riboprinting This method is based on restriction endonuclease digestion of bacterial chromosomal DNA, followed by Southern hybridization to probes for sequences in the regions of bacterial DNA coding for the 5S-16S-23S (the Escherichia coli rrnB rRNA operon) rRNA operon. The probes have been developed that are directed to highly conserved regions of the rRNA operon present in all eubacteria and can therefore be used for ribotyping most bacteria diagnostic test