P-054. Prevalence of Ciprofloxacin Resistance in Thermophilic Campylobacters from Turkeys in North Carolina before and after the Fluoroquinolone Ban

W. Gu, M. Islam, R. Siletzky, S. Kathariou;
North Carolina State Univ., Raleigh, NC.

Campylobacter jejuni and C. coli from conventionally grown turkeys have been frequently reported to be resistant to fluoroquinolones. To reduce the possible contribution of fluoroquinolone resistance in Campylobacter in poultry, use of enrofloxacin (trade name, Baytril) was banned in 2005. However, the impact of this ban on fluoroquinolone resistance in thermophilic Campylobacters from turkeys has not been rigorously evaluated yet. In this study, we investigated prevalence of resistance to ciprofloxacin and nalidixic acid among 1248 isolates of Campylobacter (201 C. jejuni and 1047 C. coli) derived from the ceca of young turkeys (10 days to 6 weeks of age). The isolates were derived from different flocks and farms, representing three different integrators, from 2002 to 2007. Resistance to ciprofloxacin and nalidixic acid was highly prevalent (464/593, 78.25%) among isolates from 2002 to 2004, and was even more prevalent among isolates from 2006 and 2007, the two years subsequent to the ban (504/533, 94.56%). Of isolates obtained in 2005, 82.79% (101/122) were resistant to the antibiotics. To determine if the ban had an effect on the degree of resistance to fluoroquinolones and/or other antimicrobials, representative isolates from each surveyed flock of each year were chosen for determination of the minimum inhibitory concentrations (MICs) of ciprofloxacin, tetracycline, and kanamycin using the agar dilution method. Ciprofloxacin MIC determinations suggested that there was no obvious difference in MIC distribution before and after the enrofloxacin ban. Our results suggest that there was no detectable decrease in prevalence of fluoroquinolone resistance among turkey-derived campylobacters within the surveyed two-year period following the enrofloxacin ban. Instead, and for reasons that remain unknown, prevalence of resistance was higher among isolates from 2006 and 2007 than among those from 2002-2004. Continued surveys are needed to further evaluate the potential impact of the ban on resistance of campylobacters from turkeys to fluoroquinolones and other antibiotics.