Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targetsmecA,femAspecific forS. aureus,femAspecific forS. epidermidis,16S rRNAfor universal bacteria, and16S rRNAspecific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistantS. aureus(MRSA), methicillin-susceptibleS. aureus(MSSA), methicillin-resistantS. epidermidis(MRSE), methicillin-susceptibleS. epidermidis(MSSE), methicillin-resistant non-S. epidermidisCoNS (MRCoNS), and methicillin-susceptible non-S. epidermidisCoNS (MSCoNS) (κ=0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings.
Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia