Stored urine as a reservoir of gentamicin-resistant bacteria and as a site of conjugative R-plasmid transfer.

For some years we have observed the dissemination of gentamicin-resistant strains of Enterobacteriaceae in our hospital and we have reported the spread of antibiotic resistance by plasmid transfer. Stored urine was suspected to be a reservoir for gentamicin-resistant enterobacteria and to be a means of dissemination of gentamicin resistance amongst different species. We now report an epidemiological analysis based on biotyping of isolates and R-plasmid typing, and show that dissemination of bacterial strains and R-plasmids was not associated with disposable urine reservoirs, but dissemination of strains and plasmids was observed when non-disposable urine bottles were used in the wards.