Thursday, November 29, 2012

Pork: Contaminated with Antibiotic Resistant Bacteria?
Here is a study published in Consumer Reports that looked at the presence of antibiotic resistant bacteria in pork. They tested 198 samples of ground pork and pork chops, all consumer products, and found that 69% were contaminated with Yersinia enterocolitica, 11% were contaminated with Enterococcus, 7% were contaminated with Staphylococcus aureus and 4% were contaminated with Salmonella.

Of the whopping 69% of products contaminated with Yersinia enterocolitica, 39% were resistant to 2-3 antibiotics. Sixty-four percent of the Staphylococcus aureus isolates were resistant to 2-4 antibiotics and 38% of the Salmonella isolates were resistant to 5 antibiotics.

These findings highlight the issue of antibiotic use in the food industry driving antibiotic resistance in general. As antibiotics are used in a population of animals (pigs, for instance), antibiotic susceptible bacteria are killed off (thus 'selecting out' resistant bacteria); these bacteria are then shed into the environment, contaminate fertilizer and can contaminate food products such as the pork noted in this study. Humans then can become colonized or sick when they come in contact with these organisms. A person who ingests undercooked pork contaminated with bacteria such as Yersinia enterocolitica could develop a severe diarrheal illness that would be more difficult to treat as the organism is already resistant to multiple antibiotics.

This report highlights key things consumers can do to protect themselves, such as ensuring meat is cooked appropriately (thus killing any bacterial contaminants), keeping raw meat separate from other foods and good hand washing.

This report is a disturbing real-time reminder that non-human antibiotic use is an important component of the current antibiotic resistance crisis; this is especially important when one considers that approximately 80% of all antibiotics used in the United States are used in food-production animals. Efforts to combat antibiotic resistance must account for the large percentage of antibiotic use in the food industry, and true solutions to this problem will require coordinated efforts across multiple disciplines.


  1. for a little balance to the CR story check out this response from an MD on the credibility of the testing done-

    1. Thanks for the post! Interesting commentary on the story. Some quick comments: antibiotics used for animals do have implications for drug resistance in humans even if the specific antibiotics that are used aren't used in both groups-for instance, drug resistance often emerges to an entire class of antibiotics (such as tetracyclines)-so it doesn't matter that the specific drug (chlortetracycline versus tetracycline, for instance) isn't the same-the antibiotic resistance that emerges in animals to these drugs more often than not will confer resistance to that class of antibiotics if transferred to humans. Antibiotic resistance in one class also has implications for drug resistance to other classes of antibiotics-for instance, some resistance mechanisms that cause macrolide resistance also confer lincosamide resistance, for instance.

      Also-don't think the analogy between promoting health in children with vaccines and promoting growth in animals with antibiotics is a good one; a true parallel would be using antibiotics to promote growth in humans which is not standard practice by any means! Although there has been recent data suggesting a link between antibiotic use and the obesity epidemic!

      Thanks again for the post!