A microbiological assay for determining sarafloxacin and oxolinic acid concentrations in Atlantic salmon plasma

: A microbiological assay was developed to quantify the concentrations of the quinolone antibiotics sarafloxacin and oxolinic acid in Atlantic salmon (Salmo salar) plasma. The assay was a modification of the Association of Official Analytical Chemists (AOAC) method for antibiotic concentrations in feeds using disk diffusion and a lawn of Vibrio anguillarum ATCC 19264 as the test organism. With these modifications, sensitivities of 0.04 microgram/mL for sarafloxacin and 0.125 micrograms/mL for oxolinic acid were obtained.