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Journal of Toxicology
Volume 2011 (2011), Article ID 608349, 6 pages
Research Article

Toxicity of Methylated Bismuth Compounds Produced by Intestinal Microorganisms to Bacteroides thetaiotaomicron, a Member of the Physiological Intestinal Microbiota

1Department of Microbiology I, University of Duisburg-Essen, 45141 Essen, Germany
2Department of Instrumental Analytical Chemistry, University of Duisburg-Essen, 45141 Essen, Germany
3Department of Environmental Analytical Chemistry, University of Duisburg-Essen, 45141 Essen, Germany

Received 14 June 2011; Revised 24 July 2011; Accepted 26 July 2011

Academic Editor: Elke Dopp

Copyright © 2011 Beatrix Bialek et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Methanoarchaea have an outstanding capability to methylate numerous metal(loid)s therefore producing toxic and highly mobile derivatives. Here, we report that the production of methylated bismuth species by the methanoarchaeum Methanobrevibacter smithii, a common member of the human intestine, impairs the growth of members of the beneficial intestinal microbiota at low concentrations. The bacterium Bacteroides thetaiotaomicron, which is of great importance for the welfare of the host due to its versatile digestive abilities and its protective function for the intestine, is highly sensitive against methylated, but not against inorganic, bismuth species. The level of methylated bismuth species produced by the methanoarchaeum M. smithii in a coculture experiment causes a reduction of the maximum cell density of B. thetaiotaomicron. This observation suggests that the production of methylated organometal(loid) species in the human intestine, caused by the activity of methanoarchaea, may affect the health of the host. The impact of the species to reduce the number of the physiological intestinal microbiota brings an additional focus on the potentially harmful role of methanoarchaea in the intestine of a higher organism.