Conference Coverage

Rapid MRSA PCR Testing in Emergency Department Skin and Soft Tissue Infection Protocol Shows Mixed Impact on Antibiotic Stewardship

Edited by:
Kate Young

Key Highlights:

  • Implementation of a standardized soft tissue infection protocol incorporating methicillin-resistant Staphylococcus aureus polymerase chain reaction testing improved protocol adherence and increased single-agent therapy use.
  • Dual antibiotic therapy significantly decreased post-implementation.
  • Time to antibiotic de-escalation did not improve, largely due to prescriber resistance to ordering rapid diagnostic tests.
  • Findings underscore ongoing educational needs in emergency department antimicrobial stewardship.

A study presented at the ASHP Midyear Clinical Meeting and Exhibition examined whether adding rapid methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) wound swab testing to a standardized emergency department standardized soft tissue infection (SSTI) protocol could optimize antibiotic prescribing. The research assessed protocol adherence, appropriateness of therapy selection, and the impact on time to antibiotic de-escalation.

Investigators evaluated adult patients treated in the emergency department (ED) for soft tissue infections (SSTIs) during 2 periods: January–March 2024 (pre-implementation) and January–March 2025 (post-implementation). Purulent infections required MRSA PCR (PCRAssay) testing, while patients with prior MRSA infection, positive blood cultures, or concurrent MRSA infection unrelated to the SSTI were excluded. The primary outcome was ED provider adherence to the SSTI protocol—categorized as complete, partial, or non-adherent. The secondary outcome was mean time to antibiotic de-escalation. Chi-squared and independent t-tests were used for statistical analysis.

Study Findings

Among 514 screened patients, 94 were included pre-implementation and 112 post-implementation. After initiating the protocol, provider adherence was 33% complete, 43.6% partial, and 23.4% non-adherent. Antibiotic prescribing patterns shifted notably: single-agent therapy increased from 43.3% to 74.6%, while dual therapy declined from 56.7% to 25.4% (P = .0091).

Despite improved antibiotic selection and increased use of targeted therapy, the mean time to antibiotic de-escalation did not improve. Investigators attributed the lack of change to prescriber reluctance to order MRSA PCR testing, which delayed actionable diagnostic information.

Clinical Implications

The integration of rapid MRSA PCR testing within a structured SSTI protocol enhanced antimicrobial stewardship by reducing unnecessary broad-spectrum coverage and promoting guideline-concordant therapy. However, the study’s findings indicate that diagnostic tools alone are insufficient to accelerate de-escalation without consistent provider adoption. The authors emphasized that continued provider education and engagement are essential to fully realize the benefits of rapid diagnostics in the ED environment.

Expert Commentary

“Standardized SSTI protocols with rapid diagnostics improved appropriate antibiotic selection and supported antimicrobial stewardship efforts. However, despite full protocol implementation in the ED, time to de-escalation remained unchanged, highlighting the need for ongoing provider education,” the researchers concluded.

Reference
Barak A, Sikand H, Wong HS. Can incorporating rapid diagnostic tests into an emergency department skin and soft tissue infection protocol reduce time to antibiotic de-escalation? Presented at: ASHP Midyear Clinical Meeting and Exhibition; December 7-10, 2025; Las Vegas, NV. Accessed December 5, 2025. https://www.ashp.org/meetings-and-conferences/midyear-clinical-meeting-and-exhibition