Purpose: The purpose of the present study was to perform a molecular epidemiological survey by investigating the antibiotic resistance and the presence of known virulence factors in
Enterococcus faecium
isolates in Iran. The data collected from this study would allow us to control the spread and develop strategies for treatment of the enterococcal infections.
Materials and Methods: In this study, 156 vancomycin-sensitive
E. faecium (VSEF; 58) and vancomycin-resistant
E. faecium (VREF; 98) samples were isolated from clinical specimen and sewage treatment plants (STPs). These isolates were screened for the presence of genes encoding for aggregation substance (
asa1), cytolysin (
cyl), enterococcal surface protein (
esp), gelatinase (
gelE) and hyaluronidase (
hyl) by polymerase chain reaction (PCR).
Results: Although significantly different, the results showed the presence of
hyl and
esp genes in both clinical (41 and 75%, respectively) and sewage (3.2 and 41%, respectively) isolates. Sensitivity of all isolates to seven antibiotics was examined. The results of the clinical isolates showed that the majority of
esp positive isolates were also resistant to vancomycin, ciprofloxacin and erythromycin. Furthermore,
cyl,
gelE and
asa1 were not found in either clinical or STP isolates. Finally, we determined the distinct types of isolates using Pulse Field Gel Electrophoresis (PFGE), which confirmed that most of the isolates were clonally unrelated.
Conclusion: Our results demonstrated that higher number of the clinical
E.
faecium isolates carried virulence genes than the isolates from STP. Finally, the lack of the genes in clinical and STP isolates confirmed that these genes do not transfer horizontally.
