1708. In vitro Activities of Ceftazidime-Avibactam and Comparator Agents against Enterobacterales and Pseudomonas aeruginosa Collected < 48 Hours and ≥48 Hours Post-Admission from Hospitalized Pediatric Patients, ATLAS Global Surveillance Program 2017-2020

Abstract

Abstract Background Ceftazidime-avibactam (CAZ-AVI) is a β-lactam combined with a diazabicyclooctane-β-lactamase inhibitor for treatment of infections caused by Gram-negative pathogens. Ceftazidime-avibactam is active against Enterobacterales (Ent) and P. aeruginosa (Psa) isolates that produce Class A, C and some Class D β-lactamases. This study examined the in vitro activity of CAZ-AVI and comparators against Ent and Psa from presumed community-acquired (CA; cultured < 48 h after hospital admission) and hospital-acquired (HA; cultured ≥48 h post-admission) infections collected from pediatric patients as part of the ATLAS surveillance program, 2017-2020. Methods 5765 non-duplicate Ent and 1987 Psa isolates from pediatric patients (≤17 y.o.) were collected from 241 sites in 54 countries as part of ATLAS 2017-2020 (excluding North America) for which the length of hospitalization stay was specified. Antimicrobial susceptibility testing was by broth microdilution according to CLSI guidelines and analyzed using CLSI 2022 breakpoints. Ent isolates testing with meropenem MICs >1 µg/mL and Escherichia coli, Klebsiella pneumoniae, K. oxytoca, K. variicola, and Proteus mirabilis testing with ceftazidime and/or aztreonam MICs >1 mg/L were genetically screened for β-lactamases. For Psa, meropenem MIC >2 µg/mL triggered β-lactamase screening. In 2020, approximately 25% of the meropenem non-susceptible isolates were screened. Results Against Ent, the in vitro activity of CAZ-AVI exceeded that of meropenem and other tested agents for both the presumed CA- and HA-infection sets. The addition of AVI to CAZ increased the %S from 76.1% to 97.5% for the CA-infection population, and from 62.2% to 96.1% for the HA-infection population. For Psa There was a larger difference between the %S to CAZ-AVI of the presumed CA set (93.3% S) and the HA set (89.8% S). For both Psa populations, CAZ-AVI was the most active drug among the comparators. Conclusion CAZ-AVI demonstrated potent in vitro activity against Enterobacterales and P. aeruginosa isolates collected globally from pediatric patients in 2017-2020, regardless of whether is infection was community-or hospital-acquired. Disclosures All Authors: No reported disclosures.