July 10, 2006
Drug-resistant E. coli likely started in poultry
NEW YORK (Reuters Health) - The food-contaminating bug E.
coli -- which can cause diarrhea, urinary tract infections and
more severe illness in humans -- appears to be developing
resistance to antibiotics called fluoroquinolones in chickens,
a study shows.
The problem is arising largely because of antibiotic
treatment of the animals, which forces the microbes to mutate
and become resistant. Food-borne resistant E. coli can then be
transmitted to humans.
Action to interrupt the transmission of resistant bacteria
from animals to humans may become necessary, the researchers
say. Such measures could include "limiting antimicrobial use in
food animals, adopting more hygienic food-processing and
distribution practices, irradiating food, and improving kitchen
In the late 1990s, Dr. James R. Johnson of the University
of Minnesota in Minneapolis and colleagues obtained E. coli
from 35 blood samples and 33 fecal samples from patients with
food poisoning seen at a hospital in Barcelona. The
investigators also evaluated 49 fecal specimens from chickens
at three slaughterhouses in the area.
They found that 30 of the human specimens and 30 of the
chicken specimens were resistant to Cipro, a type of
fluoroquinolone antibiotic, according to their report in The
Journal of Infectious Diseases.
Resistant human isolates resembled the resistant chicken
isolates in terms of virulence and their DNA sequence.
"These data provide the strongest molecular evidence
available to date for a food (specifically chicken) source for
potentially pathogenic fluoroquinolone-resistant E. coli in
humans," Johnson and his team write.
They emphasize that even though the resistant organisms
from humans and chickens were less virulent than
antibiotic-susceptible human E. coli isolates, "they are not
benign." The resistant isolates are still capable of causing
blood poisoning and acute urinary tract infections in humans.
Once these findings are confirmed in other studies, the
researchers conclude, they will "provide a compelling rationale
for efforts to eliminate such organisms from the food supply."
SOURCE: Journal of Infectious Diseases, July 1, 2006.