title: Epidemiological cut-off values for Flavobacterium psychrophilum MIC data generated by a standard test protocol.
abstract: Epidemiological cut-off values were developed for application to antibiotic susceptibility data for Flavobacterium psychrophilum generated by standard CLSI test protocols. The MIC values for ten antibiotic agents against Flavobacterium psychrophilum were determined in two laboratories. For five antibiotics, the data sets were of sufficient quality and quantity to allow the setting of valid epidemiological cut-off values. For these agents, the cut-off values, calculated by the application of the statistically based normalized resistance interpretation method, were ≤16 mg L(-1) for erythromycin, ≤2 mg L(-1) for florfenicol, ≤0.025 mg L(-1) for oxolinic acid (OXO), ≤0.125 mg L(-1) for oxytetracycline and ≤20 (1/19) mg L(-1) for trimethoprim/sulphamethoxazole. For ampicillin and amoxicillin, the majority of putative wild-type observations were 'off scale', and therefore, statistically valid cut-off values could not be calculated. For ormetoprim/sulphadimethoxine, the data were excessively diverse and a valid cut-off could not be determined. For flumequine, the putative wild-type data were extremely skewed, and for enrofloxacin, there was inadequate separation in the MIC values for putative wild-type and non-wild-type strains. It is argued that the adoption of OXO as a class representative for the quinolone group would be a valid method of determining susceptibilities to these agents.
authors.affiliation: Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland.
authors.forename: P
authors.initials: P
authors.lastname: Smith
authors.affiliation: Merck Animal Health, Summit, NJ, USA.
authors.forename: R
authors.initials: R
authors.lastname: Endris
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Kronvall
authors.affiliation: MSD Animal Health Innovation, GmbH Zur Propstei, Schwabenheim, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Thomas
authors.affiliation: CEFAS Weymouth Laboratory, Weymouth, Dorset, UK.
authors.forename: D
authors.initials: D
authors.lastname: Verner-Jeffreys
authors.affiliation: MSD Animal Health Innovation, GmbH Zur Propstei, Schwabenheim, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Wilhelm
authors.affiliation: National Veterinary Institute, Technical University of Denmark, Frederiksburg, Denmark.
authors.forename: I
authors.initials: I
authors.lastname: Dalsgaard
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005393:Fish Diseases / Q000382:microbiology*; D045826:Flavobacteriaceae Infections / Q000453:epidemiology / Q000662:veterinary*; D005417:Flavobacterium / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D015203:Reproducibility of Results
chemical_list: D000900:Anti-Bacterial Agents
keywords: CLSI protocols; Flavobacterium psychrophilum; MIC; VET03/04-S2; epidemiological cut-off values; normalized resistance interpretation