August 27, 2009
Priya Sharma provided research assistance in the development of this blog.A New York Times editorial from a few weeks back caught my eye because of the link to drug resistance, and that of my colleague, Kim Elliott, who specializes in agriculture trade policy. What concerns could we possibly have in common, Kim and I? You guessed it: antibiotic use in animal-based food production. To quote Kim, “It makes no sense whatsoever!” Kim is right, and anyone who looks at this situation for even a few seconds can easily see that.The Times editors say:
The answer is to develop new antibiotics, you say? Not so fast. There have been very few entrants in that category in recent years and prospects for more are dim. An IDSA report in 2004 counted only 10 new antibiotics approvals since 1998 from the FDA, of which only 2 were novel drugs. In 2002, out of 89 new drugs, no new antibiotics were approved. Antimicrobial resistance seems to be advancing faster than new drugs are developed. The time elapsed between the year an antibiotic was discovered and resistance to it first emerges seems to be getting shorter.* And while resistance emergence does not make a drug useless for all patients, over time resistance spreads and eventually bacteria become sufficiently resistant that the drug is useless (at least for some time – the possibility of reviving drugs by taking them out of circulation temporarily is a good theory but not proven in practice).Effectively, the pipeline for new antibiotics is virtually empty (by new, I mean really new, not using the same mechanism of action as existing antibiotics). The reasons are complex, and some of them are due to continued evolution in pharma industry structure. But the main point is that we don’t have a lot of options left. So why should we use 70% of them on animals? Well, we really shouldn’t. And that is the second point. The large amount of animal-based products in our diets is purely optional. And it is an option that is not enjoyed by much of the rest of the world, although they are quickly taking up our poor diet and showing the same deleterious results that we experience.But even if we must insist on our summer BBQ burgers and chicken nuggets, we don’t need to pump them up with antibiotics. The Europeans forsook that practice years ago and – while they still spend billions to support their agriculture system – they do it without also jeopardizing the efficacy of their drug supply for humans. Agriculture practices are lately being called into question by popular films and in the press. Is it especially smart of the Europeans, therefore, to ban antibiotic use in animals for non-essential purposes? When you consider that it takes upwards of $1 billion to produce a new drug and we’ve seen only two new antibiotics in 10 years, yes, it seems pretty reasonable of them to look for different farming methods, even at higher costs. It may not even be cost effective to use antibiotics in some animal production. (source)Unfortunately, our bad agricultural practices are being spread to other places in the world. The New York Times reports that Chile uses 350 times the amount of antibiotics in its farmed salmon as Norway does. Where would you prefer to get your salmon?And here’s the third (and last) point. It really isn’t a case of Europe preserving antibiotics for Europeans, and the U.S. and Chile wasting antibiotics on animals and fish, because antibiotic resistance travels easily across oceans and continents. We’re all at serious risk of losing the one or two drugs that might keep a scratch from becoming a festering, unhealing wound, or a bout of diarrhea from becoming an endless cycle of drugs that provide only short term relief from dehydration and even death.That’s why the New York Times was bringing Kim and me together, not just at the water cooler, but on the issue of antibiotic use in farming and fishing. The Pew Charitable Trust is promoting legislation called PAMTA or the Preservation of Antibiotics for Medical Treatment Act , which would amend the Federal Food, Drug, and Cosmetic Act. Specifically, it would rescind the approval of seven classes of antibiotics that are important for human medical use, for non therapeutic use in animals. The seven classes of antibiotics are: penicillins, tetracyclines, macrolides, lincosamides, streptogramins, aminoglycosides and sulfonamides. It needs to be supported. It’s either our stomachs (and animal-based products are not so good there either) or our lives.______________________________* - Source: Okeke IN and Sosa A (2003) Africa Health, 25 (3), 10-15
The Union of Concerned Scientists estimates that 70 percent of the antibiotics used in this country are fed to farm animals. These animals do not receive these drugs the way humans do — as discrete short-term doses. Agricultural antibiotics are a regular feed supplement intended to increase growth and lessen the chance of infection in crowded, industrial farms.These practices are putting both humans and animals increasingly at risk. In an environment where antibiotics are omnipresent, as they are in industrial agriculture, antibiotic-resistant strains of diseases quickly develop, reducing the effectiveness of common drugs like penicillin and tetracycline.This is not a recent discovery. More than 10 (TEN!) years ago, the venerable Institute of Medicine cautioned against prevailing trends in agriculture:
Of the approximately 50 million pounds of antibiotics produced in the United States annually, about half is used in animals for therapeutic purposes, disease prophylaxis, and growth promotion. Each year, an estimated 147 pounds of antibiotic are used per acre of farmed salmon and 40,000 to 50,000 pounds of antibiotic are sprayed on fruit trees for control of bacterial infections. (link)What gets my attention is the 50 million pounds figure. If the New York Times is right and the animal proportion of antibiotic use has increased to 70% from about half in 1998, it’s even more than that now. At the rate of most pathogenic mutation, that volume of drugs creates a heck of a lot of selective pressure! Back then, the IOM estimated that between 40-80% of the antibiotics used in livestock production is unnecessary, and 20-50% of physician prescriptions for community-acquired infections were unnecessary.Why does it matter that the majority of antibiotics in the US are consumed by animals, and not by humans to cure human illnesses? First, and fundamentally, there is a limit to the volume of antibiotics that we can pour into animals and ourselves and still expect them to work. We are very very close to that limit right now.Campylobacter is a poultry bacterium that can cause diarrheal disease in humans. Severe cases are treated with quinolone antibiotics like Ciprofloxacin. This group of antibiotics has been used for human medicine since the 1960s, but it wasn’t until the 1990s, when quinolone antibiotics were approved for use in poultry production, that antibiotic resistant Campylobacter emerged (source). While this example certainly doesn’t prove that animal use caused Ciprofloxacin resistance in human disease, there is a strong association between the amount of a specific drug used and resistance to it. The graph below shows resistance in European countries to one class of antibiotics, and a strong association between use and resistance by country.
