolated in Londrina, Brazil

Abstract

Epidemiological studies have reinforced the importance of Enterococcus faecalis in causing serious infections, and to date, our understanding of how certain virulence factors are involved in the pathogenesis of enterococcal infections is still limited. The aim of the present study was to examine the occurrence of known virulence determinants in a group of E. faecalis strains isolated from different clinical sources in Brazil. A total of 95 E. faecalis strains were investigated for the presence of nine virulence genes including aggA, cylA, cylB, cylM, eep, efaA, enlA, esp and gelE by using PCR. The data showed a relatively wide distribution of the virulence genes among the investigated strains. The clinical strains carried at least one and concomitantly up to as many as eight virulence markers, with two or three being the most common pattern. Most of the strains carried efaA (58.9 %), eep (58.9 %) and esp (57.9 %) genes, whereas the remaining virulence markers were detected in variable percentages ranging from 9.5 to 45 %. Simultaneous presence of virulence markers was observed among clinical strains regardless of their sources. In this study, the efaA + esp + gelE + profile was the virulence genotype most frequently detected among E. faecalis strains. Finally, there was no significant association between virulence markers and clinical sources.