The use of a nonradioactively labelled probe system in an electrophoretic ribotyping method for the differentiation of strains of coagulase-negative staphylococci.

Bacteria of the genus Staphylococcus are notoriously difficult to classify and identify; many routine hospital laboratories use only simple, older techniques to segregate them into broad groups. Recent studies have demonstrated that subspecific strains vary in their clinical significance and are of increasing importance in hospital-derived infections; this has led to a need for better methods of classification and identification. Restriction fragment length polymorphism analysis of genes for ribosomal RNA ('ribotyping') is potentially very useful since these genes occur in multiple copies in the genome, and are relatively stable. The restriction fragment patterns are sufficiently different to be usable in classification and identification. This paper considers an electrophoretic method for the separation of these restriction fragments which has the advantages of using a nonradioactive probe and a simple colour signal generating system for its evaluation. The technical principles are universal and would allow the procedure to be developed for other groups of microorganisms.