title: Detection of ampicillin resistance in Enterococcus spp. by disk diffusion and two commercial automated systems.
abstract: A total of 154 Enterococcus faecium and 48 Enterococcus faecalis isolates, 55% of which were ampicillin-resistant, were used to evaluate two commonly used automated systems, Vitek's GPS-TA card (bioMérieux, USA) and MicroScan's POS MIC Type 6 panel (Baxter Health-care, USA), and the NCCLS disk diffusion method for the detection of ampicillin resistance. MicroScan panels were read by the Walk/Away system and by visual inspection. The results were as follows: disk diffusion, 100% sensitive and specific; Vitek, 100% sensitive and 95% specific; and MicroScan, when read by the Walk/Away, 85% sensitive and 98% specific. When MicroScan was interpreted by visual inspection, however, sensitivity increased to 96%.
authors.affiliation: Princess Margaret Hospital, University of Toronto, Ontario, Canada.
authors.forename: B M
authors.initials: BM
authors.lastname: Willey
authors.forename: B N
authors.initials: BN
authors.lastname: Kreiswirth
authors.forename: G
authors.initials: G
authors.lastname: Williams
authors.forename: D E
authors.initials: DE
authors.lastname: Low
mesh_terms: D000668:Ampicillin Resistance; D013293:Enterococcus faecalis / Q000187:drug effects*; D016984:Enterococcus faecium / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*