Maryn McKenna

Journalist and Author

Drug-Resistant Bacteria: To Humans From Farms via Food

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You have to love a scientific commentary that starts this in-your-face:

“Show us the science that use of antibiotics in animal production is causing this antibiotic resistance,” Dave Warner of the National Pork Council told the Washington Post back in June 2010, responding to a Food and Drug Administration (FDA) guidance document advising against the sub-therapeutic use of antibiotics in livestock.

Well, here’s some.

To be clear: That’s the paper’s language, not mine. The gut-punch challenge comes from an editorial that is only on the web so far but is scheduled for publication in the journal Clinical Microbiology and Infection. It accompanies a research article that makes an important claim:

Chickens, chicken meat and humans in the Netherlands are carrying identical, highly drug-resistant E. coli — resistance that is apparently moving from poultry raised with antibiotics, to humans, via food. [Read more…]

Ag antibiotic use: Risky — but also sloppy and wasteful

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So, antibiotics. Given to farm animals. (Yeah, that again.) How does that work, anyway? Pills? Injections? Daily massage with specially compounded creams?

Not quite. Farm animals overwhelmingly get antibiotics in their feed. (You knew that.) And a new paper in the journal Environmental Health Perspectives explains what a bad idea that is: Animals that are given “free choice medicated feeds” (FCMF, in the jargon) can overdose or under-dose themselves, leading not only to the creation of antibiotic-resistant bacteria but to the accumulation of antibiotic residues in their flesh that can persist past slaughter.

There are two issues hidden in this. The first is the practice of giving tiny doses of antibiotics as “growth promoters,”  a use that dates back to the late 1940s. Despite a fair amount of study, there are still competing explanations for how this actually works, but the results are clear: Give animals micro-doses of antibiotics, and they put on weight faster, meaning they get to market size and can be sold — and replaced by another batch to whom the same thing happens — more quickly than if the drugs were not being used. The second is using treatment-sized doses in feed to take care of any illnesses among animals, as well as to protect animals who might pick up those illnesses in the close quarters of confinement agriculture.

If you view animal raising as an industrial-style process, the equivalent of making widgets on a production line, then medicated feed appears to make economic sense, because it offers a substantial return for little forward investment of money or labor. But as this paper picks apart, medicated feeds are not the bargain they seem. [Read more…]

News break: Slaughter will reintroduce PAMTA (and cites data from this blog)

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Rep. Louise Slaughter (D-NY), Congress’s only microbiologist, said late today that she plans shortly to reintroduce PAMTA, the Preservation of Antibiotics for Medical Treatment Act, a timely move given the collapsing antibiotic market (see this morning’s post) and continuing reports of resistance moving off farms (as in this post).

PAMTA would direct the FDA to re-examine its approvals of veterinary antibiotics that are close analogs of ones used in humans, because they can stimulate the development of resistant organisms. When those organisms move off the farm, as research shows they do, they then cause illnesses that cannot be treated by the functionally identical human drugs.

The Union of Concerned Scientists said in 2008 about an earlier version of the bill:

The FDA is aware of the problem of antibiotic resistance due to overuse in animal agriculture, but the agency’s process for reviewing and withdrawing drugs from the market is far too slow and cumbersome. A recent effort to withdraw an antibiotic from use by poultry producers due to concerns about human antibiotic resistance lasted for more than five years, costing millions of taxpayer dollars. And while the judicial proceedings dragged on, disease-causing bacteria continued to outwit antibiotics.

While some producers and retailers of meat products have announced policies that take steps to curb antibiotic use, private-sector initiatives to reduce antibiotic use in animal agriculture are relatively rare, limited in scope, and difficult to verify. Federal action is needed to achieve comprehensive reductions and create a level playing field for all producers and retailers.

Passage of PAMTA is critical to keep antibiotics working for human health. In addition to averting the harmful effects of antibiotic overuse on human health, curtailing animal use of antibiotics will encourage producers to raise animals in better living conditions that are less conducive to disease.

