Category: Professional Posters
Purpose: Polymerase chain reaction (PCR) nasal screening is an effective strategy to rule out methicillin-resistant Staphylococcus aureus (MRSA) and decrease use of vancomycin in lower respiratory tract infections. At Methodist Medical Center of Oak Ridge, opportunity to optimize vancomycin usage was identified in 2016. Investigators sought to assess the impact of a pharmacy-driven MRSA nasal screening program on pharmacists’ interventions and vancomycin utilization.
Methods: This single center, retrospective study evaluated the impact of a pharmacist-driven MRSA PCR nasal screening program on total vancomycin utilization, respiratory diagnosis-related group (DRG) vancomycin use, and length of stay in days (LOS) before (July 2016-June 2016) and after (July 2017-December 2018) implementation. Beginning in July of 2017, pharmacists screened all vancomycin and linezolid orders for known or suspected MRSA pneumonia, and subsequently ordered the nasal MRSA PCR test. Pharmacists contacted the prescriber for negative results to discuss discontinuation of anti-MRSA therapy. Patients were excluded if there was a concomitant infection requiring anti-MRSA therapy (e.g., empyema, cellulitis). Pharmacist intervention data was collected which included number of patients with MRSA nasal PCR ordered, nasal PCR test result, anti-MRSA agent used, discontinuation of the anti-MRSA agent, and the incidence of discontinuation within 24 hours of the nasal PCR order. Total vancomycin utilization, as measured by days of therapy per 1000 acute patient days (DOT/1000 PD) was determined before and after implementation. A DRG assignment for each patient screened for MRSA was determined, and the vancomycin days of therapy per 1000 DRG patient days (DOT/1000 DrgPD) and LOS were compared for the top 3 pneumonia related DRGs, as well as all respiratory DRGs that included MRSA PCR nasal screening patients. In addition, vancomycin DOT/1000 DrgPD and LOS were compared in all DRGs with vancomycin utilization.
Results: A total of 843 patients had an order for an MRSA PCR test in the post-implementation group. The results were negative in 673 patients (79.8%) and positive in 170 patients (20.2%). 640 patients (95.1%) had their anti-MRSA therapy discontinued, 546 (85.3%) within 24 hours. The agents prescribed were vancomycin in 823 patients (97.6%) and linezolid in 20 patients (2.4%). Post-implementation, there was no significant difference in mean (± SD) total vancomycin DOT/1000 PD [(225.4 ± 14.1) vs. (229.2 ± 16.3), p=NS] or DOT/1000 DrgPD in all DRGs [(176.8 ± 12.2) vs. (175.5 ± 14.1), p=NS]. A significant reduction in both mean (± SD) vancomycin DOT/1000 DrgPD was found in the top 3 pneumonia related DRGs [(214.8 ± 62.6) vs. (127.8 ± 47.8), p<0.001] and in all respiratory DRGs [(223.9 ± 35.5) vs. (198.4 ± 21.6), p=0.04]. No significant difference was found in length of stay for any DRG.
Conclusion: Implementation of a pharmacist-driven MRSA PCR nasal screening program in known or suspected pneumonia resulted in a high rate of vancomycin discontinuation in negative screen patients. Although no difference was observed in total vancomycin utilization in all DRGs, a significant reduction was observed for vancomycin within the top 3 pneumonia related DRGs as well as all respiratory DRGs, without negatively impacting length of stay. Determining vancomycin utilization in respiratory DRGs may be a useful strategy to assess the impact of a nasal screening program for pneumonia when no difference is observed in total DOT/1000 PD.