The answer is to develop new antibiotics, you say? Not so fast. There have been very few entrants in that category in recent years and prospects for more are dim. An IDSA report in 2004 counted only 10 new antibiotics approvals since 1998 from the FDA, of which only 2 were novel drugs. In 2002, out of 89 new drugs, no new antibiotics were approved. Antimicrobial resistance seems to be advancing faster than new drugs are developed. The time elapsed between the year an antibiotic was discovered and resistance to it first emerges seems to be getting shorter.* And while resistance emergence does not make a drug useless for all patients, over time resistance spreads and eventually bacteria become sufficiently resistant that the drug is useless (at least for some time – the possibility of reviving drugs by taking them out of circulation temporarily is a good theory but not proven in practice).Effectively, the pipeline for new antibiotics is virtually empty (by new, I mean really new, not using the same mechanism of action as existing antibiotics). The reasons are complex, and some of them are due to continued evolution in pharma industry structure. But the main point is that we don’t have a lot of options left. So why should we use 70% of them on animals? Well, we really shouldn’t. And that is the second point. The large amount of animal-based products in our diets is purely optional. And it is an option that is not enjoyed by much of the rest of the world, although they are quickly taking up our poor diet and showing the same deleterious results that we experience.But even if we must insist on our summer BBQ burgers and chicken nuggets, we don’t need to pump them up with antibiotics. The Europeans forsook that practice years ago and – while they still spend billions to support their agriculture system – they do it without also jeopardizing the efficacy of their drug supply for humans. Agriculture practices are lately being called into question by popular films and in the press. Is it especially smart of the Europeans, therefore, to ban antibiotic use in animals for non-essential purposes? When you consider that it takes upwards of $1 billion to produce a new drug and we’ve seen only two new antibiotics in 10 years, yes, it seems pretty reasonable of them to look for different farming methods, even at higher costs. It may not even be cost effective to use antibiotics in some animal production. (source)Unfortunately, our bad agricultural practices are being spread to other places in the world. The New York Times reports that Chile uses 350 times the amount of antibiotics in its farmed salmon as Norway does. Where would you prefer to get your salmon?And here’s the third (and last) point. It really isn’t a case of Europe preserving antibiotics for Europeans, and the U.S. and Chile wasting antibiotics on animals and fish, because antibiotic resistance travels easily across oceans and continents. We’re all at serious risk of losing the one or two drugs that might keep a scratch from becoming a festering, unhealing wound, or a bout of diarrhea from becoming an endless cycle of drugs that provide only short term relief from dehydration and even death.That’s why the New York Times was bringing Kim and me together, not just at the water cooler, but on the issue of antibiotic use in farming and fishing. The Pew Charitable Trust is promoting legislation called PAMTA or the Preservation of Antibiotics for Medical Treatment Act , which would amend the Federal Food, Drug, and Cosmetic Act. Specifically, it would rescind the approval of seven classes of antibiotics that are important for human medical use, for non therapeutic use in animals. The seven classes of antibiotics are: penicillins, tetracyclines, macrolides, lincosamides, streptogramins, aminoglycosides and sulfonamides. It needs to be supported. It’s either our stomachs (and animal-based products are not so good there either) or our lives.______________________________* - Source: Okeke IN and Sosa A (2003) Africa Health, 25 (3), 10-15Disclaimer
CGD blog posts reflect the views of the authors, drawing on prior research and experience in their areas of expertise. CGD is a nonpartisan, independent organization and does not take institutional positions.