Parenthetically, it is flattering to see Slaughter reference new data on the amount of antibiotics used in animals in the United States — almost 29 million pounds — and the percentage of the total market antibiotic market that represents: 80 percent. Those pieces of news were broken over the Congressional break by myself, here at SUPERBUG, and by Ralph Loglisci at the blog of the Center for a Livable Future.

Flickr/net_efekt/CC

Giant pig farms: Antibiotic resistance is not the only problem

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When I talk about farming, I usually focus on antibiotic over-use and the way that it stimulates the emergence of drug-resistant organisms. That’s part of what my recent book is about, and to me, it’s the critical piece in the entire discussion of industrial-scale agriculture. If we didn’t use antibiotics in such vast quantities, confined animal-feeding operations, CAFOS, couldn’t exist: Animals couldn’t survive in those conditions without them.

But so many other negatives come from CAFOs — not just antibiotic resistance, but air and water contamination, and chronic human diseases caused by effluent and pollution. I’m grateful to be reminded of that via a webinar hosted this afternoon by the Institute for Agriculture and Trade Policy, which threw a sharp light on the impact of industrial-scale hog farming in North Carolina.

The webinar took a close look at new research by University of North Carolina associate professor Steven Wing. His paper, just published on the website of the journal Epidemiology, details the acute physical symptoms experienced by North Carolina residents who live in areas near very large hog farms: eye irritation, wheezing, chest tightness, shortness of breath, sore throat and nausea.

Emerging from the farms, Wing said, are “dust, and particles from dried feces, as well as spraying of waste that aerosolizes that material. There are several important gases such as ammonia and hydrogen sulfide… as well as bioaerosols, which include endotoxin from dead bacteria. Some of these materials… are allergenic and can cause respiratory problems.”

(See Wing’s image above of manure spraying, and dead-pig disposal, outside a North Carolina hog farm.)

To get that data, Wing and colleagues at UNC and Mount Sinai School of Medicine collaborated with residents of eastern North Carolina, especially the Concerned Citizens of Tillery, in a project dubbed Community Health Effects of Industrial Hog Operations (CHIEHO). They recruited 101 adults in 16 communities who agreed to sit outside for 10 minutes twice a day, every day for two weeks, and to log their symptoms and also measure their lung function with a flow meter. Separately, the team measured ambient air pollution with continuous monitors that were parked in each community.

Overall, between September 2003 and 2005, they received 2,900 responses about people’s symptoms in the previous 12 hours, 2,600 about symptoms that were provoked by those episodes of sitting outdoors, and 1,900 error-free measurements of lung function. And — no surprise for anyone who knows what these farms look like and smell like — the symptoms tracked with the air pollution measurements.

Wing asked: “Is it fair to tell anyone they can’t go outside their own home because it is too polluted to be there?”

Here’s why conditions outside those eastern North Carolina houses are so bad. Within two miles of each of the communities that contributed to the research, there was an average of 42,000 hogs. Within North Carolina as a whole, there are more than 10 million hogs on more than 2,400 farms. The distribution looks like this:

The spots where the dots cluster most densely are Duplin and Sampson counties. Duplin contains 45 hogs for every resident; Sampson, 32. Something else those areas have in common, mentioned during the webinar by Naeema Muhammad, from Concerned Citizens of Tillery:

Most of those operations are in eastern North Carolina, and eastern North Carolina is where you have your predominantly African-American communities, …other communities of color and also your highest rates of poverty. Looking at that map, we are able to use the phrase “environmental racism.”

Wing and colleagues add in their paper:

…in low-income communities of color… there is more potential for exposure to outdoor air pollutants due to older homes that are not air tight and have no air conditioning. Many residents also lack the financial resources to travel and choose activities that could help them avoid high pollution. Exposure to air pollution from hog operations is an environmental injustice in rural areas hosting facilities that supply pork to populations spared the burdens of its production.

IATP said today they will subsequently post a recording of the webinar along with its slides; I’ll update when it goes live.

