Identification of Staphylococcus aureus and determination of methicillin resistance directly from positive blood cultures by isothermal amplification and a disposable detection device.

A simple, rapid, and user-friendly procedure has been developed to identify Staphylococcus aureus and determine its methicillin resistance directly from gram-positive cocci in cluster-containing blood culture medium. The specimens were diluted and heated prior to amplification of the nuc and mecA genes with isothermal helicase-dependent amplification. Amplicons were detected using a disposable detection device. The analytical sensitivity of the assays was 50 CFU per reaction, and the clinical sensitivity and specificity were both 100% for S. aureus detection and 100% and 98% for methicillin resistance determination, respectively.