Analysis of gastric microbiota by next generation sequencing

Abstract

Introduction: Little is known about the role of gastric microbiota except for Helicobacter pylori (HP) in human health and disease. We compared the differences of human gastric microbiota according to gastric cancer or control and HP infection status and assessed the role of bacteria other than HP. Materials and methods: Gastric microbiota of 63 antral mucosa, 18 corpus mucosa samples were analyzed by barcoded 454-pyrosequencing of the 16S rRNA gene. Antral samples were divided into the four subgroups based on HP positivity in pyrosequencing and presence of cancer. The analysis was focused on bacteria other than HP, especially, nitrosating or nitrate reducing bacteria (NB). The changes of NB in antral mucosa of 16 subjects were followed-up. Results: The number of NB other than HP (non-HP-NB) was two times higher in the cancer groups than control groups but it did not reach statistical significance. The number of non-HP-NB tends to increase over time, but this phenomenon was prevented by HP eradication in the HP-positive control group, but not in the HP-positive cancer group. Discussion: We found out HP plays more important role than other bacteria in the gastric carcinogenesis.