Center for Infectious Diseases, The University of Texas School of Public Health, Baylor College of Medicine, Kelsey Research Foundation, Houston, TX, USA.
Aliment Pharmacol Ther. 2016 Jan;43 Suppl 1:3-10. doi: 10.1111/apt.13434.
Disruption of the gut microbiota through use of systemic antimicrobials or activation of the mucosal inflammatory response by pathogens can cause dysregulation of the intestinal mucosa.
To explore the mechanisms of action of rifaximin that may underlie its clinical benefits in travellers' diarrhoea (TD).
A literature search was performed using the terms 'rifaximin' and 'L/105' in combination with the terms 'in vitro activity', 'diarrhea', 'microbiota' and 'gut flora'.
Rifaximin has been traditionally identified as a nonsystemic, broad-spectrum, bactericidal antibiotic. Evidence shows that the activity of rifaximin against enteropathogens in this setting is likely enhanced by its increased solubility in the presence of bile acids in the small intestine. Results of clinical studies show that although rifaximin is efficacious in TD, a clinical cure often occurs without apparent bacterial eradication and with minimal effect on the gut microbiota, suggesting an effect of rifaximin other than direct antibiotic activity.
Although definitive studies on the effect of rifaximin on the gut microbiota in large cohorts of healthy volunteers or patients have not been published, pre-clinical studies provide some insight. These studies have shown that rifaximin may have effects on both the pathogen and host, including direct effects on pathogenic bacteria (such as reducing the expression of bacterial virulence factors) and indirect effects on the host (such as inhibiting bacterial attachment and internalisation at the intestinal mucosa and reducing mucosal inflammation).
通过使用全身性抗生素或病原体激活黏膜炎症反应，肠道微生物群可能会失调。
探索利福昔明在旅行者腹泻（TD）中发挥临床疗效的作用机制。
使用“rifaximin”和“L/105”与“体外活性”、“腹泻”、“微生物群”和“肠道菌群”等术语相结合，进行文献检索。
利福昔明传统上被认为是一种非全身性、广谱、杀菌抗生素。有证据表明，在小肠胆汁酸存在的情况下，利福昔明的溶解度增加，其针对肠道病原体的活性可能增强。临床研究结果表明，尽管利福昔明对 TD 有效，但临床治愈通常发生而无明显细菌清除，对肠道微生物群的影响最小，提示利福昔明的作用除了直接的抗生素活性之外还有其他作用。
尽管尚未发表关于利福昔明对健康志愿者或患者肠道微生物群影响的大型队列研究，但临床前研究提供了一些见解。这些研究表明，利福昔明可能对病原体和宿主都有影响，包括对致病菌的直接影响（如降低细菌毒力因子的表达）和对宿主的间接影响（如抑制细菌在肠黏膜的附着和内化，减少黏膜炎症）。
