Objective
Infection with
Helicobacter pylori
(
H pylori
), especially cytotoxin‐associated gene A‐positive (CagA+) strains, has been associated with various gastrointestinal and extragastric diseases. The aim of this study was to characterize
H pylori
‐induced alterations in the gastric and tongue coating microbiota and evaluate their potential impacts on human health.
Design
The gastric mucosa and tongue coating specimens were collected from 80 patients with chronic gastritis, and microbiota profiles were generated by 16S rRNA gene sequencing. Samples were grouped as
H pylori negative
(n = 32), CagA‐negative
H pylori infection
(n = 13), and CagA‐positive
H pylori infection
(n=35). The comparison of bacterial relative abundance was made using a generalized linear model. Functional profiling of microbial communities was predicted with PICRUSt and BugBase. Microbial correlation networks were produced by utilizing SparCC method.
Results
Significant alterations of the gastric microbiota were found in the
H pylori
+/CagA+ samples, represented by a decrease in bacterial diversity, a reduced abundance of
Roseburia
, and increased abundances of
Helicobacter
and
Haemophilus
genera. At the community level, functions involved in biofilm forming, mobile element content, and facultative anaerobiosis were significantly decreased in gastric microbiome of the
H pylori
+ subjects. The presence of CagA gene was linked to an increased proportion of Gram‐negative bacteria in the stomach, thereby contributing to an upregulation of lipopolysaccharide (LPS) biosynthesis. The number of bacterial interactions was greatly reduced in networks of both tongue coating and gastric microbiota of the
H pylori
+/CagA+ subject, and the cooperative bacterial interactions dominated the tongue coating microbiome.
Conclusions
Infection with
H pylori
strains possessing CagA may increase the risk of various diseases, by upregulating LPS biosynthesis in the stomach and weakening the defense of oral microbiota against microorganisms with pathogenic potential.
These results demonstrate that cardiomyocyte apoptosis progressively develops during the early stage after severe burn, which may in part contribute to burn-induced cardiac dysfunction. Myocardial inflammatory responses, evidenced by the increased infiltration of neutrophils, as well as production of TNF-alpha probably because of the activation of p38 MAP kinase, may be involved in burn-induced cardiomyocyte apoptosis.
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