STUDIES ON THE DISTRIBUTION OF HIGH-LEVEL GENTAMICIN-RESISTANT ENTEROCOCCUS-FAECALIS USING RIBOTYPING AND RESTRICTION ANALYSIS OF THE 16S-23S RIBOSOMAL-RNA INTERGENIC SPACER SEQUENCES

Twenty-five high-level gentamicin resistant (HLGR) Enterococcus faecal is strains were isolated from three different University laboratories in Italy, The resistant strains were variously distributed in the thre e centers with percentages of prevalence ranging from about 3% up to 1 4%, Almost all strains shared high-level resistance to streptomycin (2 3 out of 25), Ribotyping and restriction analysis of the 16S-23S rRNA intergenic spacer sequences were used to genetically differentiate the various strains and to study their spreading in the university hospit als serviced by the three laboratories. At least three ribotypes were identified, which showed a peculiar distribution in the various center s, Only the ribotype B was isolated from the University of Padua, In C agliari, most strains belonged to ribotype A (4/6), whereas in Genoa t here was an equal distribution of the ribotypes A and B, A clonal spre ading of some HLGR strains is suggested by these findings, The restric tion analysis of the 16S-23S rRNA intergenic-spacer sequences gave com parable results with classical ribotyping and, in addition, was quicke r and easier to perform than the latter.