Cite: Schinasi, L et al. Air Pollution, Lung Function, and Physical Symptoms in Communities Near Concentrated Swine Feeding Operations. Epidemiology 2011;22: 208–215. DOI: 10.1097/EDE.0b013e3182093c8b

Images: Dead pigs and manure spraying at a North Carolina farm/Institute for Agriculture and Trade Policy + S. Wing, UNC; map of North Carolina hogs farms/IATP + S. Wing, UNC (adapted from Wing et al. 2001)



Opposing industrial-scale pig farming — in Europe

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Well, wow. National legislators stand up to oppose the use of tax revenues to subsidize large-scale confinement pig farms out of concern for food safety and antibiotic resistance, declaring that they are “going to war in defense of pigs.”

In Europe, though.

At the European Parliament today, three national representatives — Janusz Wojciechowski of Poland, José Bové of France and Dan Jørgensen of Denmark — declared their opposition to industrial-scale swine agriculture, positioning themselves for a fight over the European Union’s Common Agriculture Policy, which is up for revision this summer.

Jørgensen represents the country that has done the most to place controls on agricultural antibiotic use; Bové is a farmer and political organizer who famously destroyed a McDonald’s by driving a tractor through it; and Wojciechowski is the son of pig farmers who wrote on his blog today:

Chcemy poruszyć sumienia posłów i doprowadzic do likwidacji tego typu “fabryk miesa” w Unii Europejskiej, no czywiscie takze w Polsce, gdzie takich fabryk jest juz ponad sto.
Chcemy doprorowadzic do tego, aby wielkie fermy nie były wspierane środkami europejskimi, aby wstrzymać lokalizacje nowych obiektów, po czym stopniowo likwidować te, które już istnieją.
Chcemy, żeby na miejsce fabryk miesa powróciła normalna hodowla świń.
We want to move the conscience of members and lead to the liquidation of this type of “meat factories” in the European Union, also in Poland, where such plants are already over a hundred.
We want to ensure that large farms are not supported by the European funds to stop the locations of new facilities, then gradually eliminate those that already exist.
We want “meat factories” returned to normal breeding of pigs. (via GoogleTranslate)

As I’ve written before (long archive here and here),the MRSA strain ST398 arose on Dutch pig farms in 2004, among pigs that had been given prophylactic doses of antibiotics, especially tetracycline. It has since spread through the EU, Canada and the United States, affecting not only farm workers and veterinarians, but also hospital patients with no connection to agriculture.

(Self-promotion alert: This may be a good time to tell you that my book SUPERBUG: The Fatal Menace of MRSA, which tells the full story of the emergence and spread of ST398, has just been released in paperback.)

In advance, this morning the trade paper Farming UK wrote this about the planned European Parliament announcements:

(Members of the European Parliament) will hear evidence that European taxpayers’ money is being used by the European Bank for Reconstruction and Development, together with Common Agriculture Policy payments, to subsidise industrial pig farming even though there is increasing concern over the impact on human health. With a vote this summer over reforms to the Common Agricultural Policy, MEPs will come together to take a stance against the crisis in agriculture with critically low prices for pork, poor labelling, and widespread disregard for animal welfare laws.

MEPs and NGOs will condemn the overuse of antibiotics in factory farms which has led to the emergence of antibiotic-resistant bacteria such as MRSA and ESBL E. coli. A recent report by the Dutch Food Standards Agency estimated that one third to one half of all antibiotic resistance in human diseases in the Netherlands derives from farm antibiotic use. American scientists recently found that flies and cockroaches from intensive pig farms carry bacteria resistant to the same antibiotics routinely used in pig farming, and warned that the insects were likely to be able to spread the disease from the farms to local people.

The event was co-organized by Tracy Worcester, who is both a British aristocrat and director of a documentary, Pig Business, that has not yet been shown in the US. Here’s its trailer:

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In both medicine and agriculture, Europe has been ahead of the US in addressing concerns about antibiotic resistance. This morning’s announcements are yet more evidence of just how far ahead they are.

Flickr/VickyTGAW/CC

Farm antibiotics, human illness and what connects them. (It has legs.)

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When it comes to the impact of farm antibiotics on human health, there’s a data gap.

That the use of antibiotics on conventional/confinement farms provokes the emergence of drug-resistant bacteria really isn’t in dispute; it’s been proven, over and over again, for about 30 years now. (Here’s a long bibliography from the Pew Charitable Trusts that lists the major pieces of research.) And there’s good research as well that those bacteria move off farms via animals, farm workers, groundwater and air currents. (Another long bibliography here, from the Center for a Livable Future.)

