vanA-mediated vancomycin-resistant Enterococcus spp. in sewage.

Three high-level vancomycin-resistant Enterococcus strains (two Enterococcus faecium and one Enterococcus durans) were recovered from three of eight sewage samples taken from the general sewage collector at Logroño (Northern Spain). The strains were present in the sewage samples at estimated concentrations of ten resistant bacteria/mL, corresponding to about 0.4% of the enterococcal population. The VanA protein was detected in each strain by immunoblotting of membrane extracts of the vancomycin-induced cells, and the vanA gene was demonstrated in the wild strains and their transconjugants by DNA-DNA hybridization. This is the first, confirmed report of vanA mediated vancomycin resistance in E. durans.