- 1Food
Animal Health Research Program, Ohio Agricultural Research and
Development Center, Department of Veterinary Preventive Medicine, The
Ohio State University , Wooster, Ohio.
Abstract
Poultry
is a major source of Campylobacter, which can cause foodborne bacterial
gastroenteritis in humans. Additionally, poultry-associated
Campylobacter can develop resistance to important antimicrobials, which
increases the risk to public health. While broiler chickens have been
the focus of many studies, the emergence of antimicrobial-resistant
Campylobacter on layer farms has not received equal attention. However,
the growing popularity of cage-free and organic layer farming
necessitates a closer assessment of (1) the impact of these farming
practices on the emergence of antimicrobial-resistant Campylobacter and
(2) layers as a potential source for the transmission of these
pathogens. Here, we showed that the prevalence of Campylobacter on
organic and conventional layer farms was statistically similar
(p > 0.05). However, the average number of Campylobacter
jejuni-positive organically grown hens was lower (p < 0.05) in
comparison to conventionally grown hens. Campylobacter isolated from
both production systems carried antimicrobial resistance genes. The
tet(O) and cmeB were the most frequently detected genes, while the
occurrence of aph-3-1 and blaOXA-61 was significantly lower
(p < 0.05). Farming practices appeared to have an effect on the
antimicrobial resistance phenotype, because the isolates from
organically grown hens on two farms (OF-2 and OF-3) exhibited
significantly lower resistance (p < 0.05) to ciprofloxacin,
erythromycin, and tylosin. However, on one of the sampled organic farms
(OF-1), a relatively high number of antimicrobial-resistant
Campylobacter were isolated. We conclude that organic farming
can potentially impact the emergence of antimicrobial-resistant
Campylobacter. Nevertheless, this impact should be regularly monitored
to avoid potential relapses.
KEYWORDS:
C. coli; C. jejuni; Campylobacter; antimicrobial resistance; food safety; layer chickens; organic farms
