Enterococcal vanB resistance locus in anaerobic bacteria in human faeces

While developing a rapid method to detect carriers of vancomycin-resistant enterococci (VRE), we found the vans gene by PCR in 13 of 50 human faecal s pecimens that did not contain culturable VRE. Passaging under antibiotic se lection allowed us to isolate two species of anaerobic bacteria that were v ans PCR positive, vancomycin resistant, and teicoplanin sensitive. Sequence analysis of the 16S rRNA genes showed that one isolate resembled Eggerthel la lenta (98% identity), and the other Clostridium Innocuum (92% identity). Southern hybridisation and nucleotide sequencing showed a vane locus homol ogous to that in VRE. We propose that vans resistance in enterococci might arise hom gene transfer in the human bowel.