ARS | Publication request: Stored swine manure and swine faeces as reservoirs of antibiotic resistance genes

Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 2, 2013
Publication Date: March 18, 2013
Citation: Whitehead, T.R., Cotta, M.A. 2013. Stored swine manure and swine faeces as reservoirs of antibiotic resistance genes. Letters in Applied Microbiology. 56:264-267.

Interpretive Summary: Antimicrobial compounds have been commonly used as feed additives for domestic animals to reduce infection and promote growth. Recent reports have suggested such feeding practices may result in increased microbial resistance to antibiotics, which can have an impact on human health. While many investigations have centered on antibiotic resistance in E. coli and other aerobic bacteria, less attention has been directed towards investigating antibiotic resistance in the normal anaerobic microbes found in the feces and stored manure of domestic animals. As a first step in assessing whether antibiotic resistance is prevalent in these microbes we identified a number of antibiotic resistance genes that are present in both swine feces and stored manure, as well as in individual bacteria isolated from these ecosystems. These results indicate that the swine gastrointestinal tract and stored swine manure may serve as reservoirs of antibiotic resistance genes.

Technical Abstract: Inclusion of low levels of antibiotics in the feed of domestic food animals promotes improved growth, animal performance and overall health benefits. However, this practice has come under scrutiny due to concerns over such feeding on bacterial antibiotic resistance and potential impact on human health. There is a paucity of data on the types and levels of antibiotic resistance genes that may be present in agricultural practices. Using PCR detection of antibiotic resistance genes, this study demonstrates that both stored swine manure and swine feces harbor a variety of antibiotic resistance genes, and bacterial members of these communities contain genes that may move between microorganisms. Thus both ecosystems may serve as reservoirs of antibiotic resistance genes.