Association of the gut microbiota with colorectal cancer in a South Asian cohort of patients

BackgroundAs the gut microbiome is thought to play a role in the pathogenesis of colorectal carcinoma (CRC) and affected by the diet and the genetic composition, we sought to investigate the patterns of gut microbiota that associate with CRC in a South Asian cohort of patients with CRC.\n\nMethodologyThe relative abundance of 45 types of gut microbial species were determined in faecal samples of CRC patients (n=24), DM (n=20) and healthy age matched controls (n=44), using a PCR array. Data was analyzed using the specific software for analysis of bacterial DNA quantification.\n\nResultsThe species Bacteroides fragilis (23.9-fold), Bacteroides thetaiotaomicron (8-fold) and Akkermansia muciniphila (5.9 fold) were several-fold over expressed in patients with CRC compared to healthy individuals, whereas bacterial species of the Phylum Proteobactria were under expressed. There was no difference in the abundance of these 3 species of bacteria with tumour stage or gender and age of patients. Aeromonas species, Enterococcus faecium and Shigella dysenteriae (Proteobacteria) were over 100-fold over abundant in those with DM compared to healthy individuals. Although 70.83% of those with CRC also had diabetes, the relative abundance of microbiota in CRC patients were different to those who had diabetes and no CRC.\n\nConclusionsPatients with CRC and DM harbor a markedly different gut microbiota patterns compared to their healthy counterparts. Similar patterns of gut microbial dysbiosis that associate with CRC and DM appear be seen in South Asian populations, compared to Western countries, despite differences in the diet and ethnicity.