COMPARATIVE-EVALUATION OF A NEW MOLECULAR METHOD FOR TYPING STAPHYLOCOCCUS-EPIDERMIDIS

The discriminatory powers of several techniques for typing Staphylococcus epidermidis were evaluated in an epidemiological study of bacteria isolated from intensive care patients and from neonates. Genomic DNA fingerprinting using BclI restriction endonuclease was an effective epidemiological marker. The distinct restriction fragment profiles produced with this enzyme were highlighted with specific probes in a Southern blot technique. Cloned Escherichia coli rRNA gene probes proved to have lower discriminatory power and be less suitable for intraspecies typing. However, a panel of random genomic Staphylococcus epidermidis DNA clones provided almost the same level of discrimination as the DNA fingerprinting technique and also provided a clearer profile. DNA and gene fingerprinting techniques were reproducible and highly discriminatory compared to typing based on antigen and plasmid profiles, antibiotic susceptibility patterns and biotypes.