Elevated Microbial Tolerance to Metals and Antibiotics in Metal-Contaminated Inductrial 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, and
3Westinghouse Savannah River Company, Savannah River National
Labortory, Aiken, South Carolina 29808
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.
