Activity of ampicillin-sulbactam, sulbactam-durlobactam, and comparators against Acinetobacter baumannii-calcoaceticus complex strains isolated from respiratory and bloodstream sources: results from ACNBio study

Ecem Buyukyanbolu, 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, Albert Einstein College of Medicine, Montefiore Medical Center, New York, 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, Harbor-UCLA Medical Center, Torrance, California, 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.
Jamie Marino, Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, USA.
Lars F. Westblade, Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, New York, USA.
A Brian Mochon, Banner Health, Phoenix, Arizona, USA.
Navaneeth Narayanan, Department of Pharmacy Practice and Administration, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey, USA.
Thomas J. Kirn, Department of Pathology & Laboratory Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, 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, Johns Hopkins University School of Medicine, Baltimore, Maryland, 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 Pharmacy, Jackson Health System, Miami, Florida, USA.
et al

Affiliations

Advocate Lutheran General Hospital

Abstract

Infections caused by carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (ABC) are associated with high mortality rates and limited treatment options. This study aims to evaluate the in vitro activity of clinically utilized antimicrobials against a contemporary collection of ABC isolates with a predominant carbapenem-resistant phenotype. Geographically dispersed US medical centers (n = 22) provided non-duplicate respiratory and bloodstream ABC isolates for surveillance testing. Antimicrobial susceptibility testing was conducted by broth microdilution and interpreted according to Clinical & Laboratory Standards Institute (CLSI) and Food and Drug Administration (FDA) breakpoints. ABC isolates (n = 523) from respiratory tract (74.4%) and blood (25.6%) sources were recovered from patients (2023-2024). Forty percent were obtained from intensive care unit patients. Carbapenem non-susceptibility was observed in 76.9% of isolates and was more common among respiratory tract cultures. The addition of durlobactam to sulbactam decreased the MIC90 by three-doubling dilutions from 32 to 4 µg/mL, increasing the susceptibility rate to 96.9% from 33.8%. Genome sequencing of sulbactam-durlobactam non-susceptible isolates (16/523; n = 3.1%) revealed MBL and non-enzymatic resistance mechanisms. Cefiderocol inhibited 93.5% and 76.1% of isolates at CLSI and FDA susceptible breakpoints, respectively. Minocycline susceptibility was50/90 were 1/2 and 0.5/1 µg/mL, respectively. Sulbactam-durlobactam displayed high activity against sulbactam (95.4%), carbapenem (96.3%), and cefiderocol (95.2%) non-susceptible isolates. Susceptibility rates of clinically utilized antimicrobials against a US collection of ABC isolates ranged from 23% to 97%, with meropenem displaying the lowest rate and sulbactam-durlobactam demonstrating the highest overall rate. Sulbactam-durlobactam activity was preserved against sulbactam, carbapenem, and cefiderocol non-susceptible isolates among respiratory tract and bloodstream isolates.

Document Type

Article

PubMed ID

40673757

Link to Full Text

 

Share

COinS