Virulence factors and antibiotic resistance in Enterococcus faecalis isolated from urine samples

Haemolysin, enterococcal surface protein (Esp), aggregation substance and gelatinase are some markers that have been proposed as possible enterococci virulence factors. The aim of this study was to detect the presence of haemolysin, gelatinase and enterococcal surface protein in enterococci isolated from urine and to determine their susceptibility to antimicrobial agents. A total of 50 strains of Enterococcus faecalis isolated from urine samples was examined. UTI agar (Oxoid) was used for the isolation and identification of the strains as Enterococcus spp. The differentiation of the species was done by the Vitek automated system (GPI-card). Haemolysin production was detected phenotypically on Columbia CNA agar as a zone of beta haemolysis around the streak. Production of gelatinase was determined as a clear halo around the colonies on tripticase soy agar supplemented with 1.5% skim milk. Esp was proved by detection of the esp gene using PCR after DNA extraction. Antibiotic sensitivity to ampicillin, ceftriaxone, vancomycin, nitrofurantoin and ciprofloxacin was examined by the agar diffusion method. In 16 Enterococcus faecalis strains (32%) all the virulence factors were present. Two factors were found in 19 (38%) strains and only one in 11 strains. There were only 4 strains without any virulence factor. Esp was the most frequently determined factor (in 38 isolates). All the strains were susceptible to vancomycin and nitrofurantoin; 12 isolates were resistant to ampicillin, 17 to ceftriaxone and 14 to ciprofloxacin. No relationship was found between virulence factors and resistance to an antibiotic.