Urdaneta Verónica, Casadesús Josep
Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain.
Front Med (Lausanne). 2017 Oct 3;4:163. doi: 10.3389/fmed.2017.00163. eCollection 2017.
Bile salts and bacteria have intricate relationships. The composition of the intestinal pool of bile salts is shaped by bacterial metabolism. In turn, bile salts play a role in intestinal homeostasis by controlling the size and the composition of the intestinal microbiota. As a consequence, alteration of the microbiome-bile salt homeostasis can play a role in hepatic and gastrointestinal pathological conditions. Intestinal bacteria use bile salts as environmental signals and in certain cases as nutrients and electron acceptors. However, bile salts are antibacterial compounds that disrupt bacterial membranes, denature proteins, chelate iron and calcium, cause oxidative damage to DNA, and control the expression of eukaryotic genes involved in host defense and immunity. Bacterial species adapted to the mammalian gut are able to endure the antibacterial activities of bile salts by multiple physiological adjustments that include remodeling of the cell envelope and activation of efflux systems and stress responses. Resistance to bile salts permits that certain bile-resistant pathogens can colonize the hepatobiliary tract, and an outstanding example is the chronic infection of the gall bladder by . A better understanding of the interactions between bacteria and bile salts may inspire novel therapeutic strategies for gastrointestinal and hepatobiliary diseases that involve microbiome alteration, as well as novel schemes against bacterial infections.
胆汁盐与细菌有着复杂的关系。胆汁盐的肠道池组成由细菌代谢塑造。反过来，胆汁盐通过控制肠道微生物群的大小和组成在肠道稳态中发挥作用。因此，微生物群 - 胆汁盐稳态的改变可能在肝脏和胃肠道病理状况中起作用。肠道细菌将胆汁盐用作环境信号，在某些情况下用作营养物质和电子受体。然而，胆汁盐是抗菌化合物，可破坏细菌膜、使蛋白质变性、螯合铁和钙、对DNA造成氧化损伤，并控制参与宿主防御和免疫的真核基因的表达。适应哺乳动物肠道的细菌物种能够通过多种生理调节来耐受胆汁盐的抗菌活性，这些调节包括细胞包膜重塑、外排系统激活和应激反应。对胆汁盐的抗性使得某些耐胆汁病原体能够在肝胆道定植，一个突出的例子是胆囊被慢性感染。更好地理解细菌与胆汁盐之间的相互作用可能会激发针对涉及微生物群改变的胃肠道和肝胆疾病的新型治疗策略，以及针对细菌感染的新方案。
