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Antibiotics in Food Animal Production: Pew’s Response to Raymond Op-Ed

Opinion

In his attempt to clarify the issue of antibiotic use in meat and poultry production (“Antibiotics and Animals Raised for Food: Lies, Damn Lies and Statistics,” Jan. 7), Dr. Richard Raymond confuses matters.

Most importantly, Dr. Raymond mischaracterizes the value of tetracyclines and the dangers of their overuse. The World Health Organization ranks their importance on par with macrolides (such as the “Z-Pak” antibiotic Azithromycin), fluoroquinolones and cephalosporins, which Dr. Raymond acknowledges are worth protecting. (By the way, in 2009, five times more macrolides were sold for food animal production than for treating sick people.) Yet even if doctors stop prescribing tetracycline, its widespread use on industrial farms will still pose a serious threat to our health. Bacteria often develop resistance to other classes of drugs as a direct result of their exposure to tetracyclines.

Dr. Raymond also asserts that to compare human and animal antibiotic sales more appropriately, one must exclude drugs that are not prescribed for people and, therefore, are not medically important. This changes little, however. After subtracting animal-only antibiotics from this comparison, about 70 percent of medically important antibiotics are still sold for use on industrial farms.

As to Denmark’s antibiotics policies, they have been successful. Overall antibiotic use on industrial farms is down, the prevalence of drug-resistant bacteria in animals and on meat is also down, production is up, and prices are stable.

We agree with Dr. Raymond that resistance is driven by human antibiotic use, but not exclusively. Overuse of these drugs anywhere is a threat to health everywhere, so this fight requires a 360-degree strategy that tackles antibiotic overuse in hospitals and on farms, infection control and the development of new drugs. That is why The Pew Charitable Trusts has multiple efforts underway to protect the public from resistant infections. Pew’s Antibiotics and Innovation Project is working to stimulate the development of new drugs to fight emerging superbugs. The Pew Campaign on Human Health and Industrial Farming is aimed squarely at preserving the effectiveness of antibiotics by curbing their overuse in food animal production. We oppose the use of antibiotics for growth promotion but strongly support their use to treat sick animals and to control the spread of infection in flocks or herds where disease is present. If illnesses are routinely occurring from birth through slaughter, however, then that suggests there are serious, systemic issues better solved by cleaner conditions and modified husbandry practices—not by using antibiotics as a crutch.

It is worth noting that the American Medical Association, the American Academy of Pediatrics, the Infectious Diseases Society of America, and several Nobel laureates, among many others, recognize that medically important antibiotics are being overused and misused on industrial farms at the expense of human health and that it is in the public’s interest to rein in these practices and preserve the effectiveness of these life-saving resources.

© Food Safety News
  • Richard Raymond

    We agree for the most part that antibiotics important to human health not be used as growth promoters, and the FDA also agrees and is taking steps to remove them as feed additives. We disagree about the use of the 80% number and it value in the discussion. I did not say that resistance was exclusively driven by human antibiotic use, in fact my piece calls for more aggressive restrictions on the use of Macrolides in animal husbandry. And even though 70% of antibiotics used in human medicine may also be used in animal medicine, I pointed out that some of them, like the flouroquinolones and cephalosporins are prescribed in miniscule amounts by DVMs for animal use. I would ask the PEW Charitable Trusts to please provide the scientific evidence that using ionophores in animal health contributes to superbugs such as  MRSA and VRE.  

  • Richard Raymond

    Regarding the “importance” of tetracyclines, let me just say this:
     I don’t even remember when the last time I wrote a prescription for a tetracycline was, but probably way back in the 80′s. And I do remember that the patient had to drive 100 miles to find a pharmacy that even had any in stock. That is how “important” the class is to prescribing health care providers and their patients in the US.      

  • Gail_Hansen

    Thank you for your comments. I’m glad we agree that we should stop using antibiotics to promote growth and I’m equally heartened by your points about macrolides.
     
    As for tetracyclines, I would not completely dismiss the anecdotal evidence of your experience, but I put great stock in the evidence-based characterizations of the World Health Organization, Food and Agriculture Organization, the World Organization for Animal Health, and the United States Food and Drug Administration that tetracyclines are critically important antimicrobials for human health. There were over 134,000 kgs of tetracycline sold in the U.S. in 2009 for human use (compared to 172,000 kgs of macrolides). It would be a shame to write tetras off completely just because they’ve been overused to near obsolescence by food animal producers. They remain important drugs for many people, so we should treat them as such.
     
    As to the 80 percent figure versus the 70 percent figure, both tell us that antibiotics are overused on industrial farms—and ionophore use is still symptomatic of a deeper problem (using antibiotics to mask poor production practices). That said, because ionophores are not used in human medicine, we do not support policies that would restrict their use. Even PAMTA, which you don’t appear to support, doesn’t touch ionophores. So we can agree to put ionophores aside.
     
    You ask about MRSA. I’ll point you to a study published last April by mBio, the journal of the American Society of Microbiologists. It used DNA fingerprinting for the first time to track the evolution of a superbug known as MRSA ST398, an emerging strain that appears to be adept at spreading from animals to people and from people to people. What the study found was that humans passed an antibiotic-susceptible strain of the bacteria to pigs in the Netherlands, where antibiotic use in hog production allowed that strain to become MRSA and resistant to other antibiotics. We gave pigs staph as we gave them antibiotics. They gave us MRSA ST398, which now accounts for about a quarter of MRSA infections in some parts of the Netherlands—and is spreading. In northern Denmark, hospitals have started mandatory screening of patients for MRSA ST398 and isolation of patients with confirmed cases.
     
    As for VRE, some studies looked at rates of VRE infections in countries where industrial farms used avoparcin (a member of the same glycopeptide class of antibiotics as vancomycin) and where they did not. VRE was more prevalent in the former than the latter. According to one study: “In countries using avoparcin, a glycopeptide antibiotic, as a growth promoter, vancomycin-resistant enterococci (VRE) are commonly found in the commensal flora of food animals, on meat from these animals and in the commensal flora of healthy humans despite very limited use of vancomycin in hospitals. In The Netherlands in 1996 and 1998, approximately 1500 and 1260 kg of vancomycin, respectively, was used for human therapy, whilst an estimated 80000 kg of avoparcin was used yearly in farming until 1997. By contrast, in those countries not allowing the use of avoparcin, no VRE have been detected in food animals, food of animal origin or healthy humans in the general population. Sweden banned the use of all antibiotics as growth promoters in 1986 and no VRE have been found in the faecal flora of animals, foods of animal origin or in healthy humans from the general population1 or in hospitalized patients. The only VRE isolated from a hospital patient contained the VanB gene cluster and was acquired abroad. The Swedish example strongly suggests that removal of the selective pressure in animals can remove VRE from the human population in time.”
     
    Just to get back to the sales data issue: you stress that we can’t rely on the sales data to tell a compelling story, and I think we would agree to some extent. We think sales are illustrative but we would certainly benefit from more detailed information about how antibiotics are actually used. We don’t know, for example, how many of those drugs were used on which species and for which purposes. How often are antibiotics used for growth promotion? For disease prevention? For treatment and control? In which species are food producers using antibiotics the most? Where are they medically important? Where are they production tools? Where are they masking overcrowded and unsanitary conditions? We think those data would help the federal government tailor antibiotic policies to preserve those practices that really do protect sick animals. And that’s why we’ve urged the FDA to collect and report these data, both under its existing authority and via new authority under reauthorization of the Animal Drug User Fee Act, which Congress is expected to pass this year.