title: In vitro activity of ceftolozane-tazobactam as determined by broth dilution and agar diffusion assays against recent U.S. Escherichia coli isolates from 2010 to 2011 carrying CTX-M-type extended-spectrum β-lactamases.
abstract: Ceftolozane MIC(50)/MIC(90)s were 4/8 μg/ml when tested against 26 CTX-M-14-type-producing isolates and 64/>64 μg/ml against 219 CTX-M-15-type-producing isolates. The addition of 4 μg/ml tazobactam lowered the ceftolozane MIC50/MIC9(0)s to ≤ 0.25/0.5 μg/ml by broth microdilution and Etest. The zone diameters for the ceftolozane-tazobactam disks were 23 to 29 mm for 92.2% of the isolates.
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Estabrook
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA.
authors.forename: Brianne
authors.initials: B
authors.lastname: Bussell
authors.affiliation: Cubist Pharmaceuticals, Inc., Lexington, Massachusetts, USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Clugston
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University Bloomington, Bloomington, Indiana, USA karbush@indiana.edu.
authors.forename: Karen
authors.initials: K
authors.lastname: Bush
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000078142:Tazobactam; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C000594038:ceftolozane, tazobactam drug combination; D010397:Penicillanic Acid; D000078142:Tazobactam