The Potential Role of Hypochlorhydria in the Development of Duodenal Dysbiosis: A Preliminary Report

Abstract

In recent years, the role of gastric and duodenal microbiota has acquired increasing importance in the homeostasis of the host, although, to date, most evidence concern the faecal microbiota. Indeed, the gastric, and duodenal microbiota are challenging to study, due to gastric acid, bile, digestive enzymes, and rapid transit time. Specifically, the gastric acid environment may influence their bacterial composition since the acid barrier protects against orally ingested microorganisms and leads to their inactivation before reaching the intestine. The aim of this study was to assess a correlation between intragastric pH and gastric as well as intestinal microbiota of patients with histologic gastric alterations. pH was measured in the gastric juice and the bacterial composition in gastric and duodenal biopsies and faecal samples, was investigated via 16s rRNA gene sequencing. The main result is the direct correlation of duodenal microbiota biodiversity, via alpha diversity measures, with intragastric pH values. In particular, patients with hypochlorhydria showed increased duodenal microbiota biodiversity, higher intragastric pH values being prevalent in patients with chronic atrophic gastritis. Lastly, the latter was also strongly associated to the presence of oral bacteria, like Rothia mucilaginosa, Streptococcus salivarius and Granulicatella adiacens, in the duodenal microbiota. In conclusions, our results suggest a low-acid gastric environment as a contributive factor for duodenal dysbiosis, potentially leading to the development of pathological conditions of the gastrointestinal tract.

A Meta-analysis Reveals Gastric Microbes Associated with Atrophic Gastritis

“…As expected, some synergistic bacteria of Helicobacter promoted the development of AG_P. These identi ed microbes are in agreement with previous studies and may develop into intestinal metaplasia and gastric cancer without prevention [1,2,10,11,17,26,28]. We identi ed Actinomyces as a biomarker for both AG_N and AG_P.…”

“…Bacillus is a genus that is depleted in patients with AG_P and has the potential to be a candidate probiotic for gastritis because of its ability to secret antimicrobial peptides [34]. In particular, Streptococcus is widely regarded as an AG_P-associated bacterium, and species, including Streptococcus mitis/oralis, S. pneumoniae, S. anginosus, and S. salivarius are reportedly associated with AG in H. pyloripositive subjects [10,17,26]. Cutibacterium and Novosphingobium are related to disease progression, but the pathogenic mechanism remains unknown, and the health association of Pseudomonas remains debatable [35][36][37].…”

“…To investigate the reproducible association between the gut microbiome and AG, 16s rRNA data of the gastric mucosa of 537 samples were gathered from 12 different publicly available studies, including controls and patients with AG and SG. The 14 sample locations were Qingdao (China), Hanyang (Korea), Michigan (USA), Porto (Portugal), Inner Mongolia (China), Tumaco (Columbia), Túquerres (Columbia), and Seoul (Korea) (Table 1) [3,[10][11][12][13][14][15][16][17][18][19][20][21]. We rerun the datasets on our platform (Jiangnan University) to obtain a uniform result.…”

Lactobacillus rhamnosus GG supplementation on eradication rate and dyspepsia in Helicobacter pylori infection treated with three-in-one bismuth quadruple therapy

“…The efficacy of LGG in improving the remission of dyspepsia is likely to be ascribed to its influence on Hp-related gastric and duodenal dysbiosis ( O’Hara and Shanahan, 2006 ; Bruno et al, 2018 ; Filardo et al, 2022 ) and, likely, the specific LGG administration schedule may also have positively affected the improvement of dyspepsia. The choice of initiating LGG supplementation 7 days prior to the start of BQT therapy was based on the rationale that LGG possesses anti-inflammatory and inhibitory properties on Hp activity that can improve eradication rates.…”

Impact of Air Pollution on the Composition and Diversity of Human Gut Microbiota in General and Vulnerable Populations: A Systematic Review

“…Intestinal microbiota is more complex than other microbiota niches [ 23 , 24 , 25 ], for instance, the genital microbiota [ 26 , 27 ], and accounts for approximately 10 13 bacteria; the most dominant bacterial phyla are Firmicutes (60–80%) and Bacteroidetes (20–40%), while Proteobacteria , Actinobacteria , Fusobacteria , and Verrucomicrobia are in the minority. Typically, obligate anaerobes (e.g., Bacteroides , Clostridium , Fusobacterium , and Bifidobacterium ) prevail over facultative anaerobes (e.g., Lactobacillus , Escherichia , and Enterococcus ) and the balance of the intestinal microbiota is essential for the integrity of the intestinal epithelial barrier and its functions as well as for the protection against pathogenic challenges.…”