Poultry resistant to antibiotics analysed

08-03-2007 | |

Researchers at the University of Georgia (US) have found that the use of antibiotics on poultry farms will do little to reduce bacteria that have the potential to threaten human health.

Dr. Margie Lee, professor in the UGA College of Veterinary Medicine, and her colleagues studied droppings from more than 140,000 birds, and saw that chickens raised on antibiotic-free farms, as well as those raised under pristine laboratory conditions have high levels of bacteria that are resistant to common antibiotics. In other words, poultry come to a farm harbouring resistant bacteria, possibly acquired as they were developing in their eggs.
What this means is that the resistances don’t necessarily come from antibiotic use in the birds, so banning antibiotic use on the farm isn’t going to help.
Bacteria swap genes relatively easily, and Lee explained that the concern is that drug resistance genes from bacteria that infect poultry could be passed on to bacteria that cause human illness. With these resistance genes, human bacterial illness could become harder to treat. These concerns led the European Union to ban the use of antibiotics for growth promotion in chickens in 2006. In 2005, the US Food and Drug Administration banned the use of the drug Baytril (the brand name for enrofloxacin, a fluoroquinolone antibiotic) in poultry, citing concerns that it could lead to resistance in human antibiotics such as Cipro, also a fluoroquinolone.
“They banned Baytril in 2005, and if you look at Baytril resistance in campylobacter now it’s essentially unchanged,” Lee said. Several advocacy groups are pushing for a more comprehensive animal antibiotic ban in the United States, but Lee said her research plus the evidence from the Baytril ban suggests that approach won’t help.

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