Good news, bad news, on the use of antibiotics in livestock

First the good news: the FDA is now requiring prescriptions for antibiotics used in livestock. Time will tell if this has any impact on the sheer tonnage of antimicrobials used in agriculture.

As for the bad news, I’m not confident that I can do justice to this publication about “feather meal” as an avenue for antibiotic re-entry into our food supply. Here is an excerpt from the abstract:

...Following poultry slaughter, feathers are converted by rendering into feather meal and sold as fertilizer and animal feed, thereby providing a potential pathway for reentry of drugs into the human food supply. We analyzed feather meal (n = 12 samples) for 59 pharmaceuticals and personal care products (PPCPs) using EPA method 1694 employing liquid chromatography tandem mass spectrometry (LC/MS/MS). All samples tested positive and six classes of antimicrobials were detected, with a range of two to ten antimicrobials per sample. Caffeine and acetaminophen were detected in 10 of 12 samples. A number of PPCPs were determined to be heat labile during laboratory simulation of the rendering process. Growth of wild-type E. coli in MacConkey agar was inhibited by sterilized feather meal (p = 0.01) and by the antimicrobial enrofloxacin (p < 0.0001) at levels found in feather meal. Growth of a drug-resistant E. coli strain was not inhibited by sterilized feather meal or enrofloxacin. This is the first study to detect antimicrobial residues in feather meal.

Two to ten antimicrobials per sample! Concentrations high enough to inhibit growth of wild-type E. coli! I’m going to outsource my outrage to Tara Smith, who has an excellent post on this.

Tragedy of the commons: Antibiotics in Agriculture

@marynmck broke the story right before Christmas that FDA had silently posted that they are backing-off of their long-held (1977) plan to limit overuse of agricultural antibiotics. Instead of formal bans and policy change the FDA now hopes to “focus its efforts for now on the potential for voluntary reform and the promotion of the judicious use of antimicrobials in the interest of public health.”

So here is the current US policy for protecting a critical and diminishing resource for public health:  Please Please Please don't use antibiotics!  Please?  How about if I'm nice? No? Pretty Please. Sugar on top?  Perhaps we should call this the "Don't let the Pigeon Drive the Bus Policy."  I guess it kinda worked in the book. Kinda.

So after burying the bad news on a Thursday before a major holiday weekend, the FDA posted some sort of half-good news right after the new year. You guys excited?  So what was the good news?  They will limit cephalosporins (woo woo) but with so many loopholes and restrictions that it won't matter much. Today, a NYT Editorial in frustration pointed out that FDA "will ban the injection of the antibiotics into chicken eggs and halt the practice of giving large, sustained doses to cattle and pigs. But it still allows widespread use in animals like rabbits and ducks, and veterinarians will still be able to use the drugs in ways not specifically approved by the FDA."

We've written about this issue many times before.  It's amazing that we continue to squander critical antibiotics in animal populations, while at the same time barely funding efforts to develop new antibiotics or new infection prevention strategies. The NYT stated today that "it’s time for the FDA to consider the public’s health as carefully as it considers the interests of intensive agriculture and pharmaceutical companies." Hear Hear.

Sources:

1) Maryn McKenna, Superbug Blog 12/23/2011
2) NYT Editorial "FDA Creeps Forward" 1/11/2012

Antibiotic resistance on the farm



Photo:  Jeff Roberson, Associated Press


Today's LA Times has a well-written article on the relationship between agricultural use of antibiotics and antibiotic resistance. You can read it here. 

2nd ASM-ESCMID Conference on MRSA in Animals

"Am I not destroying my enemies when I make friends of them?"

Just a quick note that ASM has announced the date/location of the 2nd ASM-ESCMID Conference on Methicillin-resistant Staphylococci in Animals. The chair of the conference is Iowa's own Tara Smith.  The conference will be held September 8-11, 2011 in DC.  Abstracts are due June 17th.

Meeting Page: 2nd ASM-ESCMID Conference on MRSA in Animals

Cowboy hats always win? FDA nudges towards limiting antibiotics in animal feed

According to an article in today's NY Times, the FDA has just released a new policy limiting agricultural antibiotic uses to settings protecting animal health, and stating that veterinarians should be involved in the drugs’ uses. Various estimates suggest that between 13% and 70% of total antibiotic use occurs in agricultural settings solely to promote animal growth. These new changes may reduce slightly the amount of penicillins and tetracyclines used in animals. However, it is not clear that limiting "old" antibiotics such as these will have a large impact on MDR-bacteria in humans since it represents marginal use of antibiotics with resistance genes/mechanisms already circulating.

