P2-192 Investigation of Erythromycin-resistant Campylobacter jejuni from Turkey Farms in North Carolina

Tuesday, August 2, 2016
America's Center - St. Louis
Hannah Bolinger, North Carolina State University, Raleigh, NC
Margaret Kirchner, North Carolina State University, Raleigh, NC
Kshipra Chandrashekhar, North Carolina State University, Raleigh, NC
William Miller, U.S. Department of Agriculture-ARS, Albany, CA
Jeffrey Niedermeyer, North Carolina State University, Raleigh, NC
Donna Carver, North Carolina State University, Raleigh, NC
Sophia Kathariou, North Carolina State University, Raleigh, NC
Introduction: Campylobacter is a leading cause of bacterial foodborne illness and is often linked to contaminated poultry. Macrolides such as erythromycin are the drugs of choice when treatment is indicated.  Even though erythromycin resistance is frequent among Campylobacter coli, it remains rare in C. jejuni and was not encountered during several years of surveillance of Campylobacter from turkeys in North Carolina.  However, from 2014-2016, three North Carolina turkey flocks were found to be colonized by erythromycin-resistant (ErmR) C. jejuni strains.

Purpose: The purpose of this study was to determine the prevalence of ErmR C. jejuni in turkey farms and identify the genetic cause of the resistance.

Methods: Campylobacter spp. from turkey cecal or fecal samples and from flies in turkey farms were isolated on selective media (mCCDA), speciated via multiplex PCR, characterized for antibiotic resistance and genotyped by multilocus sequence typing (MLST).  A 23S rRNA gene fragment was amplified and sequenced to identify mutations known to associate with macrolide resistance.

Results: ErmR C. jejuni was identified in 0.53%, 0.91%, and 3.7% (since 3/2/16) of the flocks from 2015-2016, respectively.  Of the three flocks with ErmR C. jejuni, one yielded isolates with ST-1839 and another ST-7729, which was novel and differed in all seven alleles from ST-1839. Previously identified ST-1839 isolates were multidrug resistant but were erythromycin sensitive.  The ErmR C. jejuni isolates harbored the 23S rRNA mutation associated with macrolide resistance.

Significance: Although uncommon in turkey flocks, flocks colonized by ErmR C. jejuni were identified.  The presence of a macrolide resistance associated mutation in a chromosomal locus suggests the potential for dissemination to other C. jejuni via transformation. These data will enhance the currently limited knowledge regarding ErmR C. jejuni in food animals and will contribute to further surveillance on the prevalence of ErmR C. jejuni in poultry.