Table 1.

Summary of studies examining the relationships between gastric diseases and gut microbiota

Disease conditions	Country	Sample size	Abundance of H. pylori in diseases	Microbial diversity	Taxon differences	References
NAG, IM, GC	Mexico	5 NAG, 5 IM, 5 GC	↓	α-Diversity: NAG > IM > GC	↑Lactobacillus, Lachnospiraceae from NAG, IM, to GC; ↓Saccaribacteria (TM7), Porphyromonas, Neisseria in GC	Aviles-Jimenez et al. 2014
GC	Korea	34 GC, 29 control	↓	No difference in α- and β-diversity	↑Actinobacteria, Staphylococcus epidermidis in GC; ↑ nitrosating/nitrate‐reducing bacteria in GC (not statistically significant)	Jo et al. 2016
Gastritis, IM, GC	Hong Kong	8 Healthy control, 9 gastritis, 9 IM, 9 GC	↑	↑ Shannon index in GC vs. gastritis ↓ phylogenetic diversity in GC vs. IM	↑Flavobacterium, Klebsiella, Serratia marcescens, Stenotrophomonas, Achromobacter, Pseudomonas, Delftia, Ralstonia, Rhizobium, Elizabethkingia meningoseptica, Methyloversatiis, Gp4, Cytophagaceae in GC	Li et al. 2017
GC, CG	China	6 GC, 5 CG	↓	↓Bacterial richness in GC, but not Shannon diversity index	↑ Neisseria, Alloprevotella, Aggregatibacter, Streptococcus mitis and Porphyromonoas endodontalis in GC; ↓Sphingobium yanoikuyae in GC	Hu et al. 2012
Gastritis, GC	Portugal	Discovery cohort: 81 gastritis, 54 GC	↓	↓α-Diversity in GC	↑Citrobacter, Clostridium, Lactobacillus, Achromobacter, and Rhodococcus in GC patients	Ferreira et al. 2018
GC	China	276 GC	↓	↓α-Diversity in GC	↓Prevotella copri and Bacteroides uniformis; ↑Prevotella melaninogenica, Streptococcus anginosus and Propionibacterium acnes	Liu et al. 2019
GC	Korea	288 GC, 288 control	↑	↓α-Diversity in GC	↑Prevotella copri and Propionibacterium acnes in GC; ↑ Lactococcus lactis in controls	Gunathilake et al. 2019
GC, gastritis, atrophy, IM	Mongolia	48 GC, 120 control (20 healthy, 20 gastritis, 40 atrophy, 40 IM)	↓	α-Diversity: normal > IM > GC > gastritis and atrophy	↑Enterococcus, Lactobacillus, Carnobacterium, Glutamicibacter, Paeniglutamicibacter, Fusobacterium, and Parvimonas in GC	Gantuya et al. 2019
Gastric ulcer, duodenal ulcer	China	Gastric ulcer, duodenal ulcer	↑	↓α-Diversity in DU	↑Helicobacter, Prevotella, Neisseria and Streptococcus	Chen et al. 2018a, b
Gastritis	Germany	Gastritis	↑	No significant difference	↑Helicobacter, Streptococcus	Schulz et al. 2018
Gastritis,IM, GC	China	Gastritis,IM, GC	↓	No significant difference	↑Burkholderia, Enterobacter, and Leclercia, Clostridium, Fusobacterium in non-GC; ↑Lactobacillus in GC, C. colicanis and F. nucleatum represent diagnostic markers for GC	Hsieh et al. 2018
Superficial gastritis, atrophic gastritis, IM, GC	China	21 superficial gastritis, 23 atrophic gastritis, 17 IM, 20 GC	↓	↓α-Diversity in GC and IM vs. SG	↑oral flora, Peptostreptococcus stomatis, Streptococcus anginosus, Parvimonas micra, Slackia exigua and Dialister pneumosintes in GC; ↓Vogesella, Comamonadaceae and Acinetobacter in GC	Coker et al. 2018
Dyspepsia	Spain	Dyspepsia	↓	No significant difference	↑Propionibacterium, Lactobacillus, Streptococcus and Staphylococcus	Delgado et al. 2013
GC, dyspepsia	Sweden	10 GC, 5 dyspepsia	↓	No significant difference	N/A	Dicksved et al. 2009
GC, dyspepsia	Singapore and Malaysia	12 GC, 20 dyspepsia	↓	↑α-Diversity in GC	↑Lactococcus, Veilonella, and Fusobacteriaceae (Fusobacterium and Leptotrichia) in GC	Castaño‐Rodríguez et al. 2017
HP infection	India	HP infection suspected	↑	↑α-Diversity	↑Helicobacter,Lactobacillus, Halomonas and Prevotella	Das et al. 2017
HP infection	China	HP infection suspected	↑	↓α-Diversity	↓Stenotrophomonas maltophilia, Stenotrophomonas unclassified, Variovorax unclassified, Chryseobacterium unclassified, Comamonas unclassified, and Pseudomonas stutzeri	Wang et al. 2022

GC gastric cancer, CG chronic gastritis, NAG non-atrophic gastritis, IM intestinal metaplasia, N/A not available. The “↑” arrow indicates the increase in H.pylori abundance/alpha diversity/ microbial diversity of the diseases and the “↓” indicates the decrease in H.pylori abundance/alpha diversity/ microbial diversity of the diseases