Vancomycin-resistant Enterococcus spp. in marine environments from the West Coast of the USA

The aim of the study was to determine if vancomycin-resistant Enterococcus spp. [VRE] carrying vanA and/or vanB genes were present in public marine beaches and a fishing pier [2001-2003, 2008] from Washington and California [2008]. PCR assays for the vanA and/or vanB genes with verification by DNA-DNA hybridization of the PCR products were used. Positive isolates were speciated using the BD BBL Crystal (TM) Identification and/or by sequencing the 16S ribosomal region. Eighteen (8%) of 227 isolates including Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus/gallinarum and a Staphylococcus epidermidis carrying vanA and/or vanB genes, from four of six Washington and one of two California sites, were identified. Selected VRE and the S. epidermidis were able to transfer their van genes to an E. faecalis recipient at frequencies ranging from 1.9 x 10(-6) to 6.7 x 10(-9). Vancomycin-resistant Enterococcus spp. was isolated from five of the seven sites suggesting that other North America public beaches could be the reservoirs for VRE and should be assessed. This is the first report of isolation and characterization of VRE strains (and a vanB Staphylococcus sp.) from North American environmental sources suggesting that public beaches may be a reservoir for possible transmission of VRE to beach visitors.