Dr. Jim Gaines, DVM, says the premise that the meat from food animals fed growth-enhancing antibiotics is causing antibiotic resistance in humans is not supported by existing evidence. Rather, he believes part of the problem is due to the fact that human antibiotic dosages are all based on a 154-lb. person.

In a commentary he authored on The Hill.com, Gaines referred to a 2010 survey by the U.S. Department of Agriculture Food Safety Inspection Service, which found that only 0.1% (one out of each 1000 samples) of 4,771 fresh meat samples contained antibiotics.

“The test samples were from the kidneys by which most antibiotics are concentrated and excreted from the body. There was no data on the concentration of antibiotic in the normal cuts of meat such as steaks and chops, and those tissues do not tend to concentrate antibiotics as do the kidneys,” Gaines wrote.

“If you eat a lot of beef, pork, or lamb kidneys then you have a one in 1000 chance of ingesting a miniscule amount of antibiotic. If you do not eat kidneys on a regular basis then you will ingest a still smaller amount of antibiotic from 0.1% of the common cuts of meat,” he continued.

In addition to being a veterinarian, Dr. Gaines is board-certified in Laboratory Animal Medicine. While serving 20 years in the U.S. Air Force, he participated in medical and dental research. He also has been author and co-author on a number of peer-reviewed scientific publications and authored a book called, "Old Spouse's Tales about Animals.”

“I have been a licensed and practicing veterinarian since 1962 and have treated a variety of animal species from mice to camels in the U.S. and several foreign countries. While serving in the U.S. Air Force, I was involved in medical research for a major part of my tour, including infectious disease research, and I saw essentially no evidence of antibiotic resistant bacteria in all of the species that I have encountered.

“For the powers that are trying to place blame for the growing epidemic of human antibiotic resistance, it is easier to pursue the numerous food animal producers than it is the powerful pharmaceutical industry, the FDA and associated government entities,” he continued.

Antibiotics have a Minimum Inhibitory Concentration (MIC), which has been determined in laboratories as the concentration of a given antibiotic to kill or inhibit a given bacteria growing on nutrient medium in a petri dish. This concentration is then usually tested on the appropriate induced infections in laboratory animals and an MIC for humans is determined.

Gaines explained that the antibiotic dosage for humans is calculated to treat a 154-lb. person.

“A 154-lb. person and a 254-lb. person will receive the same amount of antibiotic for similar infections. The heavier person is receiving 40% less antibiotic per pound body weight than the smaller person, or only 60% of the MIC. A 300-lb. person will get the same daily dose but only half of the MIC. Any person who weighs more than 154 lbs. is being under-medicated with oral antibiotics.”

That means the standard adult dose for most oral antibiotics is per person regardless of weight. Some specific antibiotics are dosed by weight, mainly the intravenous preparations. Antibiotic resistant bacteria for study and testing are created by growing them on a media with low doses of the subject antibiotic and the dose is increased over time and a resistant strain of bacteria is created, said Gaines.

“This is what is happening in humans when heavier people are given inadequate doses of antibiotic,” he said. “Is it any wonder that antibiotic resistance is rampant in humans?”  

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