Background: An accurate and rapid method for species identification of coagulase negative staphylococci (CNS) has been increasingly necessary for the clinical significance and planning the management of patients with staphylococcal infections. Recently, it has been reported that there is a highly conserved area on their 60KDa heat shock protein (HSP60) gene sequences between the interspecies of CNS and it can be amplified by a set of universal degenerate primer. This led us our attention to focus on whether the PCR-based RFLP method using Mse I restriction enzyme could be a useful tool for the species identification of CNS.

Methods: In the present study, we performed PCR-based RFLP analysis using a set of degenerate primers covering HSP60 and Mse I restriction enzyme on the seven reference strains and 25 clinical isolates (10 of S. epidermidis, 10 of S. haemolyticus, 4 of S. lugdunensis and 1 of S. warneri) which were previously identified by the API-STAPH, Vitek GPI card and/or with conventional biochemical test.

Results: All the seven reference strains revealed that each strain has a distinct electrophoresed band patterns with combination of different number (up to 8) and size of fragments. And these distinct band patterns showed remarkable concordance with the seven reference strains and 25 clinical isolates.

Conclusion: These results strongly suggest that the PCR-RFLP method using degenerate primers covering the HSP60 gene and Mse I digestion enzyme offer a convenient and accurate tool for species-specific identification of CNS. (Korean J Clin Microbiol 2000;3(1):36-42)