Acquisition and duration of vancomycin-resistant enterococcal carriage in relation to strain type.

In May 2000, the first outbreak of vancomycin-resistant Enterococcus faecium (VREF) was detected in the University Medical Center Utrecht in the nephrology ward. The question arose why some VREF strains spread among hospitalized patients, whereas other strains do not. Thirty patients who were found to be colonized with VREF between May and November 2000 were included in the study. Molecular typing confirmed that 19 of them carried an identical epidemic strain which harbored the esp gene while 11 were colonized by nonepidemic strains that were all esp negative. Acquisition of the outbreak strain was significantly associated with diabetes mellitus, renal transplantation, and extensive use of antibiotics, especially cephalosporins, in the 2-month period before the first isolation of VREF. To establish the duration of colonization, prospective surveillance of VREF carriage for a 6-month period starting from the first isolation of VREF was realized for 20 patients. After 6 months, VREF was still recovered from 60% of carriers of the outbreak strain versus 20% of carriers of nonepidemic strains (P < 0.01). However, antibiotic use during the follow-up period was significantly higher by carriers of the outbreak strain than by carriers of nonepidemic strains. The fact that the outbreak strain was recovered for a longer period of time than nonepidemic strains may facilitate dissemination of the strain. The results support a careful restrictive antibiotic policy for wards at risk for spread of VREF and implementation of isolation precautions for patients who are colonized with esp-positive outbreak strains.

[Epidemic of methicillin-resistant Staphylococcus aureus due to the transfer of 2 Dutch burn patients from a hospital outside of the Netherlands; who suffers the consequences?]. / Epidemie van meticillineresistente Staphylococcus aureus door overname uit een buitenlands ziekenhuis van 2 Nederlandse brandwondpatiënten; wie draagt de gevolgen?

Two burns patients who were transferred to the Central Military Hospital Utrecht from a foreign hospital, were found to be colonised with MRSA. During their 5-week hospitalisation, 21 healthcare workers and one patient became colonised with the same MRSA strain, despite isolation precautions. The department was closed for 29 days; 96 admissions were cancelled and 1411 screening cultures for MRSA were performed. Colonised healthcare workers were temporarily unable to work and additional costs were incurred for disposables and cleaning procedures. The resultant bill for this outbreak was approximately [symbol: see text] 122,500. MRSA outbreaks occur in hospitals with some degree of regularity, but the strong dispersal during this epidemic was exceptional. The transfer of possible MRSA-colonised patients from hospitals outside of the Netherlands sometimes faces opposition due to the considerable demands it makes on a hospital's personnel, organisation and finances. If this were to be compensated, then the currently successful Dutch MRSA policy could be coupled with a willingness to accept patients from hospitals outside of the Netherlands.

Outbreak of a susceptible strain of Acinetobacter species 13 (sensu Tjernberg and Ursing) in an adult neurosurgical intensive care unit.

Between December 1999 and June 2000, an outbreak caused by Acinetobacter emerged on the neurosurgical intensive care unit of our hospital. It was shown using automated ribotyping using Eco RI and pulsed-field gel electrophoresis that the outbreak was caused by spread of a single strain, which was identified by ribotyping and amplified ribosomal DNA restriction analysis as Acinetobacter DNA group 13TU (sensu Tjernberg and Ursing). The outbreak strain, which showed no antibiotic resistance, was identified in 23 patients, five of whom developed an infection. The organism was also isolated from various environmental sites. Cross-transmission among patients continued despite contact isolation of colonized patients and reinforcement of basic disinfection procedures. Eventually, after implementation of additional stringent measures such as cohorting of positive patients and daily disinfection of the floor, the outbreak was brought under control. This study demonstrates that apart from Acinetobacter baumanii, Acinetobacter 13TU strains, even when they are fully susceptible, may cause outbreaks that are difficult to control. Correct identification to the species level of Acinetobacter by genotypic methods is necessary to get insight in the importance of the different Acinetobacter genomic species in hospital epidemiology.