title: Reproducibility of the microdilution checkerboard method for antibiotic synergy.
abstract: We assessed the reproducibility of the microdilution checkerboard method for measuring antibiotic synergy. Five strains of Pseudomonas aeruginosa were tested with four antibiotic combinations by using 10 replicates each. Twenty-five percent of replicate sets gave discordant classification results (i.e., a 7:3 or worse split in categorization). Determination of the individual MICs of each antibiotic alone was excellent; all 10 replicates were within 1 twofold dilution for 95% of the 80 sets of 10 replicates. The microdilution checkerboard method either should not be used or should be used with at least five replicates per determination, with > or = 80% agreement among the replicates required for classification.
authors: Department of Pathology and Laboratory Medicine, University of Florida, Gainesville.
authors: K H
authors: KH
authors: Rand
authors: H J
authors: HJ
authors: Houck
authors: P
authors: P
authors: Brown
authors: D
authors: D
authors: Bennett
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004357:Drug Synergism; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents