04/05/2013 04:38 pm ET Updated Jun 05, 2013

Biased Reviews of MRSA Study Could Lead to Bad Policy Decisions

Abraham Maslow famously said "If you only have a hammer, you tend to see every problem as a nail."

Similarly, if you only want to ban antibiotic use in animals, then every study and every event is evidence for your position.

A recent study from Denmark on MRSA is such an example. The study found an unusual strain of matching or nearly matching MRSA in two humans and in some of the animals on small backyard farms in Denmark. This study confirmed what has been known for years - that bacteria, which can sometimes cause infections, can and do move from animals to humans as well as from humans to animals, a process known as zoonosis.

In a matter of hours, the study was being touted as definitive proof that the "overuse" of antibiotics in livestock is endangering human health.

Uh, who said anything about the use of antibiotics?

One infected patient was a woman receiving steroid injections who developed an infection at the injection site which proved to be MRSA. She lived on a farm with two cows, two horses and a dog.
The second infected woman had suffered a severe wound to the forearm with a chainsaw and developed an infection. She lived on a farm with 10 sheep.

Staph bacteria, including MRSA, are likely to be found on skin. That's where researchers would look for them and doctors would closely monitor injection sites and wounds because of the likelihood of bacterial infections.

The MRSA that infected these patients was susceptible to antibiotics other than beta lactam penicillins and both recovered.

There was no mention in the paper that any of the animals had ever been administered antibiotics in any form. We know they did not receive antibiotic growth promoters, as these are banned in Denmark which is one of the strictest countries in the world on antibiotic use in livestock. So antibiotic overuse is to blame?

Ironically, those who rush to judgment on the use of antibiotics in livestock frequently point to Denmark as an example of responsible antibiotic use, and claim that small scale farming would eliminate the antibiotic resistance problem.

This study doesn't even conclusively prove the MRSA found on the humans came from the animals. At least in one of the cases, it's just as likely the bacteria could have spread from humans to animals.
Many studies - including a recently published paper by the Institute of Food Technologists -- along with the food and public health agencies in the United States and Europe all conclude MRSA is not a food safety concern since there is no evidence it can be transmitted through consumption of food or contracted by handling meat.

MRSA is an important public health issue. It emerged decades ago in hospital settings, later in community settings, and most recently in livestock. Suggesting that it is caused by the heavily-regulated use of antibiotics in livestock is misguided and leads to bad public policy decisions.