But proving the links between resistant farm bacteria and human illness is trickier. Among the reasons: When an individual person who is sick with a foodborne illness goes to the doctor, that doctor does only enough testing to figure out how to treat them. The kind of subtyping you would need to do on a foodborne organism to prove its farm-drug link isn’t useful to a primary-care physician, and the equipment isn’t accessible either; it’s found in academic medical centers and state public health labs. But the public health system isn’t filling the data gap either. The CDC’s main foodborne outbreak-tracking program, FoodNet, monitors the prevalence of 10 illness-causing organisms, but doesn’t test for antibiotic resistance. And the joint federal program that does monitor resistance, NARMS (for National Antimicrobial Resistance Monitoring System, shared by the CDC here, USDA here and FDA here) uses randomized anonymized samples from humans, animals and retail meat, so it can’t illuminate whether resistant bacteria are causing outbreaks.

So are resistant bacteria from farms causing outbreaks of human illness? The Center for Science in the Public Interest says yes. In a white paper published this week, the group documents 35 outbreaks between 1973 and 2009 for which epidemiologic and microbiological links are clear. Quoting from the report:

  • Reporting of outbreaks due to antibiotic-resistant bacteria has increased in each decade since the 1970s, with 40% (14 out of 35) occurring in the last decade … Outbreaks were most common in dairy products (34%) and ground beef (26%). Two outbreaks each were linked to poultry, pork, produce, and seafood, and one outbreak each was linked to eggs and multi-ingredient foods. The food vehicle was unknown in four of the outbreaks.
  • A total of 19,897 people were sickened from these 35 outbreaks, resulting in 3,061 hospitalizations and 26 deaths.
  • For the 31 outbreaks for which antibiotic-resistance patterns were determined, the responsible bacteria displayed resistance to a total of 14 different antibiotics … Of those antibiotics, seven are classified by the World Health Organization (WHO) as ‘critically important’ to human medicine and eight as ‘highly important’ to human medicine. Bacteria showed resistance to tetracycline in 30 outbreaks. Resistances to streptomycin and ampicillin, both classified as critically important antibiotics, were the next most common. Bacteria associated with 19 outbreaks were resistant to at least five antibiotics. Fifteen of those occurred between 1990 and 2009.

There’s still a data gap, of course: Exactly how are the organisms getting from the animals or their manure into the guts of humans? Via meat, or milk, is the logical assumption. But an article also published this week suggested the organisms might have help — from cockroaches and flies.

Researchers from Kansas State University and North Carolina State University scooped up house flies and German (common) cockroaches on conventional confinement farms in both states, and also scooped up poop from the pigs being grown on the farms. They tested all three for the presence of resistant forms of the common gut bacteria Enterococci. Almost all — 89 percent of the pig-manure samples, 94 percent of the cockroach guts and 98 percent of the flies’ guts — contained Enterococci. Of the Enterococci, at least 90  percent of those found in each species were resistant to tetracycline; from 50 percent to 70 percent were resistant to erythromycin; and from 10 percent to 40 percent were resistant to ciprofloxacin and streptomycin — NB, all drugs used in essentially identical forms in humans as well as livestock. PFGE analysis of the Enterococci from the pigs and the insects showed they were carrying the same bacterial clones.

The researchers write:

Organic wastes in and around animal production
facilities including swine farms provide excellent habitats for house flies and German cockroaches. Several features of house flies and cockroaches, including their dependence on live microbial communities, active dispersal ability and human-mediated transport, attraction to places where food is prepared and stored, developmental sites, and mode of feeding/digestion make these insects an important “delivery vehicle” for transport of bacteria including antibiotic resistant enterococci from reservoirs (animal manure), where they pose minimal hazard to people, to places where they pose substantial risk (food)…

High frequency of resistance to tetracycline, erythromycin, streptomycin, kanamycin, and
ciprofloxacin in our study likely reflects use of tetracyclines, macrolides, aminoglycosides and
fluoroquinolones as feed additives for swine in the USA… The source of antibiotic resistant
enterococci in house flies and cockroaches in this study was the swine manure due to very high
prevalence of antibiotic resistant enterococci in all three sources.

