Antimicrobial activity of sulbactam-durlobactam against Acinetobacter baumannii-calcoaceticus complex strains causing non-respiratory and non-bloodstream infections from the United States (2023-2025)

Elizabeth Cyr, Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA.
Jill Argotsinger, Advocate Health - MidwestFollow
Eric T. Beck, Advocate Health - MidwestFollow
Robin R. Chamberland, Department of Pathology, Saint Louis University School of Medicine, , St. Louis, Missouri, USA.
Andrew E. Clark, Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Anne R. Daniels, Froedtert & Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Rachael Liesman, Froedtert & Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Mark Fisher, Department of Pathology, University of Utah School of Medicine, , Salt Lake City, Utah, USA.
Philip Gialanella, Department of Pathology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA.
Jonathan Hand, Department of Infectious Diseases, Ochsner Health, New Orleans, Louisiana, USA.
Amanda T. Harrington, Loyola University Medical Center, Maywood, Illinois, USA.
Romney M. Humphries, Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Holly Huse, Department of Pathology, Harbor-UCLA Medical Center, Torrance, California, USA.
Robert Hamilton-Seth, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA.
Julia D. Hankins, Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA.
Wesley D. Kufel, State University of New York Upstate University Hospital, Syracuse, New York, USA.
Scott W. Riddell, State University of New York Upstate University Hospital, Syracuse, New York, USA.
Meera Mehta, West Virginia University Hospitals, Morgantown, West Virginia, USA.
Ryan Demkowicz, Department of Pathology, West Virginia University School of Medicine, Morgantown, West Virginia, USA.
A Brian Mochon, Banner Health, Phoenix, Arizona, USA.
Hossein Salimnia, Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan, USA.
Ayesha Khan, Department of Pathology and Laboratory Medicine, UC Irvine School of Medicine, Irvine, California, USA.
Virginia M. Pierce, Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Raghava Potula, Pathology and Laboratory Medicine, Temple University Health System, Philadelphia, Pennsylvania, USA.
Tsigereda Tekle, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Patricia J. Simner, Department of Pathology, University of Utah School of Medicine, , Salt Lake City, Utah, USA.
Robert J. Tibbetts, Pathology and Laboratory Medicine, Henry Ford Health, Detroit, Michigan, USA.
Christine Vu, Department of Pharmacy, Jackson Health System, Miami, Florida, USA.
Lilian M. Abbo, Department of Pharmacy, Jackson Health System, Miami, Florida, USA.
Octavio Martinez, Department of Pathology, University of Miami Miller School of Medicine, Miami, Florida, USA.
et al

Affiliations

Advocate Lutheran General Hospital

Abstract

Acinetobacter baumannii most often causes pneumonia in critically ill patients. However, A. baumannii is also an important cause of a broader range of infections, including skin/wound and urinary tract infections. This study aims to evaluate the in vitro activity of sulbactam-durlobactam and comparator antibiotics, including meropenem and cefiderocol against A. baumannii-calcoaceticus complex isolates from non-respiratory and non-bloodstream sources. Samples included 285 A. baumannii-calcoaceticus complex isolates enriched for carbapenem resistance collected across 17 states in the United States (January 2023-May 2025). Antimicrobial susceptibility tests were conducted by manual broth microdilution and interpreted according to Clinical and Laboratory Standards Institute (CLSI) and Food and Drug Administration (FDA) (cefiderocol) standards. A. baumannii complex isolates were primarily cultured from skin/wound (58.6%), urinary tract (31.6%), and other sources (9.8%), including cerebrospinal and peritoneal fluid. Carbapenem resistance was observed in approximately 70% of isolates and more common among skin/wound cultures. Sulbactam-durlobactam was observed to be highly active (96.9% susceptible [S]; MIC90 4 mg/L) and demonstrated greater activity than sulbactam (37.9% S; MIC90 32 mg/L). Sulbactam-durlobactam also displayed high susceptibility rates across isolate sources, ranging from 96.4 (skin/wound) to 97.8% (urine). Cefiderocol demonstrated similar in vitro activity across culture sources and patient location, inhibiting >90 and >80% of isolates at CLSI and FDA susceptible breakpoints, respectively. Minocycline susceptibility was 69.1%, while tigecycline and eravacycline MICs50/90 were 1/4 and 0.5/1 mg/L, respectively. The observed data are consistent with results from surveillance studies among respiratory and bloodstream isolates and show that sulbactam-durlobactam demonstrates potent in vitro activity against clinical A. baumannii complex isolates from a variety of culture sources.IMPORTANCEAcinetobacter baumannii is a difficult-to-treat pathogen that often affects hospitalized patients and is known for a high level of multi-drug resistance. While commonly associated with pneumonia, it also causes infections in wounds, the urinary tract, and other parts of the body. This study shows that sulbactam-durlobactam is highly effective against A. baumannii from various infection sites. The results are important because they can inform clinicians on the susceptibility profiles of A. baumannii from a variety of infection sources, not just lung and bloodstream. As new antibiotics come onto the market, it is important to continuously assess resistance patterns to inform patient and system-wide health decisions.

Document Type

Article

PubMed ID

41869812

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