Dr. H. Morgan Scott, a veterinary epidemiologist in the Department of Veterinary Pathobiology at Texas A&M University, along with colleagues at West Texas A&M University and Kansas State University, recently participated in an important academic debate concerning biological risks associated with feedlot dust in west Texas. Their views were featured in an April 3, 2015 article posted below. The debate stems from a recent peer-reviewed paper published in the journal Environmental Health Perspectives (EHP); subsequent media coverage of the paper has resulted in a few misleading headlines and news articles concerning the spread of “superbugs.” Dr. Scott and colleagues contend that in the EHP paper several inferences were presented as conclusions, when in reality they remain untested hypotheses. Contrary to much of the media representation of this research, the data do not indicate whether there were any viable bacteria present in the samples; therefore, there is no direct evidence of “superbugs.” The likelihood of non-viable bacterial genes transforming into other living bacteria is of very low probability, and thus the biological risk associated with the dust must be considered extremely low. Ongoing public concerns about antimicrobial use and resistance in animal agriculture continue to this day; an important component of addressing those concerns is healthy debate and discussion among scientists.
Scientists dispute study on antibiotic residues in feed yard dust
By John Maday, Editor, Bovine Veterinarian
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 feed yards.
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.
Last 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 re-population and the concentration of antimicrobials found in the feed yard 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.”