Molecular typing of Enterococcus faecalis strains resistant to high levels of gentamicin and isolated in Romania

Sixteen Enterococcus faecalis strains resistant to high levels of gentamicin, 15 of which were isolated in the same year in a Romanian hospital, harboured conjugative gentamicin resistance (Gm(r)) plasmids ranging from 55 to 85 kilobases. On the basis of restriction enzyme and DNA-DNA hybridization profiles of these plasmids, as well as of chromosomal SmaI macrorestriction and Tn916 hybridization patterns, clonal relationship was established for seven strains whereas the other strains were considered to be independent. Nine and seven of the Gm(r) plasmids carried Tn4001-like and Tn4001-truncated structures, respectively; the latter structures were truncated in the right-hand flanking extremity of the element.