title: Quality control ranges for testing broth microdilution susceptibility of Flavobacterium columnare and F. psychrophilum to nine antimicrobials.
abstract: A multi-laboratory broth microdilution method trial was performed to standardize the specialized test conditions required for the fish pathogens Flavobacterium columnare and F. psychrophilum. Nine laboratories tested the quality control (QC) strains Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 against 10 antimicrobials (ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, ormetoprim/sulfadimethoxine, oxolinic acid, oxytetracycline, and trimethoprim/sulfamethoxazole) in diluted (4 g l-1) cation-adjusted Mueller-Hinton broth incubated at 28 and 18°C for 44-48 and 92-96 h, respectively. QC ranges were set for 9 of the 10 antimicrobials. Most of the minimal inhibitory concentration (MIC) distributions (16 of 18, 9 drugs at both temperatures) for A. salmonicida ATCC 33658 were centered on a single median MIC ± 1 two-fold drug dilution resulting in a QC range that spanned 3 dilutions. More of the E. coli ATCC 25922 MIC distributions (7 of 16) were centered between 2 MIC dilutions requiring a QC range that spanned 4 dilutions. A QC range could not be determined for E. coli ATCC 25922 against 2 antimicrobials at the low temperature. These data and their associated QC ranges have been approved by the Clinical and Laboratory Standards Institute (CLSI), and will be included in the next edition of the CLSI M49-A Guideline. This method represents the first standardized reference method for testing fish pathogenic Flavobacterium spp.
authors: Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland 20708, USA. charles.gieseker@fda.hhs.gov
authors: Charles M
authors: CM
authors: Gieseker
authors: Tamara D
authors: TD
authors: Mayer
authors: Tina C
authors: TC
authors: Crosby
authors: Jeremy
authors: J
authors: Carson
authors: Inger
authors: I
authors: Dalsgaard
authors: Ahmed M
authors: AM
authors: Darwish
authors: Patricia S
authors: PS
authors: Gaunt
authors: Dana X
authors: DX
authors: Gao
authors: Hui-Min
authors: HM
authors: Hsu
authors: Tsang L
authors: TL
authors: Lin
authors: J Lindsay
authors: JL
authors: Oaks
authors: Melissa
authors: M
authors: Pyecroft
authors: Charlene
authors: C
authors: Teitzel
authors: Temdoung
authors: T
authors: Somsiri
authors: Ching C
authors: CC
authors: Wu
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005417:Flavobacterium / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000900:Anti-Bacterial Agents