Survival of vancomycin-resistant and vancomycin-susceptible enterococci on dry surfaces

We compared the abilities of Enterococcus faecium strains (three vancomycin-resistant enterococci [VRE] and five vancomycin-susceptible enterococci [VSE]) and Enterococcus faecalis strains (one VRE and 10 VSE) to survive under dry conditions. Bacterial suspensions of the strains were inoculated onto polyvinyl chloride and stored under defined conditions for up to 16 weeks. All strains survived for at least 1 week, and two strains survived for 4 months. A statistical model was used to distribute the 19 resulting survival curves between two types of survival curves. The type of survival curve was not associated with the species (E. faecalis versus E. faecium), the source of isolation (patient versus environment), or the susceptibility to vancomycin (VRE versus VSE). Resistance to dry conditions may promote the transmissibility of a strain, but VRE have no advantages over VSE with respect to their ability to survive under dry conditions.