Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA.
Proc Natl Acad Sci U S A. 2011 Oct 18;108(42):17480-5. doi: 10.1073/pnas.1107857108. Epub 2011 Oct 3.
Conventional wisdom holds that microbes support their growth in vertebrate hosts by exploiting a large variety of nutrients. We show here that use of a specific nutrient (ethanolamine) confers a marked growth advantage on Salmonella enterica serovar Typhimurium (S. Typhimurium) in the lumen of the inflamed intestine. In the anaerobic environment of the gut, ethanolamine supports little or no growth by fermentation. However, S. Typhimurium is able to use this carbon source by inducing the gut to produce a respiratory electron acceptor (tetrathionate), which supports anaerobic growth on ethanolamine. The gut normally converts ambient hydrogen sulfide to thiosulfate, which it then oxidizes further to tetrathionate during inflammation. Evidence is provided that S. Typhimurium's growth advantage in an inflamed gut is because of its ability to respire ethanolamine, which is released from host tissue, but is not utilizable by competing bacteria. By inducing intestinal inflammation, S. Typhimurium sidesteps nutritional competition and gains the ability to use an abundant simple substrate, ethanolamine, which is provided by the host.
传统观点认为，微生物通过利用大量的营养物质来支持其在脊椎动物宿主中的生长。我们在这里表明，在发炎的肠道腔中，特定营养物质（乙醇胺）的利用赋予了沙门氏菌 Typhimurium（S. Typhimurium）明显的生长优势。在肠道的厌氧环境中，乙醇胺通过发酵几乎或根本无法支持生长。然而，S. Typhimurium 通过诱导肠道产生呼吸电子受体（连四硫酸盐）来利用这种碳源，这支持了乙醇胺的厌氧生长。肠道通常将环境中的硫化氢转化为硫代硫酸盐，然后在炎症期间将其进一步氧化为连四硫酸盐。有证据表明，S. Typhimurium 在发炎肠道中的生长优势是因为它能够呼吸乙醇胺，乙醇胺是从宿主组织中释放出来的，但不能被竞争细菌利用。通过诱导肠道炎症，S. Typhimurium 规避了营养竞争，并获得了使用丰富简单底物乙醇胺的能力，乙醇胺是由宿主提供的。
