SREL Reprint #2834

Elevated Microbial Tolerance to Metals and Antibiotics in Metal-Contaminated Industrial Environments

Ramunas Stepanauskas1, Travis Glenn1,2, Charles H. Jagoe1, R. Cary Tuckfield3, Angela H. Lindell1, and J V. McArthur1

1Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, South Carolina 29802
2Department of Biological Sciense, University of South Carolina, Columbia, South Carolina 29208
3Westinghouse Savannah River Company, Savannah River National Labortory, Aiken, South Carolina 29808

Abstract: To test the hypothesis that industrial metal contaminants select for microorganisms tolerant to unrelated agents, such as antibiotics, we analyzed metal and antibiotic tolerance patterns in microbial communities in the intake and discharge of ash settling basins (ASBs) of three coal-fired power plants. High-throughput flow-cytometric analyses using cell viability probes were employed to determine tolerances of entire bacterioplankton communities avoiding bias toward culturable versus nonculturable bacteria. We found that bacterioplankton collected in ASB discharges were significantly more tolerant to metal and antibiotic exposures than bacterioplankton collected in ASB intakes. Optical properties of microorganisms collected in ASB discharges indicated no defensive physiological adaptations such as formation of resting stages or excessive production of exopolymers. Thus, it is likely that the elevated frequency of metal and antibiotic tolerances in bacterioplankton in ASB discharges were caused by shifts representative in microbial community composition, resulting from the selectlve pressure imposed by elevated metal concentrations or organic toxicants present in ASBs.

SREL Reprint #2834

Stepanauskas, R., T. C. Glenn, C. H. Jagoe, R. C. Tuckfield, A. H. Lindell, and J. McArthur. 2005. Elevated microbial tolerance to metals and antibiotics in metal-contaminated industrial environments. Environmental Science & Technology 39:3671-3678.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).