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

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

  • Microbiol Spectr. 2026 Mar 23;14(5):e0328925. doi: 10.1128/spectrum.03289-25.
Elizabeth Cyr 1,  Jill Argotsinger 2,  Eric T Beck 3,  Robin R Chamberland 4,  Andrew E Clark 5,  Anne R Daniels 6,  Rachael Liesman 6 7 8,  Mark Fisher 9 10,  Philip Gialanella 11,  Jonathan Hand 12,  Amanda T Harrington 13,  Romney M Humphries 14,  Holly Huse 15,  Robert Hamilton-Seth 16,  Julia D Hankins 16,  Wesley D Kufel 17 18 19,  Scott W Riddell 17 19,  Meera Mehta 20,  Ryan Demkowicz 21,  A Brian Mochon 22 23 24,  Hossein Salimnia 25,  Ayesha Khan 26,  Virginia M Pierce 27,  Raghava Potula 28,  Tsigereda Tekle 29,  Patricia J Simner 9,  Robert J Tibbetts 30,  Christine Vu 31,  Lilian M Abbo 31 32,  Octavio Martinez 33,  Rebekah E Dumm 34,  Manohar B Mutnal 35,  Timothy C Jenkins 36,  Violeta Chávez 37,  Paulette Pinargote 38,  Jennifer Bowling 39,  Erik Munson 40,  Daniel V Zurawski 1,  David P Nicolau 1 41,  Tomefa E Asempa 1,  Acinetobacter baumannii Complex National Biorepository (ACNBio) Study Group
Affiliations

Affiliations

  • 1 Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut, USA.
  • 2 Advocate Lutheran General Hospital, Chicago, Illinois, USA.
  • 3 Department of Microbiology, ACL Laboratories, West Allis, Wisconsin, USA.
  • 4 Department of Pathology, Saint Louis University School of Medicine, , St. Louis, Missouri, USA.
  • 5 Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
  • 6 Froedtert & Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
  • 7 Department of Pathology, Froedtert & Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
  • 8 Wisconsin Diagnostic Labs, Milwaukee, Wisconsin, USA.
  • 9 Department of Pathology, University of Utah School of Medicine, , Salt Lake City, Utah, USA.
  • 10 Associated Regional and University Pathologists Laboratories, Salt Lake City, Utah, USA.
  • 11 Department of Pathology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, USA.
  • 12 Department of Infectious Diseases, Ochsner Health, New Orleans, Louisiana, USA.
  • 13 Loyola University Medical Center, Maywood, Illinois, USA.
  • 14 Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
  • 15 Department of Pathology, Harbor-UCLA Medical Center, Torrance, California, USA.
  • 16 Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA.
  • 17 State University of New York Upstate University Hospital, Syracuse, New York, USA.
  • 18 Binghamton University School of Pharmacy and Pharmaceutical Sciences, Binghamton, New York, USA.
  • 19 State University of New York Upstate Medical University, Syracuse, New York, USA.
  • 20 West Virginia University Hospitals, Morgantown, West Virginia, USA.
  • 21 Department of Pathology, West Virginia University School of Medicine, Morgantown, West Virginia, USA.
  • 22 Banner Health, Phoenix, Arizona, USA.
  • 23 Sonora Quest Laboratories, Phoenix, Arizona, USA.
  • 24 Department of Pathology, University of Arizona College of Medicine, Phoenix, Arizona, USA.
  • 25 Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan, USA.
  • 26 Department of Pathology and Laboratory Medicine, UC Irvine School of Medicine, Irvine, California, USA.
  • 27 Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
  • 28 Pathology and Laboratory Medicine, Temple University Health System, Philadelphia, Pennsylvania, USA.
  • 29 Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
  • 30 Pathology and Laboratory Medicine, Henry Ford Health, Detroit, Michigan, USA.
  • 31 Department of Pharmacy, Jackson Health System, Miami, Florida, USA.
  • 32 Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA.
  • 33 Department of Pathology, University of Miami Miller School of Medicine, Miami, Florida, USA.
  • 34 Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA.
  • 35 Department of Pathology and Laboratory Medicine, Baylor Scott & White Medical Center, Temple, Texas, USA.
  • 36 Department of Medicine - Infectious Disease, Denver Health & Hospital Authority, Denver, Colorado, USA.
  • 37 Department of Pathology and Laboratory Medicine, The University of Texas Health Science Center at Houston, Houston, Texas, USA.
  • 38 Division of Infectious Diseases, LSU-Ochsner Medical Center, Shreveport, Louisiana, USA.
  • 39 Albany Medical Center, Albany, New York, USA.
  • 40 Department of Medical Laboratory Science, Marquette University, Milwaukee, Wisconsin, USA.
  • 41 Division of Infectious Diseases, Hartford Hospital, Hartford, Connecticut, USA.
PMID: 41869812 DOI: 10.1128/spectrum.03289-25
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.

Keywords

Acinetobacter; CRAB; meropenem; sulbactam-durlobactam.

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