title: In vitro susceptibility of characterized β-lactamase-producing strains tested with avibactam combinations.
abstract: Avibactam, a broad-spectrum β-lactamase inhibitor, was tested with ceftazidime, ceftaroline, or aztreonam against 57 well-characterized Gram-negative strains producing β-lactamases from all molecular classes. Most strains were nonsusceptible to the β-lactams alone. Against AmpC-, extended-spectrum β-lactamase (ESBL)-, and KPC-producing Enterobacteriaceae or Pseudomonas aeruginosa, avibactam lowered ceftazidime, ceftaroline, or aztreonam MICs up to 2,048-fold, to ≤4 μg/ml. Aztreonam-avibactam MICs against a VIM-1 metallo-β-lactamase-producing Enterobacter cloacae and a VIM-1/KPC-3-producing Escherichia coli isolate were 0.12 and 8 μg/ml, respectively.
authors.affiliation: Indiana University, Bloomington, Indiana, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Li
authors.affiliation: Indiana University, Bloomington, Indiana, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Estabrook
authors.affiliation: Lahey Hospital and Medical Center, Burlington, Massachusetts, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Jacoby
authors.affiliation: AstraZeneca, Waltham, Massachusetts, USA.
authors.forename: Wright W
authors.initials: WW
authors.lastname: Nichols
authors.affiliation: AstraZeneca, Waltham, Massachusetts, USA.
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Testa
authors.affiliation: Indiana University, Bloomington, Indiana, USA karbush@indiana.edu.
authors.forename: Karen
authors.initials: K
authors.lastname: Bush
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D053961:Azabicyclo Compounds / Q000494:pharmacology*; D004359:Drug Therapy, Combination / Q000379:methods; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D065093:beta-Lactamase Inhibitors / Q000494:pharmacology; D047090:beta-Lactams / Q000037:antagonists & inhibitors*
chemical_list: D000900:Anti-Bacterial Agents; D053961:Azabicyclo Compounds; D065093:beta-Lactamase Inhibitors; D047090:beta-Lactams; C543519:avibactam