title: Use of the E test for methicillin sensitivity testing.
abstract: Performance of the E test for methicillin sensitivity testing was investigated using 21 methicillin-resistant and 28 methicillin-sensitive staphylococci. Thirty of the strains had previously given equivocal results with a strip diffusion method. The E test performed well with Mueller-Hinton agar plates incubated at 30 degrees C for 24 h but only after supplementation with 5% NaCl. Testing on agar without salt was necessary for the recognition of methicillin resistance in one strain. We recommend a breakpoint of 4 mg/L and heavy inocula. The E test can be controlled by testing a control strain on the same plate.
authors.affiliation: Microbiology Department, St Mary's Hospital, London, UK.
authors.forename: G E
authors.initials: GE
authors.lastname: Bignardi
authors.forename: U
authors.initials: U
authors.lastname: Riley
authors.forename: C S
authors.initials: CS
authors.lastname: Easmon
mesh_terms: D003470:Culture Media; D004058:Diffusion; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests / Q000379:methods / Q000592:standards; D011934:Reagent Strips; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D003470:Culture Media; D011934:Reagent Strips; D001618:beta-Lactamases