DIFFERENTIATION OF RHODOCOCCUS SPECIES BY RIBOTYPING

The ribosomal RNA gene restriction patterns (ribotyping) was investiga ted with respect to the characterization of Rhodococcus species and X. rhodochrous strains. Chromosomal DNA was prepared, digested with BamH I, blotted, and hybridized with acetylaminofluorene-labelled 16 + 23S rRNA from E. coil. The type strains of seven Rhodococcus species stud ied gave different hybridization patterns in each case. All strains te sted were clearly distinguishable by ribotyping. Patterns contained tw o to eight bands between 1.4 kb and 11.8 kb and demonstrated the high genetic divergence of genus Rhodococcus. Investigation of nine R. rhod ochrous strains resulted in patterns with seven or eight bands. One fr agment, 4.4 kb in size, was common to all R. rhodochrous strains and a ppears to be characteristic of R. rhodochrous. Ribotyping was evaluate d as a tool for distinguishing between Rhodococcus species.