<i>In Vitro</i> Activity of Sulbactam-Durlobactam against Global Isolates of <i>Acinetobacter baumannii</i> - <i>calcoaceticus</i> Complex Collected from 2016 to 2021
James A. Karlowsky, Meredith Hackel, Sarah M. McLeod, Alita A. Miller
Abstract
activity of sulbactam-durlobactam was maintained across individual ABC species, years, global regions of collection, specimen sources, and resistance phenotypes, including MDR and extensively drug-resistant (XDR) isolates. At 4 μg/mL (preliminary sulbactam-durlobactam susceptible MIC breakpoint), sulbactam-durlobactam inhibited 98.3% of all ABC isolates and >96% of sulbactam-, imipenem-, ciprofloxacin-, amikacin-, and minocycline-non-susceptible isolates; as well as colistin-resistant, MDR, and XDR isolates. Most imipenem-non-susceptible ABC isolates (96.8%, 2,488/2,570) were carbapenem-resistant A. baumannii (CRAB); 96.9% (2,410/2,488) of CRAB isolates were sulbactam-durlobactam-susceptible. More than 80% of ABC isolates had sulbactam-durlobactam MIC values that were ≥2 doubling-dilutions (4-fold) lower than sulbactam alone. Only 1.7% (84/5,032) of ABC isolates from 2016 to 2021 had sulbactam-durlobactam MIC values of >4 μg/mL. Of the 84 isolates, 94.0% were A. baumannii, 4.8% were A. pittii, and 1.2% were A. nosocomialis. In summary, sulbactam-durlobactam demonstrated potent antibacterial activity against a 2016 to 2021 collection of geographically diverse clinical isolates of ABC isolates, including carbapenem-non-susceptible and MDR isolates.