Epidemiology and in vitro activity of ceftazidime-avibactam and comparator agents against multidrug-resistant isolates of Enterobacterales and Pseudomonas aeruginosa collected in Latin America as part of the ATLAS surveillance program in 2015‒2020.

Abstract

The incidence of antimicrobial resistance is increasing in many parts of the world. The focus of this report is to examine changes in antimicrobial resistance epidemiology among clinical isolates of Enterobacterales and Pseudomonas aeruginosa collected in six Latin American countries as part of the Antimicrobial Testing Leadership and Surveillance (ATLAS) program from2015to2020, with a focus on the in vitro activity of ceftazidime-avibactam against Multidrug-Resistant (MDR) isolates. Non-duplicate, clinical isolates of Enterobacterales (n=15,215) and P. aeruginosa (n=4,614) collected by40laboratories in Argentina, Brazil, Chile, Colombia, Mexico, and Venezuela, from2015to2020, underwent centralized Clinical Lab Standards Institute (CLSI) broth microdilution susceptibility testing. Minimum Inhibitory Concentration (MIC) values were interpreted using2022 CLSI breakpoints. An MDR phenotype was defined by resistance to≥ 3 of seven sentinel agents. In total, 23.3%of Enterobacterales and 25.1% of P. aeruginosa isolates were MDR. Annual percent MDR values for Enterobacterales were stable from2015to2018 (21.3%to23.7%year) but markedly increased in2019(31.5%) and 2020(32.4%). Annual percent MDR values for P. aeruginosa were stable from2015to2020 (23.0%to27.6%year). Isolates were divided into two3-year time-periods, 2015‒2017 and 2018‒2020, for additional analyses. For Enterobacterales, 99.3% of all isolates and 97.1% of MDR isolates from2015‒2017 were ceftazidime-avibactam-susceptible compared to97.2% and 89.3%of isolates, respectively, from 2018‒2020. For P. aeruginosa, 86.6%of all isolates and 53.9%of MDR isolates from2015‒2017 were ceftazidime-avibactam-susceptible compared to85.3% and45.3% of isolates, respectively, from2018‒2020. Among individual countries, Enterobacterales and P. aeruginosa collected in Venezuela showed the greatest reductions in ceftazidime-avibactam susceptibility over time. MDR Enterobacterales increased in Latin America from22% in2015to32% in2020 while MDR P. aeruginosa remained constant at 25%. Ceftazidime-avibactam remains highly active against all clinical isolates of both Enterobacterales (97.2%susceptible, 2018‒2020) and P. aeruginosa (85.3%), and inhibited more MDR isolates (Enterobacterales, 89.3% susceptible, 2018‒2020; P. aeruginosa, 45.3%) than carbapenems, fluoroquinolones, and aminoglycosides.