HETEROGENEITY OF RIBOSOMAL-RNA GENE RESTRICTION PATTERNS OF MULTIRESISTANT SEROTYPE 6B STREPTOCOCCUS-PNEUMONIAE STRAINS

Three multiresistant serotype 6B Streptococcus pneumoniae strains were isolated from the middle ear fluids of children undergoing tympanosto my in Atlanta. Because multiresistant 6B pneumococci have been reporte d to spread from a single clone, the three isolates were compared with 13 other multiresistant 6B pneumococci by hybridization of endonuclea se-restricted DNA fragments with a digoxigenin-labeled cDNA probe comp lementary to 16 and 23S rRNAs (ribotyping). The ear isolates were hete rogeneous, whereas six of the other pneumococcal isolates were alike, indicating a need for additional studies to determine the possibility of clonal spread.