Dig Liver Dis. 2021 Dec;53(12):1580-1587. doi: 10.1016/j.dld.2021.05.005.
Fig. 1. Flowchart of included patients and biopsy samples.
Table 1. Main features of the study population.
Fig. 2. Alpha-diversity of gastric microbiota in the corpus mucosa: comparison between operational taxonomic units (OTUs) (13.333 reads) in cases with corpus atrophic gastritis and controls with a histologically normal corpus mucosa (the figure on the top). The alpha-diversity was represented by a box-and-whisker plot. The bottom and top of the box were the first and third quartiles and the band inside the box was the median. The ends of the whiskers represented the minimum and maximum of all the data of the sample. A statistically significant difference was shown (p < 0.0093). Shannon index H was 3.0 in cases with corpus atrophic gastritis and 3.3 in controls (p < 0.05).
Alpha-diversity of gastric microbiota in the antral mucosa: comparison between operational taxonomic units (OTUs) (13.333 reads) in cases with corpus atrophic gastritis and controls with a histologically normal corpus mucosa (the figure on the bottom). A statistically significant difference was not yielded (p < 0.1110). Shannon index H was 3.0 in cases with corpus atrophic gastritis and 3.3 in controls (p < 0.05).
Table 2. Taxonomy at the genus level in corpus atrophic gastritis cases and controls. The corresponding phyla are also indicated. Only those taxa showing a statistically significant difference between cases and controls and a mean percentage of >0.01 were reported. Absolute and relative differences expressed in percentage were reported to give an insight into how these taxa impact the total microbial community.
Fig. 3. Principal Coordinates Analysis (PCoA) computed by weighted Unifrac (branch lengths weighted by relative abundances) to obtain both. sequence and abundance information. A clear separate clustering of cases with CAG (blu circles) with respect to controls (red circles) thus indicating two different microbial communities in the two groups (p < 0.05 by Permanova).
<Abstract>
Background: In corpus atrophic gastritis (CAG), hypochlorhydria makes plausible the overgrowth of intragastric bacteria, whose role in gastric carcinogenesis is under debate.
Aims: To characterize the antrum/corpus composition of the gastric bacterial microbiota in CAG patients compared to controls without CAG.
Methods: A cross-sectional monocentric study on consecutive patients with known histological diagnosis of CAG undergoing gastroscopy for gastric cancer surveillance and patients without CAG undergoing gastroscopy for dyspepsia or anemia (108 biopsies from 55 patients, median age 61.5). Genomic DNA from one antral and one corpus biopsy from each case (n = 23) and control (n = 32) was extracted. Gastric microbiota was assessed by sequencing hypervariable regions of the 16SrRNA gene.
Results: Bacterial abundance and diversity were significantly lower in CAG cases than in controls (p < 0.001). Firmicutes were more frequent in cases, Bacteroidetes and Fusobacteria in controls (p < 0.0001). Streptococcaceae were more abundant in cases (p < 0.0001), Prevotellaceae in controls (p < 0.0001). The genus Streptococcus was positively correlated with severe OLGA/OLGIM stages linked to a higher risk of gastric cancer.
Conclusion: Gastric bacterial microbiota in CAG showed a reduced abundance and complexity but was characterized by higher colonization of Firmicutes, in particular Streptococcus, increased in subjects with severe atrophy/metaplasia stages at higher risk of gastric cancer.
Dig Liver Dis. 2021 Dec;53(12):1580-1587. doi: 10.1016/j.dld.2021.05.005.
Fig. 1. Flowchart of included patients and biopsy samples.
Table 1. Main features of the study population.
Fig. 2. Alpha-diversity of gastric microbiota in the corpus mucosa: comparison between operational taxonomic units (OTUs) (13.333 reads) in cases with corpus atrophic gastritis and controls with a histologically normal corpus mucosa (the figure on the top). The alpha-diversity was represented by a box-and-whisker plot. The bottom and top of the box were the first and third quartiles and the band inside the box was the median. The ends of the whiskers represented the minimum and maximum of all the data of the sample. A statistically significant difference was shown (p < 0.0093). Shannon index H was 3.0 in cases with corpus atrophic gastritis and 3.3 in controls (p < 0.05).
Alpha-diversity of gastric microbiota in the antral mucosa: comparison between operational taxonomic units (OTUs) (13.333 reads) in cases with corpus atrophic gastritis and controls with a histologically normal corpus mucosa (the figure on the bottom). A statistically significant difference was not yielded (p < 0.1110). Shannon index H was 3.0 in cases with corpus atrophic gastritis and 3.3 in controls (p < 0.05).
Table 2. Taxonomy at the genus level in corpus atrophic gastritis cases and controls. The corresponding phyla are also indicated. Only those taxa showing a statistically significant difference between cases and controls and a mean percentage of >0.01 were reported. Absolute and relative differences expressed in percentage were reported to give an insight into how these taxa impact the total microbial community.
Fig. 3. Principal Coordinates Analysis (PCoA) computed by weighted Unifrac (branch lengths weighted by relative abundances) to obtain both. sequence and abundance information. A clear separate clustering of cases with CAG (blu circles) with respect to controls (red circles) thus indicating two different microbial communities in the two groups (p < 0.05 by Permanova).
<Abstract>
Background: In corpus atrophic gastritis (CAG), hypochlorhydria makes plausible the overgrowth of intragastric bacteria, whose role in gastric carcinogenesis is under debate.
Aims: To characterize the antrum/corpus composition of the gastric bacterial microbiota in CAG patients compared to controls without CAG.
Methods: A cross-sectional monocentric study on consecutive patients with known histological diagnosis of CAG undergoing gastroscopy for gastric cancer surveillance and patients without CAG undergoing gastroscopy for dyspepsia or anemia (108 biopsies from 55 patients, median age 61.5). Genomic DNA from one antral and one corpus biopsy from each case (n = 23) and control (n = 32) was extracted. Gastric microbiota was assessed by sequencing hypervariable regions of the 16SrRNA gene.
Results: Bacterial abundance and diversity were significantly lower in CAG cases than in controls (p < 0.001). Firmicutes were more frequent in cases, Bacteroidetes and Fusobacteria in controls (p < 0.0001). Streptococcaceae were more abundant in cases (p < 0.0001), Prevotellaceae in controls (p < 0.0001). The genus Streptococcus was positively correlated with severe OLGA/OLGIM stages linked to a higher risk of gastric cancer.
Conclusion: Gastric bacterial microbiota in CAG showed a reduced abundance and complexity but was characterized by higher colonization of Firmicutes, in particular Streptococcus, increased in subjects with severe atrophy/metaplasia stages at higher risk of gastric cancer.