Category: Professional Posters
Purpose: Vancomycin is often included in the empiric regimen for pneumonia when there is a concern for methicillin-resistant Staphylococcus aureus (MRSA). Recent data indicate that MRSA nasal screenings have a high negative predictive value among all types of pneumonia, ruling out MRSA as a lower respiratory pathogen. As a result, MRSA nasal screenings emerged as an antimicrobial stewardship tool for pneumonia to encourage discontinuation of vancomycin if MRSA screening result is negative. The purpose of this study is to evaluate the impact of a vancomycin stewardship pilot with prescriber education utilizing MRSA nasal screenings on the usage of vancomycin for pneumonia.
Methods: The institutional review board exempted this retrospective, quasi-experimental, pre-post intervention study comparing 70 patients during two ten-week periods before (n equals 39) and after (n equals 31) the implementation of a vancomycin stewardship pilot protocol. The pilot consisted of continuing the institutional protocol to screen all admitted patients for MRSA colonization with chromogenic agar medium, creating a vancomycin stewardship protocol to guide the interpretation of nasal screening results and antibiotic selection in pneumonia, educating prescribers and pharmacists on the protocol, and incorporating a pharmacy-driven nasal screening surveillance process for all vancomycin per pharmacy orders indicated for pneumonia. Inclusion criteria are patients 18 years and older with community acquired pneumonia (CAP) with a history of multi-drug resistant organisms (MDRO), hospital-acquired pneumonia, and ventilator-associated pneumonia, and received vancomycin per pharmacy dosing for the indication of pneumonia. Exclusion criteria include septic shock, alternative indications for vancomycin, cavitary pulmonary lesions, febrile neutropenia, and CAP without a history of MDRO. The primary outcome was vancomycin duration of therapy. Secondary outcomes include length of stay, incidence of acute kidney injury (AKI), all-cause mortality during admission, and the predictive values of MRSA nasal screening for pneumonia. Subgroup analysis was performed on non-MRSA pneumonia cohorts. Statistical analysis was based on an alpha value of 0.05, requiring 70 patients to achieve 80 percent power to detect 50 percent reduction in vancomycin duration of therapy.
Results: The absolute difference of total vancomycin duration of therapy between the historical group and the pilot group was 51 days or 46.4%. The mean difference of vancomycin duration of therapy per patient was 0.9 days or 32.1% reduction (p=0.22). There were similar length of stays (15 days versus 17.6 days, p equals 0.38), AKI (0 cases versus 3 cases, p equals 0.05), and all-cause mortality (9 cases versus 2 cases, p equals 0.06) between the historical and the pilot groups. The positive predictive value was 60 to 66 percent and the negative predictive value was 92 to 93 percent. In the subgroup analysis, vancomycin use for non-MRSA pneumonia occurred 80 percent of the time in both groups (31 cases vs 25 cases, p equals 0.90). Among this cohort, the pilot group had significantly more discontinuations of vancomycin before a negative nasal screening result (9.7 percent versus 32.0 percent, p equals 0.04). Among the pilot group with non-MRSA pneumonia, prescribers discontinued vancomycin without requiring pharmacy intervention 76 percent of the time. Of the 24 percent requiring pharmacy intervention, 100 percent of the interventions were accepted.
Conclusion: The implementation of a vancomycin stewardship pilot utilizing MRSA nasal screening in pneumonia was associated with a trend towards reduction in vancomycin duration of therapy while maintaining similar clinical outcomes, as reflected by similar length of stays and all-cause mortality rates. Prescriber education is crucial in ensuring judicious use of vancomycin as depicted by a greater number of vancomycin orders discontinued prior to nasal screening results.