(528) A Pharmacist-Driven MRSA PCR Algorithm in Critically Ill vs Non-Critically Ill Pneumonia Patients

Introduction: A pharmacist-driven methicillin-resistant Staphylococcus Aureus (MRSA) nasal polymerase chain reaction (PCR) based treatment algorithm has been shown to shorten gram-positive (GP) duration of therapy in a critically ill population with suspected pneumonia, but results have not been demonstrated in non-critically ill patients. It is hypothesized that an algorithm can be applied for use in both populations with similar impact.

Methods: Two parallel retrospective cohort studies with a critically ill and a non-critically ill cohort utilizing an equivalent study design were performed in a multi-site, tertiary healthcare system. In each cohort, a group utilizing a pharmacist-driven algorithm to order MRSA nasal PCR’s and deescalate antibiotic therapy based on results were compared to similar groups who did not utilize the algorithm. Adults who were admitted to the intensive care unit (ICU) (critically ill cohort) or a general medicine service (non-critically ill cohort) and received vancomycin or linezolid for suspected pneumonia were included. The primary endpoint was to compare impact of the algorithm on duration of anti-MRSA therapy based on patient level of care. Secondary endpoints included impact on hospital length of stay (LOS), in-hospital mortality, ordering of vancomycin levels and vancomycin-associated new-onset acute kidney injury (AKI).

Results: One hundred ninety-four patients (97 per group) were reviewed in the non-critically ill cohort and 100 (50 per group) in the critically ill cohort. Baseline characteristics between groups were similar in each cohort. The duration of anti-MRSA therapy was significantly lower in both cohorts: 38.8 hours shorter for non-critically ill (p < 0.001) and 48 hours shorter in critically ill (p < 0.001). There were also less vancomycin levels ordered in the algorithm group in both cohorts (0 vs. 2 levels in non-critically ill [p < 0.001] and 2 vs. 3 in critically ill [p=0.026]). Neither cohort showed a difference between groups in new onset AKI, hospital LOS or mortality.

Conclusions: A pharmacist-driven MRSA PCR algorithm can shorten the duration of GP antibiotic therapy and use of therapeutic drug monitoring in both critically ill and non-critically ill populations similarly. The treatment algorithm can be applied across transitions of care.