Collaborative study finds antibiotics in watersheds

A multi-campus collaboration among University of Nebraska system faculty, led by the UNMC College of Allied Health Professions (CAHP), has found antibiotics used in human treatment in two Nebraska agricultural water systems, near Fremont and Lincoln watersheds.

The finding of these antibiotics is deeply concerning, said Wayne Mathews, associate professor and director of research, CAHP physician assistant education.

“It likely could have an impact on our increasing resistance to antibiotics,” Mathews said.

“As clinicians, we hear frequent warnings not to overprescribe antibiotics, and I totally agree with that,” Mathews said. “But, for example, more than 30 percent of common UTI (urinary tract) infections show resistance to antibiotic treatment.” That’s likely more than overprescribing, according to recent research, Mathews said.

And the same study shows that high rates of antibiotic resistance are found in agricultural areas.

So, the NU team did a two-year intensive analysis of the Elkhorn River and Shell Creek watersheds.

In addition to Mathews, the team included:

  • UNMC microbiologist Linsey Donner, assistant professor, CAHP medical laboratory science;

  • University of Nebraska-Lincoln civil and environmental engineer Xu Li, PhD;
  • UNL civil and environmental engineer Shannon Bartelt-Hunt, PhD;
  • UNL analytical chemist Dan Snow, PhD;
  • UNL postdoctoral research associate Jodi Sangster, PhD

“It’s a broad team of experts representing a number of pertinent fields and a great example of what we can achieve working together through System Science grants,” Mathews said.

The findings are significant. The U.S. Food and Drug Administration (FDA) has set up safeguards to keep human antibiotics out of agriculture and thus out of our bodies without a prescription.

But the University of Nebraska team findings show these safeguards aren’t working. Bacteria with an antibiotic-resistant gene is “going directly into drinking water and agricultural water,” Mathews said.

A 2017 FDA regulation requires that any antibiotics in agricultural feed must be prescribed by a veterinarian (and thus not be one used for human care) and should be related to treating or preventing a specific disease.

How does the FDA keep track? “The FDA’s method of measuring was to look at regional antibiotic purchases divided by the biomass,” or number of livestock in the region, Mathews said.

What we found,” Mathews said, “is that method does not guarantee that there are not high levels of antibiotics of human significance in the water,” as mandated by the FDA.

The team presented its findings at the National Institute of Antimicrobial Resistance Research and Education’s (NIAMRRE) annual conference and has been accepted at IDWeek, a prestigious infectious disease conferences, to be published in its Infectious Disease Abstracts.