This quote from the article seems accurate: "In the battle between public health and agriculture, the guys with the cowboy hats generally win."

NY Times article (here)

Program Alert: Food, Inc. on PBS Wed 4/21

Last year, Mike recommended the movie Food, Inc. I just received an email from Barb Kowalcyk, a friend and one of the stars of the documentary, announcing that it will be on your local PBS station this Wednesday, April 21. Barb and I worked together for years on the USDA Food Safety Inspection Service's National Advisory Committee on Microbiological Criteria for Foods (NACMCF). She is the co-founder of the non-profit, Center for Foodborne Illness Research & Prevention (CFI). Her story and her son Kevin's story are featured in the movie.

Azoles on the farm

There’s another agricultural antimicrobial controversy brewing. This time it isn’t antibacterial use in animals, but rather the widespread use of azole antifungal agents to protect crops from fungal disease. The Science summary, here, is good, so read it for yourself (subscription required for access to full text). The bottom line: Paul Verweij's group in the Netherlands is building a strong circumstantial case that agricultural azole use is contributing to the emergence of azole-resistant A. fumigatus infections in humans.

Since I have a particular interest in antifungal resistance, I have long been following the reports from the Netherlands of azole resistant Aspergillus fumigatus infections. Our group has been doing global surveillance for azole resistance among Aspergillus for years, and it has remained very uncommon, although last year we found an apparent cluster of azole-resistant A. fumigatus (we’ll publish the details sometime soon, in collaboration with CDC investigators).

Despite my interest in antifungal resistance, I had no idea until recently that there were so many different azoles being used on crops (at least 30 are marketed for agricultural use!). Interestingly, there is little agricultural azole use in the U.S., far more in Europe and elsewhere. As most of you know, invasive aspergillosis is a devastating infection with a very high mortality rate, and the newer azoles are the drugs of choice for both treatment and prevention in high risk patients. Widespread emergence of azole-resistance among Aspergillus would be a very bad thing, indeed.

Want to see a good movie?

I highly recommend Food, Inc., a documentary on the food production industry with Eric Schlosser (author of Fast Food Nation) and Michael Pollan (author of The Omnivore's Dilemma). It's a sad and chilling look at exploitation--of animals, low-paid industry workers, farmers and consumers. Among the many unintended consequences shown in the movie are antibiotic resistance and the emergence of E. coli H7:O157.

It's not just for chickens, cattle and pigs anymore...

The New York Times today has an article about Chile's salmon production industry, which is the second largest in the world. What does this have to do with infections you might ask? Well, it's about the abuse of antibiotics by the salmon industry, just like that which is occurring in other types of food animal production. And it occurs for the same reason as it does in nonaquatic agribusiness--the animals are kept in extremely crowded conditions, which increases the transmission of infectious diseases, and so antibiotics are added to the food (in this case poured directly into the water in which the fish swim) in an attempt to keep them healthy. In this way, antibiotics enter the human food supply and eventually lead to antibiotic-resistant infections in humans. For example, in Europe vancomycin-resistant enterococci (VRE) in humans can be traced to the use of the antibiotic avoparcin in animal feed. Avoparcin is a glycopeptide antibiotic, the same family of antibiotics to which vancomycin belongs. So when the bacteria colonizing the animals who ate the antibiotic-treated food became avoparcin-resistant they were likewise vancomycin-resistant. Back to the salmon--Chile dumped 718,000 pounds of antibiotics in the salmon's water last year. To put that into perspective, by my calculations, that's equivalent to the amount of antibiotics that could treat 23 million adults each for 10 days.

Curbing antibiotic resistance

The editorial page of today's New York Times calls on Congress to pass the Preservation of Antibiotics for Medical Treatment Act. The piece notes that 70% of all antimicrobial use in the US is used in animal production, driving our worsening problems with antibiotic resistance. The legislation would place major restrictions on the routine addition of antibiotics to animal feeds.

Another reason to be a vegetarian

I just finished reading The Face on Your Plate, a book by Jeffrey Masson that explores the impact of eating meat on the environment, the cruelty the animals endure, and the denial that humans continue to exhibit with regard to all of this. He notes that the intense animal production by huge agribusiness is linked to zoonotic diseases, including new strains of influenza. The specific link to H1N1 influenza is outlined in an interesting article in The Guardian last month by Mike Davis. Although H1N1 has received a huge amount of media attention, this aspect of the story has seen little coverage.