Lack of increased colonization with vancomycin-resistant enterococci during preferential use of vancomycin for treatment during an outbreak of healthcare-associated Clostridium difficile infection.

Objective: To assess whether use of oral vancomycin for treatment during an outbreak of Clostridium difficile infection (CDI) was associated with increased rates of colonization with vancomycin-resistant enterococci (VRE).

Design: A retrospective analysis of hospital databases.

Setting: The Jewish General Hospital in Montreal, Quebec, Canada.

Methods: We collected data regarding VRE colonization and CDI from November 1, 2000, through September 30, 2007, during which policies of preferential oral metronidazole or vancomycin treatment were implemented to control an outbreak of CDI. Four periods were considered: period 1, the preoutbreak period when metronidazole was used; period 2, the CDI outbreak period when metronidazole was used; period 3, the postoutbreak period when vancomycin was used; and period 4, the postoutbreak period when metronidazole was used.

Results: A total of 2,412 cases of CDI and 425 cases of VRE colonization were identified. The rate of CDI increased significantly during period 2 and decreased to preoutbreak levels during period 3. The rate of VRE also increased during period 2 and decreased during the first 18 months of period 3. A clonal outbreak of cases of VRE (VanA) colonization was observed toward the end of period 3 and into period 4. Excluding the period of the clonal outbreak, there was a strong correlation between the number of cases of CDI and VRE colonization (r=0.736; P=.001) and a negative association between VRE colonization and vancomycin use (r=-0.765; P=.04).

Conclusions: Increased vancomycin use was not associated with an increase in VRE colonization over a 2-year period. Restriction of vancomycin use during CDI outbreaks because of the fear of increasing VRE colonization may not be warranted.