P056 Gut microbiota characterisation in South Asian IBD patients resident in the UK

Abstract

Background: The pathogenesis of inflammatory bowel disease (IBD) is understood to be a result of a complex interplay between genetics, host immune response and gut microbiota. There is however emerg-ing data to highlight the role of the environment as supported by the evidence of extensive geographic variation in IBD and migrant studies in the South Asian population. The distinct genetic background as well as the lack of certain risk loci in South Asian IBD patients in contrast to their Caucasian counterparts, and the emergence of Western diet and lifestyle highlight a crucial role of the environment in disease pathogenesis. As the gut microbiota has been shown to be different in the native South Asian population compared to those in developed countries, we aimed to investigate if there were ethnic differences in dysbiosis in IBD patients. Methods: We recruited ten Caucasian (8 with ulcerative colitis, 2 with Crohns; 2 had moderately active disease) and six South Asian (5 with ulcerative colitis, 1 with Crohns; 2 had moderately active dis-ease) patients with IBD attending routine out-patient appointments in to the study. Patient characteristics and disease demographic data was collected along with a stool sample. Microbial DNA was extracted using a modified method of the QIAamp Stool mini kit. To analyse community structure, we amplified the V3-V4 hyper-variable region of the 16S rRNA gene from faecal DNA, using barcoded se-quencing primers. These products were sequenced using the Illumina MiSeq and data analysis was performed using the QIIME pipeline and GreenGenes database to compare differences in microbial composition and diversity between. Results: We found no differences in the microbial diversity nor phy-lae and genera in luminal gut microbiota between South Asian and Caucasian patients with IBD. This observation did not vary regardless of patient and disease characteristics or medications. Similar to previous observations both groups of patients with IBD demonstrated reduced bacterial diversity and an expansion in Proteobac-teria, Bacteroides and Clostridiales along with a decrease in Firmi-cutes. The Firmicutes to Bacteroides ratio was characteristically low as expected in IBD. Conclusions: The gut microbiota in South Asian IBD patients is similar to Caucasian IBD patients. A larger cohort of IBD patients are needed to validate these findings and study the role of travel and diet to changes in gut microbiota associated IBD disease activity.