Drug-resistant Campylobacter persists in poultry
New research conducted now suggests that the ban on the
use of fluoroquinolone to treat Campylobacter in humans may not be as effective
The fluoroquinolone class of antibiotics is commonly used by doctors treat
food poisoning caused by Campylobacter
. However, poultry farmers began using
fluoroquinolones to treat respiratory disease in flocks, resulting in the drugs
being less effective in people.
Due to these concerns, in 2005, the FDA banned the use of these drugs in
poultry. However, a new study suggests that the ban may not be enough to fix the
A team of Johns Hopkins researchers made weekly trips to Baltimore
supermarkets for 20 weeks in 2004 and 15 weeks in 2006. Each week, they bought
chicken from five different producers: three producers had never used any
antibiotics; two were major conventional producers that declared they had ceased
all use of fluoroquinolones in 2002. The scientists tested one piece of chicken
from each package for Campylobacter, confirmed the bacterium's identity using
DNA analysis, then tested for antibiotic resistance using the minimal inhibitory
The bacteria from conventional chicken were more likely to be
fluoroquinolone-resistant than those from antibiotic-free products. The
researchers compared each poultry producer to every other producer in a
pair-wise fashion. In both 2004 and 2006, this statistical analysis showed that
the Campylobacter strains from the conventionally produced chicken were more
likely to be resistant than the strains from antibiotic-free samples.
In addition, between 2004 and 2006, the proportion of antibiotic-resistant
bacteria on the conventionally produced chicken showed no significant change,
indicating that the prevalence of fluoroquinolone-resistant Campylobacter was
not decreasing in chicken from these producers, even after four years.
Bacteria may reappear
Results suggest that once antibiotic-resistant bacteria have developed,
they may show up on grocery store shelves long after drug use stops. The authors
note that they could not verify claims of voluntary fluoroquinolone prohibition
because poultry producers are not required to report their use of drugs in food
animals to regulatory agencies.
Other studies have shown that resistant bacteria can linger in poultry
farms' water distribution and ventilation systems and in reused litter. The
authors state that additional interventions, such as requiring thorough
disinfection and regular litter changing in poultry houses, may be necessary to
reduce the public health burden of fluoroquinolone-resistant
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