Alteration in the gastric microbiota of Erosive Reflux Disease and Non-erosive Reflux Disease patients: An indicator for disease progression

Introduction and Aim: Erosive reflux disease (ERD) and Non-erosive reflux disease (NERD) are common gastrointestinal (GI) diseases in primary healthcare facilities that might result in alterations in gastric microflora. The aim was to characterize the altered composition of the gastric microflora in both groups and their effects on normal metabolic pathways. Materials and Methods: A total of 27 individuals, consisting of 18 patients of ERD, 4 patients of NERD, and 5 controls based on the questionnaire data and clinical diagnosis. The gastric microbiome was sequenced using 16S rRNA next-generation sequencing. Gastric microbial diversity and compositions were analyzed using MicrobiomeAnalyst. Functional analysis was performed using PICRUST. Results: Dysbiosis was observed in both ERD and NERD groups when compared to the control. Alpha diversity was found to be significant at the ACE index, at the order (p = 0.0239) and class (p = 0.019) taxonomic levels. The gastric microbiome composition at the genus level of the study groups represented a significant decrease of Gram-positive bacterial genera such as Streptococcus, Corynebacterium, and Granulicatella along with an increase of Gram-negative genera such as Helicobacter and Veillonella. Significant alterations in the metabolic pathways due to this dysbiosis were also predicted for both groups. Conclusion: The alterations in the gastric microflora are caused by both ERD and NERD, these alterations are further associated with a shift in microbial consortia towards the abundance of gram-negative bacterial genera that might lead to the progression of GI diseases to a chronic state.