When the issue of large-scale manure spreading came up here in Ohio in the 1990s, the thought of antibiotic resistance being transferred to native bacteria crossed my mind. Antibiotics are blended into animal feed to help cut down on animal health problems in confined conditions. Some of the antibiotics are excreted in animal waste.

When we brought up this subject during hearings conducted by the Ohio Department of Agriculture for siting and construction of large animal feeding facilities (LAFF)  -- also known as CAFO --  we got that look from the state personnel: “Are you from the moon, or what?”

It so happens that there have been some studies looking at the problem in manure, and some thin studies of the topic in water (more on that at our website page on large-scale agriculture Concentrated Animal Feeding Facilities...Resources for Environmental Responsibility). However, a University of Illinois study published in 2007 demonstrates the spread of antibiotic resistance 250 meters down stream in ground water. Reference links:

University of Illinois news item on the study
Abstract of study paper in Applied and Environmental Microbiology

The resistance gene (the DNA) spreads faster than the bacteria and is detected in higher amounts in the ground water than in the manure. Weird? It must mean that the genes are being taken up by bacteria in the ground water. They are sampling at wells, of course. I do not have direct knowledge of the sampling protocols or wells. However, one explanation for the increase in gene content is that bacteria growth in biofilms in the wells is amplifying the DNA mass. Another reason to clean wells!

There is movement to curtail the use of antibiotics (particularly those that have parallel human uses) in animal feeding. Also, proper conditioning of the manure prior to spreading reduces gene content.

And then we can start on not siting the things on karst land, or allowing manure spreading on karst land, and requiring the monitoring of ground water around spreading farms and not spreading in our wellhead protection areas.

If hundreds of millions of people are going to eat their fill in meat and eggs, we need big farm operations and they need to extract manure to operate. The manure has benefits – it’s about the greenest form of soil amendment for nutrition. It is not that we need to cut out the use of manure, but that we halt the big bacterial evolution experiment.