Alarming spread of vancomycin resistant enterococci in Sweden since 2007

Area of Science:

• Infectious Diseases
• Microbiology
• Public Health

Background:

• Mandatory reporting in Sweden revealed a dramatic increase in vancomycin-resistant enterococci (VRE) cases during 2007-2008.
• This surge followed widespread dissemination of VRE, originating in Stockholm hospitals and spreading to other healthcare facilities.

Purpose of the Study:

• To analyze the epidemiology and characteristics of a significant VRE outbreak in Sweden.
• To evaluate the impact of implemented control measures on VRE dissemination.

Main Methods:

• Analysis of mandatory VRE case reports from July 2007 to February 2009.
• Characterization of isolates using pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing.
• Review of implemented infection control countermeasures.

Main Results:

• A total of 760 VRE cases were reported, a substantial increase compared to previous years.
• Healthcare-acquired Enterococcus faecium with vanB resistance (E. faecium vanB) was dominant (n=634), with clonal dissemination indicated by PFGE.
• Median vancomycin MIC was 32 mg/L; teicoplanin MIC was 0.12 mg/L.

Conclusions:

• The VRE outbreak was primarily driven by clonal spread of E. faecium vanB within Swedish healthcare settings.
• Implemented countermeasures successfully decreased the dissemination rate, though new infections continued to occur.
• Vigilance and continued infection control practices are crucial for managing VRE spread.