Reuters HealthMonday, July 10, 2006
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 hygiene."
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.