Antibiotic resistance genes in freshwater trout farms in a watershed in Chile

Irene Bueno, Dominic Travis, Gerardo Gonzalez-Rocha, Julio Alvarez, Celia Lima, Cristián Garcia Benitez, Nicholas B.D. Phelps, Britta Wass, Timothy J. Johnson, Qian Zhang, Satoshi Ishii, Randall S. Singer

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Point sources such as wastewater treatment plants, terrestrial agriculture, and aquaculture may release antibiotic residues, antibiotic resistant bacteria, and antibiotic resistance genes (ARGs) into aquatic ecosystems. However, there is a lack of quantitative studies attributing environmental ARG abundance to specific sources. The goal of this study was to evaluate the role of freshwater trout farms in the release and dissemination of ARGs into the environment. Sediment samples upstream and downstream from five rainbow trout farms were collected over time in southern Chile. A microfluidic quantitative polymerase chain reaction approach was used to quantify an ARG array covering different mechanisms of resistance, and data were analyzed using principal component analysis (PCA) and linear mixed regression models. Surveys were also conducted to obtain information about management practices, including antibiotic use, at the farms. Florfenicol and oxytetracycline were used at these farms, although at different rates. A total of 93 samples were analyzed. In the PCA, , , , , (A), (B), (C), (W), and grouped together. A statistically significant increase in abundance of , , , and several genes was found downstream from the farms compared with upstream sites, and retention ponds had the highest ARG abundance at each site. Antibiotic resistance gene levels returned to baseline at an average distance of 132.7 m downstream from the farms. Although results from this study indicate an influence of trout farms on the presence of ARGs in the immediate environment, the extent of their contribution to ARG dissemination is unknown and deserves further investigation.

Original languageEnglish (US)
Pages (from-to)1462-1471
Number of pages10
JournalJournal of Environmental Quality
Issue number5
StatePublished - Sep 2019

Bibliographical note

Funding Information:
The authors would like to acknowledge Dr. Andrea Moreno Switt and her laboratory staff (Universidad Andres Bello, Chile) for assistance with sample handling. Partial funding was provided by the Institute on the Environment (IonE), the University of Minnesota, the Consortium on Law and Values in Health, Environment & the Life Sciences (University of Minnesota), the Thesis Travel Research Award (University of Minnesota), and the Anderson Fellowship (University of Minnesota).

Publisher Copyright:
© 2019 The Author(s). Re-use requires permission from the publisher.


  • Animals
  • Anti-Bacterial Agents
  • Chile
  • Drug Resistance, Microbial
  • Ecosystem
  • Farms
  • Fresh Water
  • Genes, Bacterial
  • Trout

PubMed: MeSH publication types

  • Journal Article


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