Strict Infection Control Measures Helped Conquer VRE Outbreak

The incidence of vancomycin-resistant enterococci (VRE) remains sporadic in Switzerland. Researchers in Lausanne, Switzerland report an unprecedented VRE outbreak in a 900-bed tertiary care hospital and describe its molecular epidemiology. VRE was detected in clinical specimens by standard procedures. Carriage screening was performed by rectal swab. Swabs were inoculated into an enrichment broth and grown on chromogenic VRE agar. Isolates were typed by PFGE.

Senn, et al. report that in November 2010, a first case of VRE was detected in a urine culture. The investigation identified three secondary cases in roommates (asymptomatic carriage). A second clinical case was detected in January 2011. Four secondary cases were identified. Both index cases were previously hospitalized in the same regional hospital. All patients transferred from the regional hospital were screened for VRE. In addition, weekly screening was initiated in patients hospitalized in the epidemic ward.

In total, from November 2010 to March 2011, 31 VRE cases were identified: four in clinical specimens (two urine and two wound) and 27 in screening swabs. One patient presented a VRE bacteremia. Molecular analysis showed that all isolates except two had the same PFGE pattern. The 2 different strains had only a variation of one to two bands and were probably related to the outbreak. Infection control measures (contact isolation of carriers and roommates, quarantine of the epidemic ward and reinforcement of environment disinfection) were implemented.

The researchers emphasize that the VRE outbreak was controlled by implementation of strict infection control measures.

Reference: L Senn, C Petignat, G Prod'hom, G Greub, P Basset, DS Blanc and G Zanetti. Unprecedented nosocomial spread of vancomycin-resistant Enterococcus faecium in a tertiary-care hospital in Switzerland. Presentation at the International Conference on Prevention & Infection Control (ICPIC). BMC Proceedings 2011, 5(Suppl 6):P22doi:10.1186/1753-6561-5-S6-P22