Scientists dispute study on antibiotic residues in feedyard dust

By John Maday, Editor, Bovine VeterinarianApril 03, 2015 | 5:58 pm EDT
Drovers Cattlenework

In January, we covered a report from Texas Tech University’s Institute of Environmental and Human Health, outlining a study in which researchers detected antibiotic residues, bacteria and genetic material related to antibiotic resistance in particulate matter downwind of Texas feedyards.
The research paper, titled “Antibiotics, Bacteria, and Antibiotic Resistance Genes: Aerial Transport from Cattle Feed Yards via Particulate Matter,” was published in the Journal of Environmental Health Perspectives.
This week, Michael D. Apley, DVM, PhD at Kansas State University, Samuel E. Ives, DVM, PhD at West Texas A&M University and H. Morgan Scott, DVM, PhD at Texas A&M University released a white paper citing concerns over the conclusions listed in the Texas Tech report.
The three research veterinarians focused on issues of bacterial viability, likelihood of bacterial repopulation and the concentration of antimicrobials found in the feedyard particulates.
“In this paper, many inferences are presented as conclusions when in reality they are actually untested hypotheses,” they wrote. Contrary to much of the media representation of this research, the data do not indicate that there are any viable bacteria present in their samples. The likelihood of non-viable bacterial genes transforming into other living bacteria is of very low probability. The antimicrobial concentrations used in this study are not grounded in appropriate air and soil volume concentrations and do not accurately represent the dispersion and dilution of these agents in the environment.” In an interview published this week in the Journal of Environmental Health Perspectives, Dr. Ives says “qPCR techniques only reveal the presence of bacteria, not their viability. That doesn’t translate to transference to the environment and beyond.”
Read the full white paper from Drs. Apley, Ives and Scott.