Difference of colorectal cancer microbial community by metagenomics and culture-based methods.

Abstract

489 Background: Dysbiosis of intestinal microbiota is promoting the development of colorectal cancer (CRC). We confirmed the intestinal microbiota composition from fecal sample of Korean CRC patients. Metagenomic analysis was performed and we isolated single microbes through culture-based method. Methods: CRC fecal samples were collected from 12 individuals. Metagenome Sequencing was based on the 16S rRNA gene amplicon on the Illumina MiSeq platform. The bacteria strains were subcultivated on the agar plate medium in aerobic and anaerobic and further identified by using the 16s rRNA gene sequencing. Results: Bacteria diversity by metagenome analysis was decreased in CRC group compared to control group. In CRC group, relative abundance of Firmicutes and Bacteroidetes were increased while the prevalence of Proteobacteria was decreased. The difference of microbial composition between control and CRC group was found at the genus level. Bacteroides, Parabacteroides of Bacteroidetes have increased and Acinetobacter, Pseudomonas of Proteobacteria have significantly decreased in CRC compared to control group. Using culture method, we isolated diverse bacteria of species level including five strains of Bacteroides; B. ovatus, B. uniformis, B. salyersiae, B. vulgatus and B. xylanisolvens and two strains of Fusobacterium; F. gonidiaformans and F. necrophorum from CRC patients. Conclusions: Metagenome analysis showed the genus Bacteroides, Parabacteroides of the phylum Bacteroidetes has increased and the genus Acinetobacter, Pseudomonas of Proteobacteria decreased in CRC group compared to control group. In addition to, we have isolated various strains associated with CRC by culture-based method.