Helicobacter pylori, gastric microbiota and gastric cancer relationship: Unrolling the tangle

Table 1 Taxonomy of the most prevalent gastric microbiota at phylum and genus level

Phylum	Genus
Proteobacteria	Helicobacter, Enterobacteriaceae unknown, Acinetobacter, Pseudomonas, Haemophilus, Agrobacterium, Halomonas, Shewanella, Sphingomonas, Methylobacterium, Aquabacterium
Bacteroidetes	Prevotella, Chryseobacterium
Firmicutes	Streptococcus, Clostridium, Lactobacillus, Staphylococcus, Faecalibacterium, Veillonella, Bacillus, Peptostreptococcus, Selenomonas, Phascolarctobacterium, Gemella, Roseburia, Megamonas, Gemmiger, Lactococcus, Granulicatera, Dialister, Alcaliphylus, Ruminococcus, Blautia
Fusobacteria	Fusobacterium, Leptotrichia
Actinobacteria	Propionobacterium, Corynebacterium, Arthrobacter
Sprirochaetes	Bacteroeides
Acidobacteria	Streptophyta, Sphingobacterium, Pedobacter

Table 2 Relative abundance of gastric microbiota at phylum level among Helicobacter pylori positive and Helicobacter pylori negative patient groups

Phylum	H. pylori-positive			H. pylori-negative
	Minimum	Maximum	Pooled (95%CI)	Minimum	Maximum	Pooled (95%CI)
Proteobacteria	68.7	96.7	88.4 (75.4-95.9)	10.8	52.6	27.9 (12.7-43.9)
Bacteroeidetes	0.8	8.3	3.1 (1.1-6.0)	11.1	30.0	20.8 (12.7-28)
Firmicutes	1.3	14.7	6.2 (1.8-12.9)	16.3	29.9	31.1 (20.5-40.1)
Fusobacteria	0.1	1.6	1.1 (0.2-2.3)	1.1	6.1	3.5 (1.6-6.1)
Actinobacteria	0.2	3.1	1.2 (0.4-2.5)	2.8	46.8	16.7 (2.4-37.2)

Values are expressed as percentages. CI: Confidence interval; H. pylori: Helicobacter pylori.