Molecular epidemiology of vancomycin resistant enterococcus faecium infecting solid organs recipients in the transplantology and transplant surgery wards in 2005–2006

Background: Because of the significant increase of the number of vancomycin resistant enterococci (VRE), especially Enterococcus faecium isolated from patients of Institute of Transplantology, It seems necessary to investigate the molecular epidemiology of these strains.
Material/Methods: VRE (E. faecium) isolated from various specimens from patients of Institute of Transplantology from 01.01.2005 to 31.12.2006 were investigated. After initial identification strains recognized as VRE were frozen and stored in -70°C until further testing. The strains were examined in the PCR reaction for the presence of vanA, vanB, vanD and vanG genes as well as ddl gene, to confirm type of vancomycin resistance and correctness of identification. Confirmed VRE E. faecium strains were examined by the molecular method known as restriction fragments length polymorphism - pulsed field - gel electrophoresis (RLFP-PFGE). Only one isolate per one patient was analyzed.
Results: In the investigated two years period, 57 patients of Institute of Transplantology were infected with VRE. 26 of them were recipients of liver, 22 of kidney and remaining 9 were other surgery or nephrology patients. All VRE strains from 2005 and the most from 2006 possessed vanA gene, only 5 strains possessed the vanB determinant. The PFGE analysis revealed among strains possessing vanA determinant a large group of related strains and several small groups as well as unrelated strains. Strains possessing vanB determinant were unrelated.
Conclusions: The PFGE analysis enables the investigation of epidemiology of
VRE among patients after transplantations. Strains with similar patterns most
probably originated from the one source and it may suggest an outbreak.

Keywords: Molecular