Cite: Ahmad, A et al. Insects in confined swine operations carry a large antibiotic resistant and potentially virulent enterococcal community. BMC Microbiology, 26 January 2011, 11:23doi:10.1186/1471-2180-11-23

Food bin Flickr/j_bongio/CC; Fly face Flickr/e_monk/CC

Farm worker infections with MRSA — the first numbers

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Since the first identification in 2004 of MRSA ST398, also known as “pig MRSA” or livestock-associated MRSA (archives of posts here and here), that drug-resistant organism has been found being carried asymptomatically by farm workers and veterinarians, and causing illness in health care workers, hospital patients, and people with no known ties to agriculture. One of the persistent data gaps, though, has been whether farm workers themselves have been made sick by it.

It’s a difficult question to answer for a nested set of reasons: First, in most of the states, MRSA (methicillin-resistant Staphylococcus aureus, or drug-resistant staph) is not a reportable disease; that is, a doctor who diagnoses it in a patient is under no obligation to tell any public health authority about that patient’s case. And second, the testing required to distinguish livestock-associated MRSA from community-acquired or hospital-acquired is not something that primary-care medical personnel have access to; you have to go to a state laboratory or an academic medical center to do the appropriate molecular typing. Those tests are expensive to perform, and their results primarily are useful to public health, not to individual medical practitioners. So finding out where that nascent epidemic is going has been unusually challenging.

Comes now a team from the University of Iowa — the same team that first identified ST398 in pigs and pig-farm personnel in the United States — to start to fill the gap. [Read more…]

Update: Farm Animals Get 80 Percent of Antibiotics Sold in U.S.

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Two weeks ago, I broke the news of a new FDA report that estimated for the first time the amount of antibiotics sold in the United States every year for use in agriculture: 28.8 million pounds.

That long-awaited report didn’t answer a crucial question: What volume of antibiotics are sold in the United States each year for human use. It’s a crucial question because, in answer to concerns about antibiotic resistance arising on farms, the answer has always been that human medicine is equally culpable because it uses similar volumes of antibiotics.

The only research that has attempted to answer that question is contained in a decade-old report by the Union of Concerned Scientists that put the proportion of antibiotics going to animals at 70 percent of the U.S. total.

That UCS report and estimate are a decade old not because no one has cared about the topic, but because accurate updated figures have been so hard to get. So we owe a special holiday thank-you to the researchers at the Center for a Livable Future, who decided the release of the FDA report justified another attempt to get the numbers straight. They succeeded.

The proportion of antibiotics sold in the United States each year that go to animals turns out to be not 70 percent, but rather 80 percent. Here’s CLF’s Ralph Loglisci, who got the confirmatory numbers from the FDA:

In accordance with a 2008 amendment to the Animal Drug User Fee Act, for the first time the FDA released last week an annual amount of antimicrobial drugs sold and distributed for use in food animals. The grand total for 2009 is 13.1 million kilograms or 28.8 million pounds. I … contacted the FDA for an estimate of the volume of antibiotics sold for human use in 2009. This is what a spokesperson told me:

“Our Office of Surveillance and Epidemiology just finished an analysis based on IMS Health data. Sales data in kilograms sold for selected antibacterial drugs were obtained as a surrogate of human antibacterial drug use in the U.S. market. Approximately 3.3 million kilograms of antibacterial drugs were sold in year 2009. OSE states that all data in this analysis have been cleared for public use by IMS Health, IMS National Sales Perspectives™.”

3.3 million kilograms is a little over 7 million pounds. As far as I can determine, this is the first time the FDA has made data on estimates of human usage public.

At its blog, CLF lays out the math for each major drug class as sold for animal use and human use, with a long discussion of the significance of the different drug classes. Here’s the CLF table summing up the math, but please go over to CLF’s blog for its discussion.

