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Science 339 (6120): 708-711

Copyright © 2013 by the American Association for the Advancement of Science

Host-Derived Nitrate Boosts Growth of E. coli in the Inflamed Gut

Sebastian E. Winter,1 Maria G. Winter,1 Mariana N. Xavier,1 Parameth Thiennimitr,1,2 Victor Poon,1 A. Marijke Keestra,1 Richard C. Laughlin,3 Gabriel Gomez,3 Jing Wu,3 Sara D. Lawhon,3 Ina E. Popova,4 Sanjai J. Parikh,4 L. Garry Adams,3 Renée M. Tsolis,1 Valley J. Stewart,5 Andreas J. Bäumler1,*

Abstract: Changes in the microbial community structure are observed in individuals with intestinal inflammatory disorders. These changes are often characterized by a depletion of obligate anaerobic bacteria, whereas the relative abundance of facultative anaerobic Enterobacteriaceae increases. The mechanisms by which the host response shapes the microbial community structure, however, remain unknown. We show that nitrate generated as a by-product of the inflammatory response conferred a growth advantage to the commensal bacterium Escherichia coli in the large intestine of mice. Mice deficient in inducible nitric oxide synthase did not support the growth of E. coli by nitrate respiration, suggesting that the nitrate generated during inflammation was host-derived. Thus, the inflammatory host response selectively enhances the growth of commensal Enterobacteriaceae by generating electron acceptors for anaerobic respiration.

1 Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, One Shields Avenue, Davis, CA, USA.
2 Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
3 Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA.
4 Department of Land, Air and Water Resources, University of California, Davis, One Shields Avenue, Davis, CA, USA.
5 Department of Microbiology, College of Biological Sciences, University of California, Davis, One Shields Avenue, Davis, CA, USA.

* To whom correspondence should be addressed. E-mail: ajbaumler{at}ucdavis.edu

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