Fewer antibiotics in your McNuggets is a good thing …

March 11, 2015
Sampling

NIU graduate students David Mills and Linn Kleppe work with NIU researcher Kendall Thu to take water samples from a DeKalb County creek. They found levels of antibiotics and antibiotic-resistant bacteria at levels higher than most similar studies.

To understand the significance of last week’s announcement from McDonald’s – the fast food giant is phasing out the sale of chickens raised using feed laced with the same antibiotics that also can treat humans – look no further than the creeks and rivers of DeKalb County.

After three years of sampling, Melissa Lenczewski and other researchers from NIU found antibiotics in waterways near the university appear at levels higher than in most similar studies around the nation. Furthermore, in response to those drugs, the waterways are also home to a number of antibiotic-resistant bacteria.

Lenczewski, a hydrogeologist, is director of NIU’s Institute for the Study of the Environment, Sustainability, and Energy.

The drugs were washed into the waters by runoff from the swine feed lots across DeKalb County, where hogs outnumber humans 4-to-1. Per instructions from the companies that pay local farmers to operate those facilities, those pigs are fed a diet laced with non-therapeutic levels of antibiotics.

It is standard practice in the meat industry. According to Consumer’s Report magazine, 80-percent of all antibiotics sold in America are used in animal feed. Why? It is a matter of simple economics: Animals fed low levels of antibiotics develop fewer infections; healthier animals grow larger; and larger animals yield greater profits. However, most of the antibiotics that go into those animals eventually come out, and despite modern waste management practices, some of them end up in nearby waterways.

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An NIU researcher samples water in a DeKalb County creek.

In and of itself, the presence of the drugs in the water is not dangerous.

A person would have to drink thousands of liters of the water just to get the equivalent of a single dosage prescribed by a doctor, Lenzewski says. However, nobody really knows what the influence of low levels of multiple drugs will have an ecosystem in the long term. They do know, however, that their presence in the environment encourages bacteria to evolve drug-resistant strains.

In DeKalb County, Lenczewski says, NIU researchers found that 1 percent to 2 percent of all bacteria collected were resistant to the common antibiotics sulfamethazine and ampicillin. None of those bacteria is currently considered dangerous to humans. However, because bacteria are constantly mutating, there is concern that that they could evolve someday into something dangerous that current drugs cannot treat.

Overuse (and misuse) of prescription antibiotics in humans already has contributed to the rise of many so-called “super bugs.” According to the Center for Disease Control, antibiotic-resistant infections, such as methicillin-resistant staphylococcus aureus (MRSA), sicken at least 2 million Americans each year and kill 23,000.

For that reason, anything that can be done to thwart the development of bacteria resistant to antibiotics is a good thing, Lenczewski says. So, when McDonald’s, the nation’s largest buyer of chicken, joined the likes of Chick-fil-A and Chipotle Mexican Grill in demanding chicken raised without human antibiotics, it was a positive thing. However, to be truly effective, such bans must be more inclusive.

“Chickens aren’t the big problem. If they go after beef, that would be a really big step, because the larger animals require more antibiotics and create more waste,” she says.

In fact, pressure from consumers might be moving the industry in that direction. Just days after the news of the new McDonald’s policy, retail giant Costco announced that it is working to eliminate human antibiotics from all meats sold there.

In the meantime, Lenczewski is working at the forefront of research into the issue of antibiotics in waterways. In particular, she is pioneering the use of a simple test strip used in the dairy industry (milk must be certified antibiotic-free) to test for the presence of the drugs in water. The test takes only nine minutes and costs $5, versus the use of a mass spectrometer, which takes several hours and costs between $300 and $500 per sample.

Joe King, NIU Media and Public Relations