MicrobeWorld

An update now on a story we're been following closely about a health risk most people don't know about - farmers feeding antibiotics to healthy animals - just to spur their growth. Congress urged them this week to stop doing that because overuse of antibiotics in animals is creating new, drug-resistant strains of bacteria that can spread to humans.

CBS Evening News Anchor Katie Couric reports.

Dave Kronlage of Dyersville, Iowa told us he feeds antibiotics to his hogs before they get sick in order to accelerate growth and fend off diseases that can spread when livestock are raised in crowded conditions.

"You give it to them because you want them to be healthy," Kronlage said.

But this week on Capitol Hill critics worried giving antibiotics to livestock, unless medically necessary, may be creating dangerous, drug-resistant bacteria that can be passed on to humans.

"We would be shocked if a pediatrician ever ordered antibiotics for an entire nursery school class to keep the children from being infected," said Rep. Henry Waxman, D-Calif.