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Characterization of the Gastric Microbiota in a Pediatric Population According to Helicobacter pylori Status
Laura Llorca1, Guillermo Pérez-Pérez, Pedro Urruzuno
1From the *Department of Microbiology, Hospital Universitario La Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain; †Department of Medicine and Microbiology, New York University Langone Medical Center, New York, New York; ‡Department of Pediatrics, Hospital Universitario Doce de Octubre, and §Department of Pediatrics. Hospital Universitario Niño Jesús. Madrid, Spain; ¶Department of Genomics and Health, FISABIO Foundation, Center for Advanced Research in Public Health, Valencia, Spain; and ‖Department of Preventive Medicine, Public Health and Microbiology, Medical School, Autonomous University of Madrid, Spain.
Insights
Helicobacter pylori colonization significantly reduces gastric microbial diversity in children. H. pylori dominates the stomach, decreasing beneficial bacteria and richness in pediatric patients.
Area of Science:
- Microbiology
- Pediatric Gastroenterology
- Human Microbiome
Background:
- Helicobacter pylori infection affects 50% of the global population, increasing the risk of gastric diseases.
- Understanding the impact of H. pylori on the pediatric gastric microbiome is crucial for disease management.
Purpose of the Study:
- To compare the gastric microbiota composition in pediatric patients with and without H. pylori colonization.
- To investigate the relationship between H. pylori and gastric microbial diversity and abundance in children.
Main Methods:
- Gastric biopsies from 51 children (18 H. pylori positive, 33 negative) undergoing endoscopy were analyzed.
- Quantitative PCR was used to quantify H. pylori, and V4-16S rRNA gene sequencing studied the gastric microbiome.
- Microbiota analysis included bacterial richness, diversity (alpha and beta diversity), and taxonomic profiling.
Main Results:
- H. pylori-positive children exhibited significantly lower bacterial richness and diversity compared to H. pylori-negative children.
- H. pylori dominated the gastric microbiota in positive cases (66.3% relative abundance), while H. pylori-negative cases showed greater diversity.
- Specific bacterial classes like gammaproteobacteria and betaproteobacteria were more abundant in H. pylori-negative patients, whereas epsilonproteobacteria predominated in positive cases.
- H. pylori-positive patients were more frequently underweight (BMI <18.5) and had lower alpha diversity with active superficial gastritis.
Conclusions:
- H. pylori colonization significantly alters the pediatric gastric microbiota, leading to reduced diversity and richness.
- The presence of H. pylori tends to dominate the gastric microbial community in children.
- H. pylori-negative children harbor a more diverse gastric microbiota with a higher abundance of specific bacterial classes.
Background:
Helicobacter pylori colonizes the human stomach of approximately 50% of the world's population, and increases the risk of several gastric diseases. The goal of this study is to compare the gastric microbiota in pediatric patients with and without H. pylori colonization.
Methods:
We studied 51 children who underwent gastric endoscopy because of dyspeptic symptoms (18 H. pylori positive and 33 negative). Gastric biopsies were obtained for rapid urease test, culture, histology and DNA extraction. H. pylori was quantified by quantitative polymerase chain reaction and the gastric microbiome studied by V4-16S ribosomal RNA gene high-throughput sequencing.
Results:
Bacterial richness and diversity of H. pylori-positive specimens were lower than those of negative, and both groups were clearly separated according to beta diversity. Taxonomic analysis confirmed that H. pylori-positive subjects had a higher relative abundance of Helicobacter genus (66.3%) than H. pylori-negative subjects (0.45%). Four phyla (proteobacteria, bacteroidetes, firmicutes and actinobacteria) accounted for >97% of all reads in both groups. Within proteobacteria, gamma- and betaproteobacteria were the most abundant for H. pylori-negative patients, whereas epsilonproteobacteria was for H. pylori positive. H. pylori-positive patients were associated with low body mass index. In the group of underweight patients (body mass index, <18.5), there were 46.1% of H. pylori-positive patients compared with 24% in the nonunderweight group (P = 0.049). Patients with active superficial gastritis in H. pylori-positive patients had the lowest alpha diversity (P = 0.035).
Conclusions:
We characterized the gastric microbiota for the first time in children with and without H. pylori and observed that when H. pylori is present, it tends to dominate the microbial community. In the H. pylori-negative patients, there was more relative abundance of gammaproteobacteria, betaproteobacteria, bacteroidia and clostridia classes and a higher bacterial richness and diversity.
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