title: Evaluation of the VITEK 2 AST-N111 card for detection of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli, Klebsiella pneumoniae, and Klebsiella oxytoca compared to ESBL Etests and combination disk methods.
abstract: The VITEK 2 AST-N111 card was evaluated for detection of extended-spectrum beta-lactamases (ESBLs) by testing 51 ESBL positive and 50 ESBL negative isolates of E. coli, K. pneumoniae, and K. oxytoca. The occurrence of beta-lactamase genes was confirmed by PCR and sequencing. The advanced expert system (AES) of the VITEK 2 system achieved sensitivity and specificity values of 100% and 96.0%, respectively. The ESBL test of the VITEK 2 AST-N111 card showed a sensitivity of 92.1% and a specificity of 90.0%. Contradictory results obtained with the two VITEK 2 tools could be clarified by combination disk tests in nine of 11 isolates. The combined use of AES and ESBL tests of the AST-N111 card in association with combination disk tests in case of contradictory results seems to be a reliable method for ESBL detection.
authors.affiliation: Institute of Hygiene and Microbiology, University of Wuerzburg, Josef-Schneider-Str. 2 / E1, 97080, Wuerzburg, Germany. gvalenza@hygiene.uni-wuerzburg.de
authors.forename: G
authors.initials: G
authors.lastname: Valenza
authors.forename: S
authors.initials: S
authors.lastname: Müller
authors.forename: C
authors.initials: C
authors.lastname: Schmitt
authors.forename: D
authors.initials: D
authors.lastname: Turnwald
authors.forename: T-T
authors.initials: TT
authors.lastname: Lam
authors.forename: M
authors.initials: M
authors.lastname: Frosch
authors.forename: M
authors.initials: M
authors.lastname: Abele-Horn
authors.forename: Y
authors.initials: Y
authors.lastname: Pfeifer
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D041121:Klebsiella oxytoca / Q000201:enzymology* / Q000235:genetics; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D001618:beta-Lactamases