Effect of rapid methicillin-resistant Staphylococcus aureus nasal polymerase chain reaction screening on vancomycin use in the intensive care unit

Purpose. To determine the impact of a pharmacist-driven methicillin resistant Staphylococcus aureus (MRSA) nasal polymerase chain reaction (PCR) screen on vancomycin duration in critically ill patients with suspected pneumonia. Methods. This was a retrospective, quasi-experimental study at a 613bed academic medical center with 67 intensive care beds. Adult patients admitted to the intensive care unit (ICU) between 2017 and 2019 for 24 hours or longer and empirically started on intravenous vancomycin for pneumonia were included. The primary intervention was the implementation of a MRSA nasal PCR screen protocol. The primary outcome was duration of empiric vancomycin therapy. Secondary outcomes included the rate of acute kidney injury (AKI), the number of vancomycin levels obtained, the rate of resumption of vancomycin for treatment of pneumonia, ICU length of stay, hospital length of stay, the rate of ICU readmission, and the rate of in-hospital mortality. Results. A total of 418 patients were included in the final analysis. The median vancomycin duration was 2.59 days in the preprotocol group and 1.44 days in the postprotocol group, a reduction of approximately 1.00 day (P < 0.01). There were significantly fewer vancomycin levels measured in the postprotocol group than in the preprotocol group. Secondary outcomes were similar between the 2 groups, except that there was a lower rate of AKI and fewer vancomycin levels obtained in the postprotocol group (despite implementation of area under the curve-based vancomycin dosing) as compared to the preprotocol group. Conclusion. The implementation of a pharmacist-driven MRSA nasal PCR screen was associated with a decrease in vancomycin duration and the number of vancomycin levels obtained in critically ill patients with suspected pneumonia.