Most important to note: Most of the drugs used in animal agriculture and in human medicine are functionally identical. That’s one reason why the overuse of antibiotics in animals is such a concern: When organisms become resistant on the farm to drugs used on livestock, they are becoming resistant to the exact same drugs used in humans. (One major drug category used in animals, ionophores, do not have a direct human analog. But use of them on farms is still a concern, because resistance factors can move freely between species of bacteria. That’s a discussion for another day.)

Loglisci’s conclusion is also worth underlining:

The next battle, which industry has already begun, is defining what non-therapeutic use will constitute. Producers are already claiming that the use of antibiotics for growth promotion has decreased, maintaining current low-dose usage is aimed at disease prevention. Regardless, all low-dose usage of antibiotics can lead to a significant increase in antibiotic resistance.

Image: Flickr/Epsos

"Pig MRSA": New human infections in France

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It’s one of the touchiest topics under the broad category of antibiotic resistance: Whether the drug-resistant organisms that emerge on farms as a result of antibiotic use stay on farms, or pose a risk to humans who have no connection to agriculture.

That drug resistance emerges under any selective pressure is basic biology: Resistance is an inevitable process. That they emerge on farms when antibiotics are used broadly — that is, in growth-promoting or prophylactic ways, not to treat disease in individual animals — really isn’t in dispute any more. It’s now a question of economics and politics, not science. (See this bibliography, stretching back to 1969; and the news I broke yesterday of FDA’s estimate of US farms using almost 29 million pounds of antibiotics last year.)

So the argument over farm antibiotic use now tends to focus on whether the resistant organisms that emerge on farms are only an issue within a farm’s confines, or rather pose a broader human health threat — and that’s where the continuing story of the “third epidemic” of MRSA becomes so important. Recapping, this is a strain known as MRSA ST398 that emerged in pigs and passed to pig farmers in the Netherlands in 2004, subsequently spread across the European Union, and crossed to Canada and then to the United States. (Key posts on ST398: here, here, here and this archive at my old site. Yes, it will be moved soon, promise.)

Most of the identifications of MRSA ST398 in humans, including those first identifications above, were colonizations, the term for symptomless carriage of staph in the nostrils and on the skin; in other words, it wasn’t making people sick. News of actual illnesses has been rare — especially illnesses among people who have no contact with farming, such as the post-surgical infections found in Canada earlier this year.

But they’re getting a little less rare, as demonstrated by a letter just posted ahead-of-print to the journal Clinical Infectious Diseases. It recounts the finding, via annual surveys of bloodstream infections, of four cases of ST398 in four different hospitals in France. One may have been due to animal exposure. Three were hospital-acquired.

Examination of patient histories revealed exposure to animals in 1 case, a fatal idiopathic community-acquired bloodstream infection in an 84-year-old man who lived on a farm at which 1 pig was being raised. The remaining cases were hospital-acquired and included 1 case of catheter-associated infection observed in a 58-year-old man with advanced multiple myeloma, 1 case following elective digestive tract surgery in a 69-year-old woman, and 1 case following cardiac surgery in a 68-year-old man.

There’s an especially interesting thing about these cases. In Europe and the US, ST398 has particular characteristics: It is resistant to tetracycline (the drug most commonly given to pigs) and does not manufacture the toxin Panton-Valentine leukocidin or PVL, which is suspected to be a cause of community-strain MRSA’s uncommon virulence. (See this story, from the book SUPERBUG, of how PVL-positive pneumonia almost killed a toddler.) The strain in the French cases, though, does manufacture PVL, and shares some virulence characteristics with the dominant community strain, USA300. It is less like the European strain of livestock-associated MRSA and more like a livestock-associated strain that appears to be emerging in China, ST9 (more on that here).

The argument against the significance of these cases is likely to be that they are, again, just one data-point, and may be just rare and random. That is worth considering. But it is also worth considering that they continue to be found.

And, also, that the community epidemic of MRSA was first flagged in a discovery of 25 cases in children in Chicago back in 1998, a finding that was also dismissed at the time as rare and random — and that grew into an epidemic of millions of cases a year.

(H/t to constant reader Pat Gardiner for flagging this paper for me.)

