Objective  The aim of this study was to analyze the difference of intestinal microbiota in patientswith moderately severe ulcerative colitis (UC) treated with or without glucocorticoid (GC), and explore the predictive value for the response to intravenous GC medication.

  Methods  The clinical data of outpatients and inpatients with moderately severe UC treated between November 1, 2016 and June 30, 2018 in the Department of Gastroenterology, Peking Union Medical College Hospital were retrospectively collected and analyzed. Patients were divided into GC-exposed group and non GC-exposed group based on whether they were exposed to GC when the fecal sample was collected. Patients from non GC-exposed group who received a full-dose of intravenous GC treatment were divided into GC-effective group and GC-refractory group according to the response after the 3-day treatment. The intestinal microbiota from fecal samples of the UC patient was detected by 16S rRNA gene amplicon sequencing method. α diversity was estimated using the Shannon index. Metastats analysis was employed in multiple comparisons of the microbiota composition.

  Results  Totally 35 moderately severe UC patients were enrolled in this study, among which 20 were non GC-exposed and the other 15 were GC-exposed. Thirteen patients from the non GC-exposed group received a full-dose of intravenous GC treatment after the collection of fecal samples, and 8 of them were GC-effective, while the other 5 were GC-refractory. Patients exposed to GC or not showed little difference in intestinal microbiota α divesity(Shannon index:non GC-exposed group 3.57±0.73, GC-exposed group 3.03±1.15, P=0.123) or microbiota composition. Compared with the GC-effective group (Shannon index 3.69±0.61), the microbiota α diversity of the GC-refractory group (Shannon index 3.15±1.01) was not significantly different (P=0.248). Based on the microbiota composition, the relative abundance of Genus lactobacillus (GC-refractory 0.0015±0.0000, GC-effective 0.0141±0.0002, P=0.010) and Genus bifidobacterium(GC-refractory 0.0178±0.0005, GC-effective 0.1716±0.0382, P=0.011) was significantly lower in the GC-refractory group while that of Genus escherichia-shigella(GC-refractory 0.4161±0.0750, GC-effective 0.1093±0.0173, P=0.008) and Genus prevotella 9 (GC-refractory 0.0176±0.0004, GC-effective 0.0018±0.0000, P=0.044) was significantly higher.

  Conclusions  The α diversity or composition of intestinal microbiota of patients with moderately severe UC may not be correlated with GC treatment. It is possible that pre-treated microbiota composition is related to the response to the intravenous GC treatment.