In vitro activity of Sulbactam-durlobactam and Standard-of-Care Antibiotics against Acinetobacter baumannii-calcoaceticus complex isolates from wound and urinary tract sources: ACNBio Study 2023-2025
Recommended Citation
Asempa TE, Cyr E, Argotsinger J, Beck ET, Chamberland RR, Daniels AR, Liesman R, Gialanella P, Hand J, Harrington A, Humphries R, Huse H, Hamilton-Seth R, Kufel WD, Riddell SW, Westblade L, Marino J, Narayanan N, Kirn T, Pierce VM, Potula R, Tekle T, Simner PJ, Mochon B, Hankins J, Fisher M, Dumm R, Mutnal MB, Jenkins TC, Chavez V. In vitro activity of Sulbactam-durlobactam and Standard-of-Care Antibiotics against Acinetobacter baumannii-calcoaceticus complex isolates from wound and urinary tract sources: ACNBio Study 2023-2025. Open Forum Infect Dis 2026; 13:S796.
Document Type
Conference Proceeding
Publication Date
1-11-2026
Publication Title
Open Forum Infect Dis
Keywords
antibiotic agent, carbapenem derivative, cefiderocol, durlobactam, durlobactam plus sulbactam, meropenem, sultamicillin, tetracycline derivative, Acinetobacter baumannii, Acinetobacter calcoaceticus-baumannii complex, bacteremia, bone biopsy, broth dilution, carbapenem resistant Acinetobacter baumannii, conference abstract, controlled study, Food and Drug Administration, health care quality, human, in vitro study, intensive care unit, MIC50, MIC90, nonhuman, pneumonia, soft tissue, soft tissue infection, urinary tract, urinary tract infection, wound
Abstract
Background. Acinetobacter baumannii most often causes nosocomial bacteremia and pneumonia. However, A. baumannii is becoming an important cause of a broader range of infections including skin and soft tissue infection (SSTI) and urinary tract infections (UTI). This study aims to evaluate the in vitro activity of sulbactamdurlobactam and other clinically utilized antibiotics against A. baumanniicalcoaceticus complex isolates isolated from non-respiratory and non-bloodstream sources. Methods. Samples included 193 A. baumannii-calcoaceticus complex isolates collected from 2023-2025 across 19 states. Susceptibility tests for sulbactamdurlobactam (durlobactam fixed concentration of 4 mg/L), and comparator agents were conducted by manual broth microdilution and interpreted according to CLSI and FDA (cefiderocol) standards. Results. A. baumannii complex isolates were primarily cultured from skin and soft tissue (56.5%), followed by urinary tract (31.6%) and other sources (11.9%) including bone biopsy, fluid aspirate etc. ICU patients contributed 20% of the isolates. Sulbactam-durlobactam was observed to be highly active (98.5% susceptible [S]; MIC50/90 1/4 mg/L), demonstrating greater activity than ampicillin-sulbactam (41.5% S; MIC50/90 8/32 mg/L) and meropenem (32.1% S; MIC50/90 32/128 mg/L). Sulbactam-durlobactam also displayed high susceptibility rates across sample sources, ranging from 97.3% (skin and soft tissue) to 100% (urine). The MIC50/90 and susceptibility rates for all other agents including tetracycline derivatives are shown in Table 1. Notably, among the carbapenem-resistant A. baumannii (CRAB) isolates (n=130) in the collection, sulbactam-durlobactam retained high activity (97.7% S) relative to ampicillin-sulbactam (16.2% S). Cefiderocol inhibited 97.7% and 75.4% of isolates at CLSI and FDA susceptible breakpoints, respectively. Conclusion. The data reported here are consistent with results from surveillance studies among non-respiratory and bloodstream isolates and show that sulbactamdurlobactam demonstrates in vitro activity against clinical A. baumannii complex isolates from urinary tract and SSTI sources, including isolates that are resistant to ampicillin-sulbactam, carbapenems, and cefiderocol.
Volume
13
First Page
S796
