Clonal spread and horizontal transfer in the spread of vancomycin resistance genes were investigated. Multiplex PCR, pulsed-field gel electrophoresis (PFGE), hybridization of enterococcal plasmids with the vanA and vanB probes, and sequencing of a fragment of vanB were used in the analysis. Before May 1996, 12 vancomycin-resistant Enterococcus faecium (VRE) isolates were found in Finland. Between May 1996 and October 1997, 156 VRE isolates were found in the Helsinki area. Between December 1997 and April 1998, fecal samples from 359 patients were cultured for VRE. One new case of colonization with VRE was found. During the outbreak period, 88% (137 of 155) of the VRE isolates belonged to two strains (VRE types I and II), as determined by PFGE. Each VRE type I isolate possessed vanB, and five isolates also had vanA. Of the 34 VRE type II isolates, 27 possessed vanA and 7 possessed vanB. Fifteen of 21 (71%) ampicillin-resistant, vancomycinsensitive E . faecium (VSE) isolates found during and after the outbreak period in one ward were also of type II. Two VSE type II isolates were found in the hospital before the outbreak in 1995. By PFGE, the three groups (vanA, vanB, or no van gene) of type II shared the same band differences with the main type of VRE type II with vanA. None of the differences was specific to or determinative for any of the groups. Our material suggests that vanA and vanB incorporate into an endemic ampicillin-resistant VSE strain.

The objective of this study was to characterize the overgrowth and susceptibility of Enterococcus faecium, compared with that of other enterococci, in the feces of patients with hematologic malignancy. During a 52-week period, surveillance samples of feces were cultured weekly. Three hundred thirty-three samples were obtained from 92 patients. E. faecium outnumbered other enterococci in 170 (44%) of the samples, while the opposite was true in 119 (31%) of the samples. Fecal overgrowth of E. faecium (> or = 9.0 log10 cfu/g) was found in 62 samples (16%), while overgrowth of other enterococci was documented in 20 samples (5%) (P < .001). Treatment with third-generation cephalosporins preceded the overgrowth of E. faecium in 93% of the patients. Resistance of E. faecium isolates to ampicillin, high-level gentamicin, and vancomycin was detected in 41%, 4%, and 2% of the patients, respectively. There were 6 patients with enterococcal bacteremia (due to E. faecium in 5 and Enterococcus faecalis in 1) during the study period. The high prevalence of resistance to ampicillin and imipenem rendered few (if any) intravenous antibiotics able to prevent fecal overgrowth of E. faecium.

The purpose of our study was to determine retrospectively the risk factors for the acquisition of Enterococcus faecalis vs E. faecium bacteraemia, as well as the clinical outcomes of these patients. 62 patients with Enterococcus faecalis bacteraemia were compared to 31 patients with E. faecium bacteraemia. Haematologic malignancies, neutropenia, high-risk source and previous use of aminoglycosides, carbapenems, cephalosporins and clindamycin were significantly associated with E. faecium bacteraemia. Instead, urinary catheterization was found to be related to Enterococcus faecalis bacteraemia. The mortality rates within 7 d and 30 d were 13% and 27%, respectively, in patients with E. faecalis bacteraemia and 6% and 29%, respectively, in patients with E. faecium bacteraemia. There was no difference in mortality between E. faecalis and E. faecium bacteraemia, nor was there a difference in seriousness of disease at the time of bacteraemia. In the subgroups of patients with monomicrobial or clinically significant E. faecalis vs E. faecium bacteraemia, the mortality rates were similar to the results of all subjects. Our results do not support the theory that E. faecium would be a more virulent organism than E. faecalis.

The emergence of hospital acquired infections with bacteria resistant to antimicrobials such as vancomycin resistant enterococci (VRE) has become a worldwide concern. In hospitals in the United States, VRE have spread quickly and currently account for eve