SPECIES-SPECIFIC AND UBIQUITOUS-DNA-BASED ASSAYS FOR RAPID IDENTIFICATION OF STAPHYLOCOCCUS-AUREUS

Staphylococcus aureus is the cause of serious infections in humans, in cluding endocarditis, deep-seated abscesses, and bacteremia, which lea d to toxic and septic shock syndromes. Rapid and direct identification of this bacterium specifically and ubiquitously directly from clinica l specimens would be useful in improving the diagnosis of S. aureus in fections in the clinical microbiology laboratory. A wide variety of ki ts based on biochemical characteristics efficiently identify S. aureus , but the rapidity and the accuracy of each of these methods combined with testing of clinically relevant antibiotic resistance genes need t o be improved. On the basis of hybridization assays with randomly sele cted clones from an S. aureus genomic library, we have identified a ch romosomal DNA fragment which is specific for S. aureus and which detec ted all 82 S. aureus isolates tested. This 442-bp fragment was sequenc ed and was used to design a set of PCR amplification primers. The PCR assay was also specific and ubiquitous for the identification from bac terial cultures of 195 clinical strains of S. aureus isolated from a v ariety of anatomical sites and obtained from hospitals throughout the world. The PCR assay that we have developed is simple and can be perfo rmed in about 1 h. This DNA-based test provides a novel diagnostic too l for the diagnosis of S. aureus infections.