Antibiotic Resistance Genes in Freshwater Biofilms May Reflect Influences from High-Intensity Agriculture

• Published in: Microbial ecology Vol. 72; no. 4; pp. 763 - 772
• Main Authors: Winkworth-Lawrence, Cynthia, Lange, Katharina
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01.11.2016; Springer US; Springer Nature B.V
• Subjects: Agricultural land; Agriculture - methods; Aminoglycosides; Animals; Animals, Domestic - microbiology; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotic resistance genes; Antibiotics; Antiporters - genetics; Bacteria - drug effects; Bacteria - genetics; Benthos; biofilm; Biofilms; Biofilms - growth & development; Biomedical and Life Sciences; Contaminants; Contamination; Databases, Factual; Drug resistance; Drug Resistance, Bacterial - genetics; Ecology; farming systems; Fresh water; Fresh Water - microbiology; Freshwater; Genes; Genes, Bacterial - genetics; Genetic screening; Geoecology/Natural Processes; Glycopeptides; Humans; Inland water environment; Interspersed Repetitive Sequences - genetics; Land pollution; Land use; Life Sciences; macrolides; Methyltransferases - genetics; Microbial Ecology; Microbial Sensitivity Tests; Microbiology; MICROBIOLOGY OF AQUATIC SYSTEMS; Nature Conservation; New Zealand; nitrogen; Phosphates; Public health; recreation areas; Resistance to antibiotics; Rocks; Tetracycline Resistance - genetics; Tetracyclines; Water Quality/Water Pollution; Waterways; winter; PSE, New Zealand; New Zealand; Total nitrogen; Antibiotic resistance genes; Freshwater; Land use
• ISSN: 0095-3628; 1432-184X; 1432-184X
• DOI: 10.1007/s00248-016-0740-x

Antibiotic resistance is a major public health concern with growing evidence of environmental gene reservoirs, especially in freshwater. However, the presence of antibiotic resistance genes in freshwater, in addition to the wide spectrum of land use contaminants like nitrogen and phosphate, that waterways are subjected to is inconclusive. Using molecular analyses, freshwater benthic rock biofilms were screened for genes conferring resistance to antibiotics used in both humans and farmed animals (aacA-aphD to aminoglycosides; mecA to ß-lactams; ermA and ermB to macrolides; tetA, tetB, tetK, and tetM to tetracyclines; vanA and vanB to glycopeptides). We detected widespread low levels of antibiotic resistance genes from 20 waterways across southern New Zealand throughout the year (1.3 % overall detection rate; 480 samples from three rocks per site, 20 sites, eight occasions; July 2010–May 2011). Three of the ten genes, ermB, tetK, and tetM, were detected in 62 of the 4800 individual screens; representatives confirmed using Sanger sequencing. No distinction could be made between human and agricultural land use contamination sources based on gene presence distribution alone. However, land use pressures are suggested by moderate correlations between antibiotic resistance genes and high-intensity farming in winter. The detection of antibiotic resistance genes at several sites not subject to known agricultural pressures suggests human sources of resistance, like waterway contamination resulting from unsatisfactory toilet facilities at recreational sites.