Differentiation of Rhodococcus species by ribotyping.

The ribosomal RNA gene restriction patterns (ribotyping) was investigated with respect to the characterization of Rhodococcus species and R. rhodochrous strains. Chromosomal DNA was prepared, digested with BamH I, blotted, and hybridized with acetylaminofluorene-labelled 16 + 23S rRNA from E. coli. The type strains of seven Rhodococcus species studied gave different hybridization patterns in each case. All strains tested were clearly distinguishable by ribotyping. Patterns contained two to eight bands between 1.4 kb and 11.8 kb and demonstrated the high genetic divergence of genus Rhodococcus. Investigation of nine R. rhodochrous strains resulted in patterns with seven or eight bands. One fragment, 4.4 kb in size, was common to all R. rhodochrous strains and appears to be characteristic of R. rhodochrous. Ribotyping was evaluated as a tool for distinguishing between Rhodococcus species.