Abstract

Background: Although amongst vancomycin resistant (VR) enterococci (VRE) isolated from patients of Transplantation Institute Enterococcus faecinum predominated, some isolates of Enterococcus faecalis still occurred. The aim of our work was to perform molecular analysis of VR-E. faecalis strains derived from different years.
Material/Methods: Strains of VR E. faecalis were defrosted, multiplied and their DNAs were examined for the presence of vanA, vanB, vanD or vanG genes by PCR. The species status of each strain was confirmed by demonstration of the presence of the ddl gene specific for E. faecalis. PFGE was performed on bacterial DNA digested with SmaI. Products of digestion were separated using CHEF-DR III (Bio-Rad) and the obtained patterns of bands were compared.
Results: In 2003-2006 12 strains VR E. faecalis from 8 patients were isolated.
Two patients had liver transplanted and six kidney. All examined strains harboured vanA gene. Among investigated strains, five displayed patterns very similar to each other, even though they were isolated in different years and from different patients (2 in 2003, 1 in 2004 and 2 in 2005). All 5 strains were susceptible to ampicillin and highly resistant to aminoglycosides (HLAR). The patterns of bands after PFGE in the case of strains from remaining three patients were unrelated.
Conclusions: The results suggested also that the single strain of VR-E. faecalis
was present for three years in closely related hospital wards. The strain disappeared in 2006 and 2007.