Impact of a Pharmacist-Driven MRSA Nasal PCR Protocol on Pneumonia Therapy

Background:Methicillin-resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) testing can rapidly detect MRSA colonization via nasopharyngeal swab. With a high negative predictive value for MRSA pneumonia, this test may help minimize the duration of anti-MRSA therapy and associated adverse drug events. Objective: This study aimed to evaluate the impact of a pharmacist-initiated MRSA nasal PCR protocol on pneumonia therapy. Methods: This retrospective, quasi-experimental study evaluated adult patients with pneumonia before and after the implementation of a pharmacist-initiated MRSA nasal PCR protocol. The primary outcome of this study was to compare duration of anti-MRSA therapy between the Pre-PCR group and PCR group. Secondary comparisons included duration of antipseudomonal therapy, time from intravenous (IV) to oral interchange, and clinical outcomes. Results: In total, 210 patients (Pre-PCR: n = 138, PCR: n = 72) were included. The MRSA nasal PCR result was negative for 63 patients (87.5%), and 56 (88.9%) vancomycin orders were discontinued within 24 hours of the negative result. The mean duration of vancomycin therapy was significantly shorter in the PCR group (2.5 vs 1.4 days, P < .001) as well as duration of IV therapy (5 vs 3.9 days, P = .003). There was no difference between groups in duration of antipseudomonal therapy (P = .425), acute kidney injury (AKI; P = .332), 30-day readmission (P = .137), or 30-day mortality (P = .179). Conclusion and Relevance: A pharmacist-driven MRSA nasal PCR protocol significantly decreased the duration of anti-MRSA therapy and IV antibiotics in patients with pneumonia. These findings add to the relatively small body of literature supporting pharmacist-initiated rapid diagnostic testing and follow-up.