Organic farms harbor far less antibiotic-resistant bacteria

Dominika Osmolska Psy.D.'s picture

As if there weren’t enough good reasons to purchase your food from organic farms, here is another encouraging tidbit from researchers at University of Maryland’s Institute for Applied Environmental Health: organic farms turn out to harbor significantly less antibiotic-resistant bacteria than conventional farms.

Given the latest food contamination headlines, including the ground turkey Salmonella scare, and the emergence of an antibiotic-resistant Salmonella strain, consumers are once again confronted with the perils of conventional farming, both animal and produce. Antibiotic-resistant strains of bacteria and other pathogens are particularly worrisome because once a pathogen sickens people, it makes it much more difficult to treat than it would have been in the past.

But even without making us sick, conventionally raised meat which is pumped full of such antibiotics makes it more likely that we will develop that kind of resistance. Then, when need arises and we need to use antibiotics for some health condition that may arise in the future, they may prove ineffective, putting our lives at risk.

New research, however, is showing that the fix may be easier than we think: scientists at the University of Maryland have demonstrated that going organic, or at least removing antibiotics from large poultry farms, means a huge drop in antibiotic resistance for several types of bacteria.

The team zeroed in on enterococci bacteria, a pathogen that hangs out in our intestines and causes many common urinary tract and surgical wound infections. The investigators studied large-scale poultry farms in the mid-Atlantic region – ten of them newly organic and ten non-organic – to find if these bacteria were present and to check the enterococci's resistance to 17 common antimicrobials.


"We chose to study enterococci because these microorganisms are found in all poultry, including poultry on both organic and conventional farms. The enterococci are also notable opportunistic pathogens in human patients staying in hospitals," study leader Amy Sapkota, an assistant professor with the Institute, said.

What they found was that the just-turned-organic farms had a significantly lower presence of antibiotic-resistant enterococci in their poultry feed, litter and water. And the bacteria the farms did have were easier to beat. Just 18 percent of the Enterococcus faecalis in the newly organic poultry farms, for example, were resistant to an antibiotic that treats pneumonia, whooping cough and bronchitis, compared to 67 percent on the non-organic farms. The conventional farms also had much higher levels of multi-drug resistant bacteria, or bacteria that can be resistant to all available antibiotics. A whopping 84 percent of Enterococcus faecium from conventional farms were resistant to multiple drugs compared to only 17 percent of newly organic farms.

The study was published online Aug. 10 in the journal Environmental Health Perspectives.

“These findings show that, at least in the case of enterococci, we begin to reverse resistance on farms even among the first group of animals that are grown without antibiotics,” said Sapkota. And these findings could translate to the Salmonella that have been invading our meat recently: enterococci likes exchanging its resistance genes with other bacteria and is thus a “good model” for studying antibiotic use in farms, according to Sapkota.

Sapkota predicts that as farms increasingly adopt the organic — or at least drug-free — route we will see even greater drops in drug-resistant bacteria. “We need to look forward and see what happens over 5 years, 10 years in time,” she said.

Cutting down on the antibiotics used in farms is an incredibly good start in reducing the epidemic of antibiotic resistant bacteria from our environment. Farms, not humans, are really at the forefront of nurturing these pathogens: a shocking 80% of the antibiotics sold in the United States each year are consumed not by humans, but by cows, chickens and other domesticated animals.


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