Co-infection or co-colonization with vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus in a network of community hospitals.

To the Editor: The isolation of both methicillinresistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE) from individual patients is ominous in light of the documented transfer of the vanA gene encoding vancomycin resistance from VRE to S. aureus. The article by Warren et al. in the February issue of Infection Control and Hospital Epidemiology described the epidemiology of this important phenomenon of co-colonization or co-infection with MRSA and VRE. Using universal surveillance for VRE colonization and clinical cultures for MRSA, the authors showed that at least 9.5% of patients in a medical intensive care unit (ICU) of Barnes-Jewish Hospital, an urban 1,400-bed, tertiary-care hospital, were co-colonized or co-infected with MRSA and VRE. This disturbingly high frequency is almost certainly replicated in ICUs of tertiarycare hospitals throughout the United States.