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Vendredi, 30 Décembre 2011 17:00

FDA Documents Show Agency Once Strongly Opposed Farm Antibiotic Overuse

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FDA Documents Show Agency Once Strongly Opposed Farm Antibiotic Overuse

The use of antibiotics and sulfonamide drugs, especially in growth promotant and subtherapeutic amounts, favors the selection and development of single and multiple antibiotic-resistant and R-plasmid-bearing bacteria.

Animals that have received either subtherapeutic and/or therapeutic amounts of antibiotic and sulfonamide drugs in feeds may serve as a reservoir of antibiotic resistant pathogens and non-pathogens. These reservoirs of pathogens can produce human infections.

The prevalence of multi-resistant R-plasmid-bearing pathogenic and nonpathogenic bacteria in animals has increased and has been related to the use of antibiotics and sulfonamide drugs.

Organisms resistant to antibacterial agents have been found on meat and meat products.

If you give the text above a close read, you might think it was written by Mark Bittman or Tom Philpott or Tom Laskawy, or me — or any of the small number of journalists who focus on the safety and policy perils of giving scarce antibiotics to confinement-raised farm animals. After all, what it says is what any of us would say: Routine administration of antibiotics to livestock spurs the emergence of drug-resistant bacteria that move through the food chain, threaten human health, and lend their DNA to yet other bacteria, increasing the reservoir of resistance in a dangerous and untracked manner.

As it happens, though, the text above wasn’t written by any of us. It was written by the Food and Drug Administration, the FDA.

Yes, the FDA — the federal agency that, as I wrote last Friday, has just backed off a 34-year attempt to assert regulatory control over “growth promoter” antibiotic use, opting instead for voluntary self-policing by the agricultural and pharmaceutical industries.

The text above comes from the FDA’s original 1977 attempt to withdraw penicillin from animal feeds by revoking the drug’s approval for that use. It’s an excerpt from the Notice of Opportunity for a Hearing (NOOH) that the agency published in the Federal Register on Tuesday, Aug. 30, 1977. That notice and a companion NOOH revoking approval for tetracycline (published in the Federal Register Friday, Oct. 21, 1977) are what the FDA withdrew last Thursday.

What those original documents make clear is that the FDA has never had any uncertainty about the risks posed by subtherapeutic and prophylactic use of antibiotics in large-scale agriculture. It has only lacked the power, funding or will to push back against sustained opposition from industry and from Congress (which you can see in this timeline).

Because they date from 1977, the original notices aren’t accessible through the Federal Register search engine. They were retrieved by the Natural Resources Defense Council, which has been pressing a lawsuit against the FDA for not pursuing the withdrawal of approvals. For easy accessibility, I’ve placed pdfs of them on Scribd: the penicillin NOOH here and the tetracyclines one here.

(That lawsuit, filed in May 2011, may have triggered the FDA’s reneging on the original withdrawal notices, in that it put pressure on the agency to support its 34-year-old intentions. It’s also an example of how people periodically have called on the FDA to follow through on its proposed ban. One purpose of the lawsuit was to force the FDA to pay attention to two “citizens’ petitions” filed in 1999 and 2005 by the groups Public Citizen, Center for Science in the Public Interest, Union of Concerned Scientists and Food Animal Concerns Trust. In a parallel move to last week’s, the FDA ignored those petitions for years, but denied them once the lawsuit was brought.)

The 1977 withdrawal notices make fascinating reading. For one thing, they throw light on the FDA’s history on this issue, which is surprisingly science-based. They say the FDA began examining subtherapeutic use of antibiotics even before the 1969 publication of the Swann Report in the UK, which first raised the alarm about resistant bacteria emerging as a result of agricultural antibiotic use. (Important context: This was occurring in a period when concern about infectious disease risks was at an all-time low. The Swann Report was published two years after the US Surgeon General famously said — or didn’t say — that it was time to “close the book on infectious disease,” and the US had had only one outbreak of MRSA, in a hospital in Boston.)

Some excerpts from the penicillin NOOH:

The Bureau (of Veterinary Medicine)’s primary concern is with that portion of increased antibiotic resistance in the ecological system which may result from the practice of using subtherapeutlc levels of penicillin and other antibiotics in animal feed for prolonged periods. This practice, which sometimes produces increases in growth promotion/feed efficiency, provides an ideal environment for selective pressure to operate. When exposed to an antibiotic, the organisms that are drug resistant survive while the growth of other (drug-sensitive) bacteria Is inhibited. Eventually, the antibiotic-resistant organisms predominate in the bacterial population, and continuous antibiotic pressure perpetuates this abnormal situation…

Evidence demonstrates that the use of subtherapeutic levels of penicillin and other antibiotics in animal feed contributes to the increase in antibiotic-resistant E. coli and in the subsequent transfer of this resistance to Salmonella…

A number of studies have shown that humans in contact with animals receiving medicated feed, including subtherapeutic levels of penicillin, have a higher incidence of drug-resistant organisms in their flora than do control populations of individuals without this direct contact…

During the slaughtering process, contamination of carcasses with intestinal microorganisms cannot be prevented. Meat and meat products are often contaminated with antibiotic-resistant E. coli, and these often reach the human consumer…

The Director must conclude that man is exposed to R-plasmid-bearing intestinal bacteria through contact with contaminated food. Because the drug resistance of these bacteria is increased by feeding the animals subtherapeutic levels of antibiotics, such feeding enhances the likelihood of transmitting R-factor bearing bacteria to man through contact with contaminated food.

If you spend any time looking into this issue of inappropriate antibiotic use in agriculture, you fairly quickly run up against the assertion that the case for agriculture’s responsibility is not proven, and there is no clear evidence of risk. (As was said so often by tobacco companies: “More research needed.”) What these 1977 notices make clear is that, once upon a time, the FDA did not agree with that.

In 1977, the agency was very clear that using antibiotics in agriculture in growth-promoter doses caused the emergence of resistant bacteria that moved off the farm to threaten human health. Which makes it all the more disturbing that, 34 years later, the FDA has determined that championing that well-proven case is a losing battle.

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