Influência de antimicrobianos na expressão de genes de virulência associados à produção de biofilme em Enterococcus faecalis

Abstract

Biofilms have been considered a key factor in the pathogenesis of enterococcal infections. The current study aimed to investigate the impact of antimicrobials in both, biofilm formation and expression of virulence genes in penicillin-resistant, ampicillin-susceptible E. faecalis (PRASEF) and penicillin- and ampicillin-susceptible E. faecalis (PSASEF) isolates. Twenty PRASEF and 21 PSASEF clinical isolates were used to investigate the effect of sub-minimal inhibitory concentrations (sub-MIC) of antimicrobials on biofilm formation and 10 isolates were submitted to the RT-qPCR assay to detect gene expression of efaA, asa1, esp and ace. All PSASEF and PRASEF isolates showed capacity to produce biofilm. Gentamicin did not have any significant effect on biofilm formation but increased the ace expression (+136%). Ampicillin and penicillin decreased the production of biofilm but did not significantly affect the expression of the virulence genes investigated. The expression of ace (+108%) and asa1 (+120%) were higher among PSASEF isolates. In conclusion, the findings of this study showed that the biofilm formation ability were similar among PRASEF and PSASEF isolates although the expression pattern of ace and asa1 genes was higher among PSASEF isolates and the expression pattern could be changed by exposure to antimicrobials. In addition, the ability of biofilm formation was not influenced by exposure to sub-MIC of gentamicin in contrast to ampicillin and penicillin.