Genetic Predisposition for Helicobacter pylori Infection-The Jury Is Still Out!

Helicobacter pylori Burden in the United States According to Individual Demographics and Geography: A Nationwide Analysis of the Veterans Healthcare System

BACKGROUND & AIMS

There are no contemporary large-scale studies evaluating the burden of Helicobacter pylori in the United States according to detailed demographics. The primary objective was to evaluate H pylori positivity in a large national healthcare system according to individual demographics and geography.

METHODS

We conducted a nationwide retrospective analysis of adults in the Veterans Health Administration who completed H pylori testing between 1999 and 2018. The primary outcome was H pylori positivity overall, as well as according to zip code-level geography, race, ethnicity, age, sex, and time period.

RESULTS

Among 913,328 individuals (mean, 58.1 years; 90.2% male) included between 1999 and 2018, H pylori was diagnosed in 25.8%. Positivity was highest in non-Hispanic black (median, 40.2%; 95% confidence interval [CI], 40.0%-40.5%) and Hispanic (36.7%; 95% CI, 36.4%-37.1%) individuals and lowest in non-Hispanic white individuals (20.1%; 95% CI, 20.0%-20.2%). Although H pylori positivity declined in all racial and ethnic groups over the timeframe, the disproportionate burden of H pylori in non-Hispanic black and Hispanic compared with non-Hispanic white individuals persisted. Approximately 4.7% of the variation in H pylori positivity was explained by demographics, with race and ethnicity accounting for the vast majority.

CONCLUSIONS

The burden of H pylori is substantial in the United States among veterans. These data should (1) motivate research aimed at better understanding why marked demographic differences in H pylori burden persist so that mitigating interventions may be implemented and (2) guide resource allocation to optimize H pylori testing and eradication in high-risk groups.

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

Microbiome-Metabolomics Analysis of the Impacts of Cryptosporidium muris Infection in BALB/C Mice

Cryptosporidium is a leading cause of diarrheal disease and mortality in young children worldwide. Cryptosporidium invades small intestinal epithelial cells and forms a unique intracellular niche, a process that may alter gut microbes and their production metabolites. However, the mechanism of interactions between gut microbes, metabolites, and parasites is poorly understood. Here, we first characterized the impacts of Cryptosporidium infection on gut microbiota using a microbiome-to-metabolome association study. BALB/c mice were gavaged with Cryptosporidium muris, and fecal samples were collected at 0, 7, 14, 21, and 28 days postinfection (dpi) to observe changes in the intestinal microbes of the body during parasite infection. The infected group had a significantly increased relative abundance of bacterial taxa, such as Lachnospiraceae and Prevotella (P < 0.05), associated with the biosynthesis of short-chain fatty acids (SCFAs). Metabolites related to the metabolic pathways, steroid hormone biosynthesis, and biosynthesis of unsaturated fatty acids pathway were upregulated at 7 dpi, indicating that related metabolites in the biosynthesis of unsaturated fatty acids may be essential for C. muris reproduction in vivo. The metabolites involved in metabolic pathways, bile secretion, and primary bile acid biosynthesis were upregulated at 14 dpi, and we speculate that these metabolites may be critical to the growth and development of Cryptosporidium oocysts in the host. Correlation analysis revealed that Firmicutes bacteria are significantly associated with α-linolenic acid metabolism pathways (P< 0.05). The gut microbiota changes dynamically, and the metabolites involved in fatty acid and bile acid biosynthesis may play important roles during cryptosporidiosis. Details of the gut microbiota and the metabolome after infection with Cryptosporidium may aid in the discovery of specific diagnostic markers and help us understand the changes in parasite metabolic pathways. IMPORTANCE Cryptosporidiosis is a gastrointestinal disease in humans and animals caused by the protozoan parasite Cryptosporidium. Control and treatment of the disease is challenging due to the lack of sensitive diagnostic tools and effective chemotherapy. The dynamics of gut microbiota and metabolites during Cryptosporidium infection may be the key to finding drugs and targets for parasite infection control. Our results indicate that C. muris infection can disrupt gut microbiota and metabolites, resulting in decreased bacterial abundance at the parasitic site. Unsaturated fatty acid pathway biosynthesis-related metabolites are significantly elevated at the patent period. Interestingly, the metabolite pathway that significantly elevated during peak parasite growth was bile acid, the metabolites of which may be important for the circulation of infection of Cryptosporidium oocysts in the host. The enhancing effects of short-chain fatty acid and bile acid metabolism on the growth and development of Cryptosporidium proposed in this study may provide a theoretical basis for future research on novel drugs and vaccines against this intestinal parasite.