Comparison of an improved RAPD fingerprinting with different methods for discriminating clinical isolates of Staphylococcus spp.

Different epidemiological markers were used to characterize 2 Staphylococcus epidermidis and 8 Staphylococcus aureus strains isolated from patients with severe infections. We compared random amplified polymorphic DNA (RAPD) fingerprints, biotypes, antibiotic assays, plasmid profiles and chromosomal DNA restriction endonuclease analysis (REA). Data analysis based on numerical taxonomy methods indicates that RAPD and REA give similar results allowing a good discrimination of the two species and of each isolate. The RAPD method is easier and faster than REA, but the reproducibility of RAPD fingerprints obtained in independent experiments can be problematic. We have found simple technical devices to improve the reproducibility of the RAPD procedure which is therefore a very useful tool in epidemiology for identification and characterization of Staphylococcus spp.