Abstract: 377 isolates recovered from diseased chickens in northern region of Henan province from the year 2005 to 2007, which were conformed as escherichia coli strains by the biochemical test, were tested for antimicrobial susceptibility. All isolates displayed high resistance against FQs. The rates of resistance against enrofloxacin, ciprofloxacin, norfloxacin were 94.9%, 93.9%, 94.9%, respectively. 235 isolates which displayed high resistance against enrofloxacin (MIC>32 μg/ml) were further screened for the presence of the qnr genes using a PCRbased strategy. The results showed that there was only one strain in which qnrlike genes was positive among these detected strains. This qnrlike gene was named qnrA after sequencing analysis.

Key words: escherichia coli;  FQs; antimicrobial resistance; qnr gene