Epidemiology and molecular typing of VRE bloodstream isolates in an Irish tertiary care hospital

Objectives: Ireland has the highest rate of vancomycin-resistant Enterococcus faecium (VREfm) isolated from blood of nosocomial patients in Europe, which rose from 33% (110/330) in 2007 to 45% (178/392) in 2012. No other European country had a VREfm rate from blood cultures of .25%. Ouraim was to elucidate the reasons for this significantly higher rate in Ireland. Methods: The epidemiology and molecular typing of VRE from bloodstream infections (BSIs) was examined in a tertiary care referral hospital and isolates were compared with those from other tertiary care referral centres in the region. Results:The mostcommon source of VRE BSIs wasintra-abdominal sepsis, followed byline-related infection and febrile neutropenia. Most of the isolates were positive for vanA; 52% (43/83) possessed the esp gene and 12% (10/83) possessed the hyl gene. Genotyping by SmaI macrorestriction analysis (PFGE) of isolates revealed clonal relatedness between bloodstream isolates and environmental isolates. VRE BSI isolates from two other tertiary care hospitals in the Dublin region showedrelatedness byPFGEanalysis. MLSTrevealed four STs (ST17, ST18, ST78 and ST203), all belonging to the clonal complex of hospital-associated strains. Conclusions: Irish VRE BSI isolates have virulence factor profiles as previously reported from Europe. Typing analysis shows the spread of individual clones within the hospital and between regional tertiary care hospitals. Apart from transmission of VRE within the hospital and transfer of colonized patients between Irish hospitals, no other explanation for the persistently high VREfm BSI rate in Ireland has been found.