title: Comparative evaluation of tigecycline susceptibility testing methods for expanded-spectrum cephalosporin- and carbapenem-resistant gram-negative pathogens.
abstract: We evaluated the Vitek2, Etest, and MIC Test Strip (MTS) methods of tigecycline susceptibility testing with 241 expanded-spectrum cephalosporin-resistant and/or carbapenem-resistant Enterobacteriaceae and Acinetobacter baumannii clinical isolates by using dry-form broth microdilution (BMD) as the reference method. The MIC(50/90)s were as follows: BMD, 1/4 μg/ml; Vitek2, 4/≥8 μg/ml; Etest, 2/4 μg/ml; MTS, 0.5/2 μg/ml. Vitek2 produced 9.1/21.2% major errors, Etest produced 0.4/0.8% major errors, and MTS produced no major errors but 0.4/3.3% very major errors (FDA/EUCAST breakpoints). Vitek2 tigecycline results require confirmation by BMD or Etest for multidrug-resistant pathogens.
authors.affiliation: Department of Microbiology, Tzaneio General Hospital, Piraeus, Greece.
authors.forename: Olympia
authors.initials: O
authors.lastname: Zarkotou
authors.forename: Spyros
authors.initials: S
authors.lastname: Pournaras
authors.forename: George
authors.initials: G
authors.lastname: Altouvas
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Pitiriga
authors.forename: Maria
authors.initials: M
authors.lastname: Tziraki
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Mamali
authors.forename: Katerina
authors.initials: K
authors.lastname: Themeli-Digalaki
authors.forename: Athanassios
authors.initials: A
authors.lastname: Tsakris
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D000078304:Tigecycline; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D002511:Cephalosporins; D000078304:Tigecycline; D008911:Minocycline