Phenotypic and Genotypic differences in the expression of virulence factors in antimicrobial resistance of Enterococcus faecalis clinical strains

There is no information on investigations comparing phenotypic and genotypic differences in MDR and MDS E. faecalis strains in literature. The study included 70 clinical E. faecalis isolates from human origin. None of the isolates tested demonstrated any in vitro sensitive to vancomycin, with MIC values of all the strains for vancomycin of ≥23 μg/mL. High-level resistances to ampicillin and streptomycin were detected by the disc diffusion method in 77% and 80% of the isolates, respectively. The MDR E. faecalis strains which were investigated produced significantly amounts of extracellular material binding Congo red and gelatinase quantity in culture supernatants when compared with MDS strains. The capacity to produce lipase and DNase activity were not found in any of the isolates investigated. Cytolysin activity was detected in 70% of MDR E. faecalis strains, where in only 20% of MDS E. faecalis. MDR strains adhered to polystyrene to a more extent than MDS strains. The presence of virulence genes (esp, cylA, gelE and EF3314) were investigated by PCR. MDR E. faecalis strains showed more detection of these genes than MDS E. faecalis strains. The presence of these genes did not correlate completely with their phenotypic expression. In conclusion, the MDR E. faecalis strains have impaired virulence when compared to MDS strains.