Drug-Resistant Staph Linked to Animal Antibiotics.
Because both tetracycline and penicillins are commonly administered to food animals, the study finds that it is likely that the use of these drugs in livestock gave this Staph bacteria the exposure it needed to develop resistance to these drugs. In 2010, Tetracycline - used to promote growth and prevent the spread of disease - comprised over 42 percent of all antibiotics administered to food-producing animals in the United States. That year 12,328,520 pounds of the drug were given to animals, while just over 100,000 pounds of the drug are sold for human use. And while over 1.9 million pounds of penicillin were sold for animal use in 2010, approximately 1.5 million pounds are distributed for human use. Both of these drugs are crucial for treating human Staph infections, says Dr. Lance Price, lead author of the study and Director of TGen's Center for Food Microbiology and Environmental Health. "Methacyline's a really good antibiotic for treating these kinds of infections," he told Food Safety News in an interview. "But a substantial portion of the population is allergic to penicillin and they need alternative drugs like tetracycline. But 69% of the staph we see is resistant to tetracycline." Price says that animal feeding operation provide the perfect setting for the growth of antibiotic-resistant bacteria. According to the Centers for Disease Control and Prevention, MRSA is easily transmitted in settings where factors it calls the "5 Cs" are present: crowding, frequent skin-to-skin contact, compromised skin (cuts or abrasions), contamination or lack of cleanliness. "A CAFO (Concentrated Animal Feeding Operation) is the place where these 5 Cs are most prevalent," says Price. "And the single worst thing you could do is add antibiotics to that environment. It's the cocktail for creating superbugs."
