Critical Care Medicine
INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) infections are associated with prolonged hospital length of stay and mortality rates up to 20%. Risk factors for MRSA and presumed type of infection often guide vancomycin prescribing. This study evaluated the presence of MRSA risk factors in emergent and critically ill patients who received vancomycin therapy. METHODS: This retrospective study evaluated emergent and critically ill patients who received vancomycin for at least 24 hours for a presumed infection from 1/2020—3/2020. Patients were excluded if vancomycin was administered for surgical prophylaxis. Patients were divided into groups: MRSA Risk (MRSA-R) vs MRSA No Risk (MRSA-NR). MRSA risk factors were defined and collected. Culture data were evaluated 48 hours before and 72 hours after initiation of vancomycin. SPSS v21.0 was used for analysis. RESULTS: Of the 1053 emergent and critically ill patients identified 469 patients were included for analysis (MRSA-R n=208 vs MRSA-NR n=261). Patients were predominantly male (58%) with a mean age of 63.8 ±15.9 years. Baseline vitals were similar between groups. Only 7% of patients had SBP < 90 mmHg and incidence was similar between groups (p=0.58). Overall, 56% of patients received vancomycin without any MRSA risk factors. MRSA was identified on culture in 40 patients (10% MRSA-R v 7% MRSA-NR, p=0.27), and MRSA nares screening was positive in 3 patients (0.6%). Of the 208 patients with MRSA-R, the most common risk factor identified was antibiotic use within 90 days (52%). Of the MRSA-R group, 69% had at least 1 risk factor and 31% had > 2 risks. Vancomycin was more prescribed in MRSA-R patients in the emergency department (47% MRSA-R v 25% MRSA-NR, p< 0.001) compared to MRSA-NR patients in the ICU (19% MRSA-NR vs 6% MRSA-R, p< 0.001). MRSA-NR patients tended to receive more vancomycin doses (5.4±4.1 MRSA-NR v 4.7±4.0 MRSA-R, p=0.08). There were no differences in length of stay (p=0.71) or in-hospital mortality between groups. CONCLUSIONS: MRSA infections are associated with negative sequelae. In this study, vancomycin was empirically prescribed in over half of patients without MRSA risk factors and MRSA was minimally identified on culture. In supporting antimicrobial stewardship, additional efforts are needed to optimize empiric use of vancomycin.
Ragsdale M, Zimmerman LH, Messana E, Volgyi D. Evaluation of vancomycin based on risk factors in emergent and critically ill patients. Crit Care Med. 2022 Jan;50(1):438. doi: 10.1097/01.ccm.0000809864.79510.53.