Pharmacist-Driven MRSA Nasal PCR Screening and the Duration of Empirical Vancomycin Therapy for Suspected MRSA Respiratory Tract Infections

OBJECTIVE: To assess the effect of a pharmacist-driven, polymerase chain reaction (PCR)−based nasal screening protocol for methicillin-resistant Staphylococcus aureus (MRSA) on vancomycin therapy duration and on rates of adverse drug events and 30-day hospital readmission. PATIENTS AND METHODS: From July 8, 2017, through January 31, 2019, we performed a retrospective, multicenter, preimplementation-postimplementation study. Patients with a vancomycin order to treat lower respiratory tract infection (LRTI) underwent MRSA PCR screening; tests were ordered by health care providers, including physicians, physician assistants, and advanced practice registered nurses. During the preimplementation period (July 8, 2017, through September 30, 2018), pharmacists could order MRSA PCR screening only after receiving a verbal order from a health care provider. During the postimplementation period (October 1, 2018, through January 31, 2019), a collaborative practice agreement allowed pharmacists to order MRSA PCR screening tests. RESULTS: The preimplementation group included 241 patients, and the postimplementation group included 74 patients. Of these patients, 124 in the preimplementation group and 62 in the postimplementation group received MRSA PCR screening. Twenty patients (16.1%) in the preimplementation group and 9 (14.5%) in the postimplementation group had a positive MRSA PCR screening test result (between-group difference, 1.6%; P=.80). Duration of therapy was significantly shorter in the postimplementation group (median [interquartile range], 14.3 [5.0-28.6] hours vs 24.0 [12.4-47.0] hours; P<.001). CONCLUSION: Vancomycin therapy carries a risk of adverse events and may increase health care costs. A pharmacist-driven protocol for MRSA nasal swab PCR screening effectively reduces the duration of vancomycin therapy for patients with lower respiratory tract infection.