Evaluation of a Pharmacist-Led Methicillin-Resistant Staphylococcus aureus Nasal PCR Testing Protocol

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) can cause cases of community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia, and nasal colonization with this pathogen increases the risk of infection. Due to its high negative predictive value, multiple studies support using the MRSA nasal polymerase chain reaction (PCR) test to discontinue antimicrobials that target MRSA in the setting of a negative test result. The purpose of this project was to assess the utility of a protocol to allow pharmacists the ability to order MRSA nasal PCR screenings in hospitalized patients with pneumonia. Results: The pre-protocol group included a random sample of 100 patients, and the post-protocol group included 625 patients. Vancomycin DOTs when pharmacists ordered PCRs were significantly lower compared to the pre-protocol group (p < 0.5; 95% CI, 0.46-2.24). The average length of stay and readmission rates at 30 days were significantly lower in the post-protocol group compared to the pre-protocol group (p < 0.05 and p = 0.02, respectively), but there was no significant difference in mortality (p = 0.33). Methods: A protocol was implemented at our institution that allowed pharmacists to order an MRSA nasal PCR test in patients with pneumonia. This retrospective chart review compared a cohort of patients who received vancomycin from before implementation of the protocol to patients who received vancomycin after the protocol's implementation. The primary endpoint was vancomycin days of therapy (DOTs) between the pre-protocol group and the post-protocol group. Other endpoints assessed included the length of hospitalization, readmission rates, and mortality. Conclusions: Pharmacists ordering MRSA nasal PCR tests significantly reduced vancomycin DOTs, average length of stay, and 30-day readmission rates, contributing to positive outcomes in patients with pneumonia.