Cite: van der Mee-Marquet N et al. Emergence of Unusual Bloodstream Infections Associated with Pig-Borne–Like Staphylococcus aureus ST398 in France. Clin Infect Dis. (2011) 52 (1): 152-153. doi: 10.1093/cid/ciq053

Image via Flickr user johnmuk under CC

News break: FDA estimates US livestock get 29 million pounds of antibiotics per year

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This afternoon, the Food and Drug Administration posted without fanfare a report that many people have been waiting a long time for: Its first-ever estimate of the amount of antibiotics sold for use in food animals in the United States.

And the number is: almost 29 million pounds in 2009.

That’s a lot.

Is it more or less than was expected? It’s almost impossible to say. Estimates of the amount of antibiotics given to food animals in the United States are ferociously contested and plagued by squishy definitions and category creep. In 2000, the Animal Health Institute, which represents veterinary drug manufacturers, put total use at 17.8 million pounds. In 2001, the Union of Concerned Scientists, which campaigns (among other issues) to dial back use of agricultural antibiotics, estimated that 24.6 million pounds per year are used only for “non-therapeutic purposes” — that is, to make animals grow to market weight faster and to prevent them catching diseases in the close quarters of confinement agriculture.

The reason why antibiotic use on farms is a concern, of course, is because such use stimulates the emergence of drug-resistant organisms that move off the farm in animals, in groundwater, in dust, on the wind and in the systems and on the clothes of those who work there, and makes new resistance factors available to be swapped among bacteria. (For much more about that, see these three posts and this long archive at my former blog.)

The FDA’s estimate comes as the agency has been moving to curb agricultural antibiotic use after years of non-action. Today’s report, which is very short — basically a table and a bunch of footnotes — is the direct result of a 2008 amendment to the Animal Drug User Fee Act of 2003, which required manufacturers to report yearly on sales of agricultural antimicrobials. (Here’s an FDA Q&A on the report background.)

More important, though, today’s report dovetails with the FDA’s new effort to curb antibiotic use in agriculture, which Commissioner Dr. Margaret Hamburg said in October would involve “very serious scrutiny.” (Video here.) The main instrument of that effort is a “draft guidance” that the FDA opened for public comment over the summer, “The Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals” (pdf here). The point of that guidance is to ask agriculture to voluntarily withdraw from use the ag drugs that are functionally identical to drugs that are important in human medicine — because if bacteria become resistant to those drugs when they are used in animals, that newly derived resistance will also affect humans, making common diseases difficult or impossible to treat.

In addition to the volume figure, the real value of today’s brief report may be simply to make clear just what antibiotics are used in agriculture. Take a look at the report table at right, which lists the animal drugs used by amount sold within drug classes. (Note that the amounts are given in kilograms.) It lists:

Aminoglycosides: Human versions include streptomycin and amikacin.

Cephalosporins:  Human versions include Keflex and Rocephin.

Lincosamides: Human versions include clindamycin.

Macrolides: Human versions include erythromycin.

Sulfas: Human versions include half of the very common drug combos Bactrim and Septra.

Penicillins and tetracyclines: Yup, just what they sound like.

“NIR”: That’s FDA shorthand for “not independently reported” because they have few manufacturers or make up a small portion of the market. Among them are fluoroquinolones. Human versions: Cipro and Levaquin.

There’s much more to be said about the issue of antibiotic use in agriculture, especially because the lone piece of legislation addressing it, the Preservation of Antibiotics for Medical Treatment Act, is currently in lame-duck limbo. This report is an important piece of data for the ongoing debate.

Update: I asked some experts in the field to comment on the release of this data. Dr. David Wallinga, director of the Food and Health program at the Institute for Agriculture and Trade Policy in Minneapolis (also William T. Grant Foundation Distinguished Fellow in Food Systems and Public Health at the University of Minnesota School of Public Health) replied:

Clearly, antibiotic use in animal agriculture is huge, and as the FDA and CDC and WHO all agree, much of it is unnecessary. Data collection is important. But, because resistant bugs quickly adapt, we can’t afford to wait for data to take action to reduce antibiotic use wherever possible. That includes routine uses of antibiotics for cattle developing liver abscesses because they’re force-fed grain rather than grass, as well as antibiotics used to make animals get fatter faster.

