Altered fecal bacterial composition correlates with disease activity in inflammatory bowel disease and the extent of IL8 induction

Purpose of the study: In this study we investigated the presence and relative abundance of important genera of the gut microbiota in IBD patients and their role in induction of IL8 in a cell culture model. Patients and methods: Stool samples of IBD patients and healthy controls were collected and relative diversity of thirteen bacterial families was measured using quantitative real-time PCR assay. Moreover, filtrate of the stool samples was used for treatment of HT-29 cell line to analyze involvement of diversity of the fecal bacterial communities in the extent of IL8 induction. Results: Bacteroides, Faecalibacterium prausnitzii, Prevotella spp. and Methanobrevibacterium were significantly less abundant in IBD patients (UC, N=22; CD, N=7) compared with control group (N=29). Increase in relative amounts of Haemophilus,Streptococcus spp. and H. pylori were detected in IBD patients, which was not statistically significant. Relative decrease in amount of Bacteroides spp. Faecalibacterium prausnitzii, and Prevotella spp. were found in UC patients with disease activity score greater than 4; however, higher levels of Streptococcus and Haemophilus were detected in the patients who were at flares. A relationship between the reduction of Haemophilus spp. and higher BMI was shown in IBD patients. Expression of IL8 was significantly higher in the treated cells by the fecal inoculates of IBD patients. Increase in relative amounts of Enterobacteriacea showed a correlation with the higher level of IL8 induction in both groups. Conclusions: These results showed that changes in the fecal microbiota composition could affect disease activity, BMI, and IL8 induction. (C) 2019 Elsevier Masson SAS. All rights reserved.