Resistance of Acinetobacter baumannii Complex Clinical Isolates to Sulbactam-Durlobactam: A Systematic Review of Data...

Due to the limited therapeutic options for patients with Acinetobacter baumannii complex infections, a new combination antimicrobial agent, sulbactam-durlobactam, has been developed. In this systematic review, we evaluated the available data on the resistance of A. baumannii complex clinical isolates to sulbactam-durlobactam.

We performed a thorough search of four databases for relevant studies. The Clinical and Laboratory Standards Institute (CLSI) sulbactam-durlobactam breakpoint for A. baumannii complex susceptibility was used (MIC value ≤4 mg/L). Data on the presence of genes of various β-lactamases were also analyzed.

From 182 identified articles, 84 were thoroughly screened. Data extraction was performed on 20 articles (published 2017-2025) reporting on a total of 10,412 A. baumannii complex clinical isolates. Among the various β-lactamases genes present, the OXA subvariants OXA-23/OXA-23-like were the most common (in 561 isolates). The proportions of non-selected (consecutive) A. baumannii isolates found to be resistant to sulbactam-durlobactam were 1.2%, 1.2%, and 4.6% in the three studies, and with non-susceptibility (resistance and intermediate resistance) were 2%, 2.1%, and 4.6% in three other studies. Non-susceptibility was very rare among A. calcoaceticus, A. nosocomialis, and A. pittii isolates (0%, 0.3%, and 0.6%, respectively). The proportion of carbapenem-resistant A. baumannii isolates with resistance was 0-5.2%. The proportion of A. baumannii isolates selected for their reduced susceptibility profile (including reduced susceptibility to cefiderocol) with resistance was 1.4-27.3%.

The low proportion of sulbactam-durlobactam resistance among A. baumannii complex isolates supports the consideration of the use of this new antibiotic for its approved indications.