Background: Hospitals in the United States have been encouraged to report antimicrobial use (AU) to the CDC NHSN since 2011. Through the NHSN Antimicrobial Use Option module, health systems may compare standardized antimicrobial administration ratios (SAARs) across specific facilities, patient care locations, time periods, and antimicrobial categories. To date, participation in the NHSN Antimicrobial Use Option remains voluntary and the value of reporting antimicrobial use and receiving monthly SAARs to multihospital healthcare systems has not been clearly demonstrated. In this cohort study. we examined potential applications of SAAR within a healthcare system comprising multiple local hospitals. Methods: Three hospitals within Prisma Health-Midlands (hospitals A, B, and C) became participants in the NHSN Antimicrobial Use Option in July 2017. SAAR reports were presented initially in October 2017 and regularly (every 3–4 months) thereafter during interprofessional antimicrobial stewardship system-wide meetings until end of study in June 2019. Through interfacility comparisons and by analyzing SAAR categories in specific patient-care locations, primary healthcare providers and pharmacists were advised to incorporate results into focused antimicrobial stewardship initiatives within their facility. Specific alerts were designed to promote early de-escalation of antipseudomonal β-lactams and vancomycin. The Student t test was used to compare mean SAAR in the preintervention period (July through October 2017) to the postintervention period (November 2017 through June 2019) for all antimicrobials and specific categories and locations within each hospital. Results: During the preintervention period, mean SAAR for all antimicrobials in hospitals A, B, and C were 0.69, 1.09, and 0.60, respectively. Notably, mean SAARs at hospitals A, B, and C in intensive care units (ICU) during the preintervention period were 0.67, 1.36, and 0.83 for broad-spectrum agents used for hospital-onset infections and 0.59, 1.27, and 0.68, respectively, for agents used for resistant gram-positive infections. After antimicrobial stewardship interventions, mean SAARs for all antimicrobials in hospital B decreased from 1.09 to 0.83 in the postintervention period (P < .001). Mean SAARs decreased from 1.36 to 0.81 for broad-spectrum agents used for hospital-onset infections and from 1.27 to 0.72 for agents used for resistant gram-positive infections in ICU at hospital B (P = .03 and P = .01, respectively). No significant changes were noted in hospitals A and C. Conclusions: Reporting AU to the CDC NHSN and the assessment of SAARs across hospitals in a healthcare system had motivational effects on antimicrobial stewardship practices. Enhancement and customization of antimicrobial stewardship interventions was associated with significant and sustained reductions in SAARs for all antimicrobials and specific antimicrobial categories at those locations.

Funding: None

Disclosures: None