Organic farming reduces resistance of bacteria to antibiotics, study finds

Poultry farmers who adopt organic practices and stop giving their birds antibiotics significantly reduce the resistance of bacteria to antibiotics in their flocks, according to a study released Wednesday.

Public health experts have become increasingly concerned about germs becoming resistant to many commonly used antibiotics. In fact, an outbreak of salmonella currently occurring is being caused by a resistant strain of the bacteria traced back to ground turkey.

In the new study, published in the journal Environmental Health Perspectives, Amy Sapkota of the University of Maryland School of Public Health and colleagues studied 10 conventional farms and 10 farms that had recently become organic in 2008. They tested for the presence of a bacteria known as enterococci in poultry litter, feed and water and for whether the organisms were resistant to 17 commonly used drugs.

All the farms tested positive for the bacteria. But the farms that had recently become organic had significantly lower levels of resistance. For example, 67 percent of enterococcus faecalis from conventional farms were resistant to the drug erythromycin compared to 18 percent of the organisms from the organic farms. Forty-two percent of the bacteria from conventional farms were resistant to multiple drugs, compared to only 10 percent from the organic farms.

“We initially hypothesized that we would see some differences in on-farm levels of antibiotic-resistant enterococci when poultry farms transitioned to organic practices,” Sapkota said. “But we were surprised to see that the differences were so significant across several different classes of antibiotics even in the very first flock that was produced after the transition to organic standards.”

Farm industry officials have long argued that antibiotics are extremely important to protecting the health of farm animals and keeping the food supply safe.