Update 2: A day after the release of this report, Rep. Louise Slaughter (D-NY), author of PAMTA and a public-health microbiologist, commented on the data — and also said she’ll be reintroducing the legislation again in the next Congress in January.

This report illustrates the overuse of antibiotics in food animal production and makes a strong case for some common-sense limits on antibiotic use. We are putting millions of pounds of antibiotics into the food supply unnecessarily every year. This cannot continue and it’s my hope that these new data from the FDA will encourage even more members of Congress to join me next year when I reintroduce this legislation.  Moreover, the FDA must move fast to issue strong regulations on antibiotic usage in agriculture.

Update 3: Tom Philpott, senior food and agriculture writer at Grist — and a farmer, so he knows the territory — covered the FDA report and this post in a very kind and typically forthright post of his own.

Update 4: Helena Botttemiller, ace food-policy reporter for Food Safety News, covers this as well, noting how little mainstream media interest there has been. Any opinions why?

Cite: 2009 Summary Report on Antimicrobials Sold or Distributed for Use in Food-Producing Animals, FDA, Dec. 9, 2010

Image via Flickr user net_efekt under CC

News break: FDA head promises "very serious scrutiny" of farm antibiotics

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Since July, the Food and Drug Administration has been moving — quietly and cautiously, but moving — to raise the stakes in its long and so-far unsuccessful battle to rein in overuse of antibiotics in agriculture. For those new to the topic, this is the use of antibiotics not in treatment-sized doses, to cure disease in farm animals, but in smaller doses to prevent disease or simply to make the animals gain weight faster so they can raised more efficiently and sold off more quickly than they would have otherwise.

There are decades of research by now, demonstrating that this contributes to the development of antibiotic-resistant organisms on farms that then move off harms and threaten human health. It’s not really a scientific question any longer; it’s a question of economics and politics.

(For a long discussion of what the FDA is proposing — and how much force it will, or won’t, have — see this post — at SUPERBUG’s earlier location, because we haven’t yet moved over all the archives.)

Yesterday, FDA Commissioner Dr. Margaret Hamburg gave a speech at the National Press Club at which she raised this issue and made some intriguing remarks. The overall point of the speech (see this AP article) was to promise increased investment and modernization — but she raised both the problem of antibiotic resistance generally and, in answer to a question, the problem of antibiotic use in farming.

First, here’s what she said generally about resistance (my transcription from CSPAN’s video above, starting at about 7:00):

There is increasing alarm about the problem of antibiotic resistance, and we worry with good cause. Today, antibiotic resistance mechanisms have been reported for virtually all known antibacterial drugs currently available for clinical use, which affects everything from global infectious diseases to ear infections in school children to staph infections in locker rooms. People actually talk today about a potential return to the, quote, pre-antibiotic era, unquote, where we no longer have effective tools to treat serious infectious disease. Clearly we must encourage more judicious use of these important drugs through improved infection control,  rational prescribing and better patient compliance.

But even if we improve these practices, resistant bacteria will continue to develop no matter what. We need new and better drugs and we need them now. Yet the research and development pipeline is distressingly low. The number of newly approved antibiotics, not just new formulations of previously existing drugs, has fallen steadily since the 1980s, and the range of new antibiotics in distribution is limited in terms of the types of classes of new antibiotics available and the diseases they can treat.

And here’s what she said about farm use, in response to a question (starting at about 31:00):

There historically has been a very considerable use of antibiotics as part of animal husbandry and also agriculture. I think that for many years individuals and organizations in public health and medicine have raised those very concerns, about what is the impact of the use of antibiotics in animal populations on human health and the availability of effective antibiotics to treat disease. We are in the midst of very serious scrutiny of these issues and we have made recommendations in support of judicious use of antibiotics. Nobody wants to deny antibiotics to animals that need medical treatment. But the use in certain preventive contexts, where it is not clearly medically indicated, is of growing concern,. And it is an area that, working with our partners in government, both the CDC and the USDA and others, that we are taking a very serious look at. (Emphasis mine.)