110. Impact of Diagnostic and Antimicrobial Stewardship on Time-to-Appropriate Therapy and Clinical Outcomes in Multi-Drug Resistant Pseudomonas Infections

Abstract

BackgroundTimely effective therapy in multi-drug resistant (MDR) Pseudomonas (PsA) infections has a direct impact on patient survival. We aimed to determine the impact of diagnostic and antimicrobial stewardship (AMS) on time-to-appropriate therapy (TAP) and clinical outcomes of patients with MDR PsA infections utilizing novel beta-lactam/beta-lactamase inhibitors (BL/BLIs).MethodsRetrospective cohort study of adult patients with MDR PsA infections at a 1,500-bed University-affiliated public hospital in Miami, Florida who received ≥72 hours of ceftazidime-avibactam (C/A) or ceftolozane-tazobactam (C/T). During the pre-intervention period (12/2017-12/2018), additional susceptibilities for C/A and C/T were performed upon providers’ request. In the post intervention period (01/2019 – 12/2019), we implemented automatic reflex algorithms (Figure 1) for faster identification and susceptibilities for MDR PsA, including carbapenemase producers. Results were communicated in real-time to the AMS team.Figure 1. Reflex Testing Algorithm for MDR Pseudomonas Isolates from Any Source ResultsSeventy-six patients were included; median age was 56 years (IQR 37.5–67.0), 40 (52.6%) were in an intensive care unit at time of culture collection; median APACHE II score was 20 (IQR 15.0 – 26.0). Three isolates were carbapenemase producers (VIM = 2; KPC = 1). The most common infections were pneumonia (56.6%) and bacteremia (18.4%). We found a significant decrease in median TAP (120.1 [IQR 82.5–164.6] vs 75.9 [IQR 51.3–101.7] hours, p = 0.003). Median time from culture collection to final susceptibility results was shorter in the post-intervention group (122.2 vs 90.5 hours; p < 0.001). Median length-of-stay after culture collection was numerically lower in the post-intervention group (26.0 [11.6–59.4] vs 19.7 [12.9–37.8] days; p = 0.33). Controlling for ICU admission, our intervention was not associated with decreased 30-day inpatient mortality (OR = 1.62, 95% CI 0.45–5.79).ConclusionOur study identified an improvement in TAP in MDR PsA infections with implementation of diagnostic and AMS initiatives. In an adequately powered study, our intervention could potentially impact patient survival through timely initiation of effective therapy with novel BL/BLIs.Disclosures All Authors: No reported disclosures