1244. In Vitro Activity of Ceftazidime-Avibactam and Comparator Agents Against MDR Enterobacterales and Pseudomonas aeruginosa Collected in Latin America During the ATLAS Global Surveillance Program 2018-2019

Abstract Background Ceftazidime-avibactam (CAZ-AVI) is a β-lactam/non-β-lactam β-lactamase inhibitor combination that can inhibit class A, C, and some D β-lactamases. Resistance caused by these β-lactamases often results in multidrug-resistance (MDR). This study evaluated the vitro activity of CAZ-AVI comparators against MDR Enterobacterales Pseudomonas aeruginosa isolates collected from patients Latin America. Methods Non-duplicate clinical were 2018-2019 10 countries Susceptibility testing was performed using CLSI broth microdilution interpreted 2021 FDA (tigecycline) breakpoints. defined as resistant (R) to ≥3 7 sentinel drugs: amikacin (AMK), aztreonam (ATM), cefepime (FEP), colistin (CST), levofloxacin (LVX), meropenem (MEM), piperacillin-tazobactam (TZP). Results The all subsets shown table. rates for studied species ranged 16.3% among E. cloacae 35.7% K. pneumoniae. active 98% maintained 74-98% examined species. Only tigecycline showed higher activity. Among P. aeruginosa, 87% 47% isolates; no other drug more active. three most common phenotypes 1) R ATM, FEP, LVX (n=544, 44.8% Enterobacterales; 100% susceptible (S) CAZ-AVI), 2) LVX, TZP (n=150, 12.4% 99.3% S 3) drugs except AMK CST (n=145, 11.9% 78.6% CAZ-AVI). (n=85, 19.7% 24.7% (n=42, 9.7% 66.7% AMK, MEM (n=37, 8.6% 24.3% Conclusion These data suggest be an effective treatment option infections Disclosures Sibylle Lob, PhD, IHMA (Employee)Pfizer, Inc. (Independent Contractor) Meredith Hackel, PhD MPH, Gregory Stone, AztraZeneca (Shareholder, Former Employee)Pfizer, (Employee) Daniel F. Sahm,