Flumequine, a fluoroquinolone in disguise

Abstract

AbstractFluoroquinolone resistance inE. coliisolates from livestock in Europe remains high even though the EMA restricted fluoroquinolone use in animals. However, flumequine, a quinolone similar to fluoroquinolones, is still used in livestock in the Netherland, Belgium, Greece or France. Therefore, we investigated whether flumequine selects for the same resistance mechanisms inE. coli.To accomplish this, we investigated and enumerated resistant and non-resistantE. coliisolates obtained from caecal fermentation assays and from broilers exposed to different concentrations of flumequine and enrofloxacin.Flumequine usage leads to approximately 3-fold increase of resistantE. coliin the caecal fermentation, comparable with enrofloxacin. Afterin vitroexposure to flumequine and enrofloxacin we detected the same SNPs (S83L, D87G) ingyrA. Furthermore, the same resistance-causing SNPs were found in phenotypic resistantE. coliisolates from broilers treated with enrofloxacin and flumequine.Flumequine induces similar resistance mechanisms as enrofloxacin and restriction for use should be the same.