Epidemiological analysis of vancomycin-resistant enterococci in a large tertiary-care hospital in Northern Italy

The epidemiology of vancomycin-resistant enterococci (VRE) was studied in a large tertiary-care hospital in northern Italy from February 1993 to December 1999. Sixteen cases of bacteraemic and 17 cases of nonbacteraemic active infections caused by VRE were recorded. Fifteen of the bacteraemic and four of the nonbacteraemic infections occurred in patients in the haematology department, while the remainder were registered in other departments of the same hospital. Active surveillance for the presence of VRE in stools led to identification of 51 noninfected carriers over the 1994-1999 period; of these, 32 were haematology patients and the remainder were patients admitted to other departments. All VRE isolates carried the vanA gene. Forty-one Enterococcus faecium isolates and eight Enterococcus faecalis isolates collected in the 1993-1996 period were typed by pulsed-field gel electrophoresis. Twenty-nine isolates of Enterococcus faecium shared either indistinguishable or strictly or possibly related patterns. Of these, 26 were isolated from patients in the haematology department. This is believed to be the first study on the epidemiology of VRE carried out in a large hospital in Italy over a period of several consecutive years. It reports an increase in VRE due to the epidemic spread of genetically related strains and sporadic infections or colonisation by unrelated VRE. It also documents the success of surveillance and of the measures adopted for preventing the spread of VRE in patients at risk.