Is antibiotic use in livestock killing humans?

ABThis morning, I awoke to several “news stories,” suggesting that low level and regular antibiotic use in livestock is contributing to widespread antibiotic resistance.

An example from SFGate (a San Francisco local news and entertainment portal), entitled “Report links antibiotics at farms to human deaths”:

“The Centers for Disease Control on Monday confirmed a link between routine use of antibiotics in livestock and growing bacterial resistance that is killing at least 23,000 people a year.”

Other headlines, mostly from websites promoting vegetarian diets and opposing “factory farming,” state emphatically that the CDC has “discovered a link” between the administration of antibiotics and antibiotic resistance:”

“Antibiotics Used to Make Livestock More Profitable May Be Killing Us” – Truth Out

“Farm Antibiotics Linked to Human Deaths: CDC” – NewMaxHealth

I took the time to download and read the actual report (crazy, I know), “Antibiotic Resistance Threats in the US: 2013”. Within the report, there are statements of concern regarding risks of low level antibiotic use on factory farms. The CDC suggests that the practice should be phased out.

However, nowhere in the text does the CDC attribute any of the (estimated) 23,000 yearly deaths from drug resistant infections to livestock farming specifically. The report provides no indication as to what percentage of deaths are due to antibiotic use on farms, nor to any other specific cause.

This is, of course, for good reason. No one really knows.

What I found interesting, was a graphic that illustrates how drug resistant bacteria (and fungi) emerge and infiltrate the human population. In the graphic, there are two possible scenarios:

1) Resistance develops within the human gut, and resistant strains of bacteria spread through institutional environments by way of contact with fecal matter and due to improper cleaning and sterilization procedures.

2) Resistance develops within the animal gut, and drug resistant bacteria enter the human population through improperly cooked meat and through poor management of animal discharge with contaminates vegetable crops which humans eat.

The first scenario, is, of course, an operational problem. Out patient procedures are becoming more common to minimize the possibility of spreading resistant bacteria within institutional environments, but obviously it is impossible to contain every possible pathway at all times.

The second is more interesting, but again, this is also an operational problem. The first pathway, contact with uncooked meat, is a fairly easy problem to solve on an individual level. Cook your burgers or buy your horse sashimi only from places you can trust. Of course, there is no failsafe here.

The problem of discharge management is also an operational one. Farms have to maintain standards to insure that animal waste does not contact, say spinach farms as happened back in 2009.

I cannot say whether antibiotic use is good or bad for raising livestock (having no expertise in the field), though I will take many of colleagues words at face value and assume that it is not necessary and that the potential costs outweigh the benefits. The jury seems to be out on the issue, however.

However, it would appear from the CDC report, that the greater potential for harm comes from operational issues, which should be resolved in any case. Though resistant bacteria are a threat to human health (and potentially detrimental to the long term economic health of the food industry), there are many other threats that follow the exact same transmission pathways. The e. coli outbreak in California spinach in 2009 is a great example.

Though I understand that those who oppose meat eating or factory farming wish to use what I would call a distortion of the fact and the CDC report to further a particular political position, it would seem that those interested in protecting human health would be far better off calling for more stringent standards within the livestock industry.

So, to answer the question in the title: “Is antibiotic use in livestock killing humans?, ” I have the following responses:

1. It is not clear from the CDC report that any of the 23,000 deaths have anything to do with livestock.

2. Assuming that any of the deaths have anything to do with livestock, the problem would appear to have more to do with how food is cooked (dumbass factor) and the poor management of animal waste (both of which also come with other threats to human health).

Now, before anyone accuses me of trying to minimize the problem, it is true that antibiotic resistance is a serious, serious problem. Antibiotics are over prescribed in the United States to humans, and new antibiotics are not being developed (mostly). We’ve run out of options to fight existing bacteria and as long as doctors are willing to hand antibiotics out like candy, the problem will only become more severe.

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NOTE: Now, this blog post is not a defense of the livestock industry, nor a call for greater use of antibiotics. In general, however, I take issue with misuse and distortions of data for political aims on any part of the political spectrum. Call it a weakness of mine.

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About Pete Larson

Assistant Professor of Epidemiology at the Nagasaki University Institute for Tropical Medicine

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