Posted 25 July 2011, by Nevil C. Speer, PhD, MBA Western Kentucky University, Dairy Herd Network, dairyherd.com
There’s a lot of misinformation out there about food and food production. Usually we can look the other way, simply shaking it off as a matter of personal preference or fashionable trend that will eventually wane with time. But there’s one issue where that approach is unacceptable: the use of antibiotics in livestock. After all, antibiotic resistance is a matter of public health and thus touches us all. And the issue has been front-and-center in recent months.
The first round came through a public interest group coalition filing suit against the FDA. The coaltion asserts FDA has violated federal law by failing to actively withdraw approval of non-therapeutic penicillin and tetracycline usage in animal feed. Moreover, that failure has occurred despite claims FDA previously concluded such usage facilitates development of antibiotic-resistant bacterial strains. The suit predicated on the claim of, “…growing evidence that the spread of bacteria immune to antibiotics has clear links to the overuse of antibiotics in the food industry.” Dovetailing that effort came via proposed legislation (Preservation of Antibiotics for Medical Treatment) in both the House and Senate. The legislation is aimed at reducing antibiotic use in animal agriculture and predicated on a similar foundation to the lawsuit mentioned above. Dianne Feinstein (D-CA), upon PAMTA’s reintroduction, explains the legislation is necessary to tackle, “The rampant overuse of antibiotics in agriculture that creates drug-resistant bacteria, an increasing threat to human beings….The effectiveness of antibiotics for humans is jeopardized when they are used to fatten healthy pigs or speed the growth of chickens.”
So the logic goes like this: antibiotics fed to livestock at sub-therapeutic levels facilitate establishment of resistant strains of bacteria and absolute containment at the local farm environment proves elusive. That scenario inevitably put citizens at risk because such strains prove unresponsive to treatment if they are able to cause illness. Therefore, the argument is that such use must be curtailed and future approval of new antibiotics in livestock should be preempted. And without any further knowledge, that all makes sense. Something should be done – the rhetoric supports litigation and legislation.
However, this is no drive-by issue. It possesses serious public health implications and demands science-based analysis. To that point, quantified research assessment of potential farm-to-patient resistance transfer represents a “very low risk of human treatment failure” (Hurd et al., Journal of Food Protection, 2004). Simply put, there is no scientifically documented link establishing antibiotic use in livestock and increased resistance in humans.
The counter argument to that fact often revolves the Denmark experience where non-therapeutic antibiotic use has been banned in animal agriculture; ensuing total antibiotic use declined in the livestock sector. But Denmark proponents overlook several important facts. First, therapeutic use actually increased following the ban. Second, there’s been no documentation that antibiotic resistance in the human population has declined since the ban.
The real issue here is public health. The solution is only as good as the weakest link. Resistant bacteria don’t care about ideology or politics. Singling out animal agriculture is a false solution and leaves the risk equation wide open. It doesn’t really address the broader issue of resistance. That demands a comprehensive approach and mandates the medical community being an active part of the solution.
Antibiotic prescription practices must be addressed. Frivolous treatment has become increasingly widespread. Numerous studies reveal patients expect antibiotics regardless of appropriateness of such a prescription. Doctors, often time-crunched and motivated to maintain their respective patient base, often acquiesce to patient pressure. Public health concerns about potential resistance go unaddressed amidst the individual doctor-patient relationship.
Moreover, none of this addresses misuse of antibiotics once the prescription is in hand. Per that note, lest we forget, resistance is not a new phenomenon – Maryn McKenna (Superbug, c. 2010) illustrates:
Penicillin [released to the public in 1944] was a wonder drug, the first glimpse of the antibiotic miracle that would quell the ancient scourge of infectious disease, and its inventors were heroes. A portrait of [Sir Alexander] Fleming appeared on the cover of Time in May 1944 over the caption: “His penicillin will save more lives than war can spend.”…Fleming himself predicted what would happen next. In his speech accepting the Nobel Prize in December 1945, he said:
“There is the danger that the ignorant man may easily under-dose himself and by exposing his microbes to non-lethal quantities of the drug, make them resistant. Here is a hypothetical illustration. Mr. X has a sore throat. He buys some penicillin and gives himself, not enough to kill the streptococci but enough to educate them to resist penicillin. He then injects his wife. Mrs. X gets pneumonia and is treated with penicillin. As the streptococci are no resistant to penicillin the treatment fails. Mrs. X dies.”
Fleming was sadly right, though amidst the joy over penicillin’s impact, the research that would prove his prediction received little publicity. In December, 1940, before the drug had ever been tested in a human, [biochemist Ernst] Chain and his Oxford University colleague Edward Abraham said in a letter to the journal Nature that the common gut bacteria E. coli seemed to be evolving a defense against the new drug and was producing an enzyme that kept penicillin from working. Two years later, Charles Rammelkamp and Thelma Maxon of Boston University demonstrated experimentally that staph bacteria could also develop protection against the effects of penicillin.
Resistance is an unfortunate, and inevitable, drawback of use. But it was a concern at the outset – long before antibiotic use was ever implemented in livestock production.
Does any of this imply animal agriculture is off the hook or should have free license to operate? Absolutely not – that’s neither socially-responsible nor founded on scientific principles. Judicious use of antibiotics is imperative! Moreover, there is a real need to bolster enforcement of already-existing laws – most notably, prosecution of repeat violators.
But at the end of the day, sole focus on sub-therapeutic antibiotic use in livestock doesn’t really address resistance. It simply makes food production an expedient scapegoat while creating a false sense of security. That’s the most dangerous proposition of all.