Effect of enrofloxacin administration on excretion of Salmonella enteritidis by experimentally infected chickens and on quinolone resistance of theirEscherichia coli flora

Chickens which had been experimentally-infected with a strain of Salmonella enteritidis and treated by administration of enrofloxacin at commercially recommended concentrations in the drinking water, virtually. eliminated thi s organism from the alimentary tract. However, an initially quinolone-sensi tive Escherichia coli flora present in the birds' faeces was rapidly replac ed by a quinolone-resistant flora which persisted after withdrawal of the m edication. Resistance to quinolone in the form of nalidixic acid was transd ucible from a strain of S. typhimurium to S. enteritidis with bacteriophage P22.