Duodenal microbiome in patients with or without Helicobacter pylori infection

Abstract

Background Intestinal microbiota are recognized as an organ with important physiological functions whose alterations have been associated with common diseases including inflammatory intestinal conditions, malnutrition, type‐2 diabetes, and cardiovascular diseases. The composition and function of the microbiota in the distal part of the intestine has been mainly described, while there is limited information on the small intestine microbiota. The objective of the present study was to describe the duodenal microbiome in individuals with dyspepsia in the presence or absence of Helicobacter pylori gastric infection. Materials and Methods Thirty‐eight biopsies from the proximal duodenum of uninfected and 37 from H pylori‐infected individuals were analyzed. Microbiota composition was assessed by PCR amplification and sequencing of 16S rRNA and ITS genes; sequences were analyzed with QIIME2. Results and Conclusions At the phyla level, Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, and Fusobacteria were predominant in the mucosal associated duodenal microbiota (MAM); at the genera level, we observed the predominance of Ralstonia, Streptococcus, Pseudomonas, Haemophilus, Herbaspirillum, Neisseria, and Veillonella. Microbiota α‐diversity was higher in H pylori‐infected individuals than in non‐infected ones. In terms of β‐diversity metrics, there was a statistically significant difference between groups. Also, relative abundance of Haemophilus, Neisseria, Prevotella pallens, Prevotella 7, and Streptococcus was greater in H pylori‐infected patients. In infected patients, several types of H pylori were present in duodenal MAM. Finally, the majority of duodenal samples had fungi sequences; the most common taxa observed were Recurvomyces followed by Ascomycota and Basidiomycota.

Alterations of the duodenal mucosal microbiome in patients with metabolic dysfunction-associated steatotic liver disease

“…In the present study, Proteobacteria and Firmicutes were the two major phyla in the mucosa of the descending duodenum in both groups. Compared with duodenal luminal microbiota where Firmicutes and Bacteroidetes are the two major phyla 22 , 23 , the findings from the current study were consistent with previous studies that Proteobacteria and Firmicutes are major phyla in the duodenal mucosa 17 , 24 . However, some previous studies on duodenal mucosa-associated microbiota have reported Firmicutes to be the phylum with the highest relative abundance 25 , 27 , which is inconsistent with the results of the present study.…”

“…Previous studies on duodenal microbiota have sampled various sites within the portions of the duodenum. In addition, some studies sampled duodenal aspirates to investigate luminal microbiota 22 , 23 , while others sampled mucosal tissue to investigate mucosa-associated microbiota 17 , 24 , 25 . Recently, Constante et al 26 reported that gut location is a key determinant of duodenal microbiota composition and predicted function in celiac disease.…”

“…Aging 38 , smoking 39 , PPI use 40 , and H. pylori infection 23 , 24 are known to affect duodenal microbiota. However, in the present study, none of these variables affected the alpha- or beta-diversity of duodenal microbiota (Supplementary Fig.…”

Duodenal microbiota and weight-loss following sleeve gastrectomy and Roux-en-Y gastric bypass – a pilot study

“…We did not have access to the information about H. pylori presence in the patients and it was shown in the previous research that it might influence the microbiota composition with the increase of alpha and beta-diversity. On the other hand, the pattern of microbiota composition did not differ significantly in the infected patients [ 30 ]. Furthermore, eradication therapy may also influence the microbiota composition with the increase of Proteobacteria .…”

CagA+Helicobacter pylori, Not CagA–Helicobacter pylori, Infection Impairs Endothelial Function Through Exosomes-Mediated ROS Formation

“…In addition, gut microbiota plays an important role in the development of atherosclerosis, and there is a relationship between gastric and intestinal microbiome and H. pylori infection. It has been demonstrated that there are significant differences in the diversity and number of gut microbiota between H. pylori infected and uninfected individuals ( 38 , 39 ). It will be important to determine if CagA + H. pylori infection could impair the population and balance of gut microbiota more than CagA – H. pylori infection, thus leading to endothelial dysfunction and atherosclerosis.…”