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标题：Chemical sensing in mammalian host–bacterial commensal associations
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作者：David T. Hughes ; Darya A. Terekhova ; Linda Liou 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：21
页码：9831-9836
DOI：10.1073/pnas.1002551107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The mammalian gastrointestinal (GI) tract is colonized by a complex consortium of bacterial species. Bacteria engage in chemical signaling to coordinate population-wide behavior. However, it is unclear if chemical sensing plays a role in establishing mammalian host-bacterial commensal relationships. Enterohemorrhagic Escherichia coli (EHEC) is a deadly human pathogen but is a member of the GI flora in cattle, its main reservoir. EHEC harbors SdiA, a regulator that senses acyl-homoserine lactones (AHLs) produced by other bacteria. Here, we show that SdiA is necessary for EHEC colonization of cattle and that AHLs are prominent within the bovine rumen but absent in other areas of the GI tract. We also assessed the rumen metagenome of heifers, and we show that it is dominated by Clostridia and/or Bacilli but also harbors Bacteroidetes. Of note, some members of the Bacteroidetes phyla have been previously reported to produce AHLs. SdiA-AHL chemical signaling aids EHEC in gauging these GI environments, and promotes adaptation to a commensal lifestyle. We show that chemical sensing in the mammalian GI tract determines the niche specificity for colonization by a commensal bacterium of its natural animal reservoir. Chemical sensing may be a general mechanism used by commensal bacteria to sense and adapt to their mammalian hosts. Additionally, because EHEC is largely prevalent in cattle herds, interference with SdiA-mediated cattle colonization is an exciting alternative to diminish contamination of meat products and cross-contamination of produce crops because of cattle shedding of this human pathogen.
关键词：bovine ; enterohemorrhagic Escherichia coli ; metagenomics ; rumen