Impact of an Assay That Enables Rapid Determination of Staphylococcus Species and Their Drug Susceptibility on the Treatment of Patients with Positive Blood Culture Results

Objective. To determine whether an earlier determination of staphylococcal species and their antibiotic susceptibility decreases unnecessary antistaphylococcal treatment and/or facilitates earlier appropriate treatment. Methods. We used the Xpert MRSA/SA BC system (Cepheid) for immediate determination of species and their drug susceptibility in patients whose blood cultures revealed gram‐positive cocci in clusters. We compared the treatment of patients whose physicians received early notification of these results (group 1) with the treatment of patients in a historical cohort with delayed reporting after traditional microbiological studies (group 2). Outcomes were analyzed according to whether blood culture was positive for Staphylococcus species other than S. aureus, methicillin‐susceptible S. aureus (MSSA), or methicillin‐resistant S. aureus (MRSA) and whether the drugs used were appropriate for methicillin‐susceptible or methicillin‐resistant staphylococci (hereafter referred to as “MSS drug” or “MRS d...