肠道菌群与恶性肿瘤的研究进展

人类微生物群是由寄生在人体上皮屏障的细菌和其他微生物组成的，其中大部分位于肠道内，与宿主之间形成共生的关系。机体肠道微生物的组成虽然受到年龄、饮食、生活方式等因素的影响，但在正常生理情况下是相对稳定的。近年来，肠道菌群与恶性肿瘤的关系越来越受到重视。肠道菌群不但能够维持局部稳态，还能调节机体代谢、炎症和免疫等生理过程。有研究表明，微生物群，特别是肠道菌群能够显著调节机体对癌症治疗的反应性以及机体对毒副反应的敏感性。检查肠道菌群中各菌种之间的比例可作为筛查恶性肿瘤的新方法。本文将综述微生物群具有影响肿瘤的发生发展、抗肿瘤治疗疗效以及药物不良反应的证据，以及其中所涉及的微生物种类，从而为恶性肿瘤精准治疗提供证据。     

Antimicrobial activity of selected synbiotics targeted for the elderly against pathogenic Escherichia coli strains

The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.