06/03/2011 05:03 pm ET Updated Aug 03, 2011

How Decades Of Farm Animal Antibiotics Led To Deadly Superbugs

... Even though Levy had added only tetracycline to the feed, his chickens had somehow developed what scientists now call "multi-drug resistance" to a host of antibiotics that play important roles in treating infections in people. More frightening, although none of the members of the farm family tending the flock were taking antibiotics, they, too, soon began excreting drug-resistant strains of E. coli.

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