Detection of Florfenicol Resistance Genes inEscherichia coliIsolated from Sick Chickens

Abstract
Florfenicol is an antibiotic approved for veterinary use in cattle in the United States in 1996. Although this drug is not used in poultry, we have detected resistance to florfenicol in clinical isolates of avianEscherichia coli. Molecular typing demonstrated that the florfenicol resistance gene,flo, was independently acquired and is plasmid encoded.