Department of Veterinary Biosciences, Microbiology, University of Helsinki, Helsinki, Finland.
Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.
Gut. 2014 Nov;63(11):1737-45. doi: 10.1136/gutjnl-2013-305994. Epub 2013 Dec 5.
About 10% of patients with IBS report the start of the syndrome after infectious enteritis. The clinical features of postinfectious IBS (PI-IBS) resemble those of diarrhoea-predominant IBS (IBS-D). While altered faecal microbiota has been identified in other IBS subtypes, composition of the microbiota in patients with PI-IBS remains uncharacterised.
To characterise the microbial composition of patients with PI-IBS, and to examine the associations between the faecal microbiota and a patient's clinical features.
Using a phylogenetic microarray and selected qPCR assays, we analysed differences in the faecal microbiota of 57 subjects from five study groups: patients with diagnosed PI-IBS, patients who 6 months after gastroenteritis had either persisting bowel dysfunction or no IBS symptoms, benchmarked against patients with IBS-D and healthy controls. In addition, the associations between the faecal microbiota and health were investigated by correlating the microbial profiles to immunological markers, quality of life indicators and host gene expression in rectal biopsies.
Microbiota analysis revealed a bacterial profile of 27 genus-like groups, providing an Index of Microbial Dysbiosis (IMD), which significantly separated patient groups and controls. Within this profile, several members of Bacteroidetes phylum were increased 12-fold in patients, while healthy controls had 35-fold more uncultured Clostridia. We showed correlations between the IMD and expression of several host gene pathways, including amino acid synthesis, cell junction integrity and inflammatory response, suggesting an impaired epithelial barrier function in IBS.
The faecal microbiota of patients with PI-IBS differs from that of healthy controls and resembles that of patients with IBS-D, suggesting a common pathophysiology. Moreover, our analysis suggests a variety of host-microbe associations that may underlie intestinal symptoms, initiated by gastroenteritis.
约 10%的 IBS 患者报告在感染性肠炎后出现综合征。感染后肠易激综合征（PI-IBS）的临床特征类似于腹泻为主型肠易激综合征（IBS-D）。虽然在其他 IBS 亚型中已经确定了改变的粪便微生物群，但 PI-IBS 患者的微生物群组成仍未得到描述。
描述 PI-IBS 患者的微生物组成，并研究粪便微生物群与患者临床特征之间的关联。
使用系统发育微阵列和选定的 qPCR 检测方法，我们分析了来自五个研究组的 57 名受试者的粪便微生物群差异：诊断为 PI-IBS 的患者、6 个月后仍有肠功能障碍或无 IBS 症状的胃肠炎患者、IBS-D 患者和健康对照。此外，通过将微生物谱与免疫标志物、生活质量指标和直肠活检中的宿主基因表达相关联，研究了粪便微生物群与健康之间的关联。
微生物组分析显示了 27 个属样群组的细菌谱，提供了微生物失调指数（IMD），它显著分离了患者组和对照组。在该图谱中，厚壁菌门的几个成员在患者中增加了 12 倍，而健康对照组的未培养梭菌则增加了 35 倍。我们显示 IMD 与几个宿主基因途径的表达之间存在相关性，包括氨基酸合成、细胞连接完整性和炎症反应，表明 IBS 中上皮屏障功能受损。
PI-IBS 患者的粪便微生物群与健康对照组不同，与 IBS-D 患者相似，提示存在共同的病理生理学。此外，我们的分析表明，各种宿主-微生物的关联可能是由肠胃炎引发的肠道症状的基础。
