Rapid Multiplex Polymerase Chain Reaction-Based Blood Culture Identification

Ritu Banerjee, M.D., Ph.D.

The value of rapid, panel-based molecular diagnostics for positive blood culture bottles (BCBs) has not been rigorously assessed. Mayo Clinic researchers, first author Ritu Banerjee, M.D., Ph.D., performed a prospective randomized controlled trial evaluating outcomes associated with rapid multiplex PCR (rmPCR) detection of bacteria, fungi, and resistance genes directly from positive BCBs. The study was published in the Clinical Infectious Diseases journal.

During the study, 617 patients with positive BCBs underwent stratified randomization into three arms: standard BCB processing, rmPCR reported with templated comments, or rmPCR reported with templated comments and real-time audit and feedback of antimicrobial orders by an antimicrobial stewardship team. The primary outcome was antimicrobial therapy duration. Secondary outcomes were time to antimicrobial de-escalation or escalation, length of stay (LOS), mortality, and cost.

Researchers found that use of the rmPCR test led to more judicious antibiotic use. Additionally, they delivered rapid test results along with templated comments guiding interpretation and antimicrobial prescribing, and separately evaluated this approach with and without real-time antimicrobial stewardship. Both rapid test reporting strategies reduced unnecessary antibiotic use, although rmPCR testing combined with antimicrobial stewardship resulted in the most rapid antibiotic de-escalation.

Based on the results, rapid pathogen and susceptibility detection directly from blood cultures implemented with templated comments or antimicrobial stewardship oversight can optimize antibiotic prescribing for bloodstream infections. To influence clinical decision making, rapid results should be delivered with real-time decision support (using automated systems or antimicrobial stewardship programs) that assists clinicians to interpret and act on results.

Kelley Luedke (@kschrib)

Kelley Luedke

Kelley Luedke is a Marketing Channel Manager at Mayo Clinic Laboratories. She is the principle editor and writer of Insights and leads social media and direct marketing strategy. Kelley has worked at Mayo Clinic since 2013. Outside of work, you can find Kelley running, traveling, playing with her kitty, and exploring new foods.