The impact of Helicobacter pylori infection, eradication therapy, and probiotics intervention on gastric microbiota in young adults

The Role of Microbiota in Upper Gastrointestinal Cancers

The gut microbiota significantly impacts the development and progression of upper gastrointestinal (GI) cancers, including esophageal and gastric cancers. Microbial dysbiosis contributes to carcinogenesis through mechanisms such as inflammation, immune modulation, and direct DNA damage. Techniques for sampling oral, esophageal, and gastric microbiota vary, with standardization being essential for reliable results. Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) are associated with an enrichment of Gram-negative bacteria, promoting inflammation and cancer progression. Esophageal squamous cell carcinoma (ESCC) also shows distinct microbial patterns, with reduced diversity and increased harmful bacteria like Porphyromonas gingivalis and Fusobacterium nucleatum. In gastric cancer (GC), Helicobacter pylori (HP) and non-HP gastric microbiota play significant roles, with diverse microbial communities contributing to cancer development through nitrate reduction, immune modulation, and inflammation. Emerging evidence highlights the role of non-HP bacteria in promoting carcinogenesis, with specific taxa like Fusobacterium nucleatum and Lactobacillus influencing tumor growth and immune evasion. Further research is needed to elucidate the complex interactions between gut microbiota and upper GI cancers, paving the way for novel diagnostic and therapeutic approaches. Understanding these microbial dynamics offers potential for microbiota-based interventions, improving the early detection, prognosis, and treatment of upper GI cancers. This comprehensive review summarizes the available evidence on the role of microbiota in upper GI oncology and the need for continued exploration in this field.

Impacts of Helicobacter pylori infection and eradication on gastrointestinal microbiota: An up-to-date critical review and future perspectives

ABSTRACT

Helicobacter pylori ( H. pylori ) infects approximately half of the population worldwide and causes chronic gastritis, peptic ulcers, and gastric cancer. Test-and-treat strategies have been recommended for the prevention of H. pylori -associated diseases. Advancements in high-throughput sequencing technologies have broadened our understanding of the complex gastrointestinal (GI) microbiota and its role in maintaining host homeostasis. Recently, an increasing number of studies have indicated that the colonization of H. pylori induces dramatic alterations in the gastric microbiota, with a predominance of H. pylori and a reduction in microbial diversity. Dysbiosis of the gut microbiome has also been observed after H. pylori infection, which may play a role in the development of colorectal cancer. However, there is concern regarding the impact of antibiotics on the gut microbiota during H. pylori eradication. In this review, we summarize the current literature concerning how H. pylori infection reshapes the GI microbiota and the underlying mechanisms, including changes in the gastric environment, immune responses, and persistent inflammation. Additionally, the impacts of H. pylori eradication on GI microbial homeostasis and the use of probiotics as adjuvant therapy are also discussed. The shifts in the GI microbiota and their crosstalk with H. pylori  may provide potential targets for H. pylori -related gastric diseases and extragastric manifestations.

Helicobacter pylori: Routes of Infection, Antimicrobial Resistance, and Alternative Therapies as a Means to Develop Infection Control

Helicobacter pylori (H. pylori) is a Gram-negative, spiral-shaped bacterium that colonizes the gastric epithelium and is associated with a range of gastrointestinal disorders, exhibiting a global prevalence of approximately 50%. Despite the availability of treatment options, H. pylori frequently reemerges and demonstrates increasing antibiotic resistance, which diminishes the efficacy of conventional therapies. Consequently, it is imperative to explore non-antibiotic treatment alternatives to mitigate the inappropriate use of antibiotics. This review examines H. pylori infection, encompassing transmission pathways, treatment modalities, antibiotic resistance, and eradication strategies. Additionally, it discusses alternative therapeutic approaches such as probiotics, anti-biofilm agents, phytotherapy, phototherapy, phage therapy, lactoferrin therapy, and vaccine development. These strategies aim to reduce antimicrobial resistance and enhance treatment outcomes for H. pylori infections. While alternative therapies can maintain low bacterial levels, they do not achieve complete eradication of H. pylori. These therapies are designed to bolster the immune response, minimize side effects, and provide gastroprotective benefits, rendering them suitable for adjunctive use alongside conventional treatments. Probiotics may serve as adjunctive therapy for H. pylori; however, their effectiveness as a monotherapy is limited. Photodynamic and phage therapies exhibit potential in targeting H. pylori infections, including those caused by drug-resistant strains, without the use of antibiotics. The development of a reliable vaccine is also critical for the eradication of H. pylori. This review identifies candidate antigens such as VacA, CagA, and HspA, along with various vaccine formulations, including vector-based and subunit vaccines. Some vaccines have demonstrated efficacy in clinical trials, while others have shown robust immune protection in preclinical studies. Nevertheless, each of the aforementioned alternative therapies requires thorough preclinical and clinical evaluation to ascertain their efficacy, side effects, cost-effectiveness, and patient compliance.

The influence of Helicobacter pylori, proton pump inhibitor, and obesity on the gastric microbiome in relation to gastric cancer development

Helicobacter pylori infection is still the main risk factor for the development of gastric cancer (GC). We explore the scientific evidence for the role of the gastric microbiome beyond Helicobacter pylori (H. pylori) in gastric carcinogenesis. The composition of the gastric microbiome in healthy individuals, in presence and absence of H. pylori infection, in proton pump inhibitor (PPI)-users, obese individuals, and GC patients was investigated. Possible mechanisms for microbial involvement, limitations of available research and options for future studies are provided. A common finding amongst studies was increased levels of Streptococcus, Prevotella, Neisseria, and Actinomyces in healthy individuals or those with H. pylori-negative gastritis. In PPI-users the risk for GC increases with the treatment duration, and the gastric microbiome shifts, with the most consistent increase in the genus Streptococcus. Similarly, in obese individuals, Streptococcus was the most abundant genus, with an increased risk for cardia GC. The genera Streptococcus, Lactobacillus and Prevotella were found to be more prominent in GC patients in multiple studies. Potential mechanisms of non-H. pylori microbiota contributing to GC are linked to lipopolysaccharide production, contribution to inflammatory pathways, and the formation of N-nitroso compounds and reactive oxygen species. In conclusion, the knowledge of the gastric microbiome in GC is mainly descriptive and based on sequencing of gastric mucosal samples. For a better mechanistic understanding of microbes in GC development, longitudinal cohorts including precancerous lesions, different regions in the stomach, and subtypes of GC, and gastric organoid models for diffuse and intestinal type GC should be employed.

Stomach microbiota in gastric cancer development and clinical implications

Gastric cancer (GC) is one of the most common malignancies and a prominent cause of cancer mortality worldwide. A distinctive characteristic of GC is its intimate association with commensal microbial community. Although Helicobacter pylori is widely recognised as an inciting factor of the onset of gastric carcinogenesis, increasing evidence has indicated the substantial involvement of microbes that reside in the gastric mucosa during disease progression. In particular, dysregulation in gastric microbiota could play pivotal roles throughout the whole carcinogenic processes, from the development of precancerous lesions to gastric malignancy. Here, current understanding of the gastric microbiota in GC development is summarised. Potential translational and clinical implications of using gastric microbes for GC diagnosis, prognosis and therapeutics are also evaluated, with further discussion on conceptual haziness and limitations at present. Finally, we highlight that modulating microbes is a novel and promising frontier for the prevention and management of GC, which necessitates future in-depth investigations.

Microbiota in gastrointestinal malignancies

This manuscript provides an overview of the microbiota profile associated with precancerous lesions in the esophagus, stomach, and large bowel. The critical review of the available data reveals significant variability in the methods used for microbiota profiling. This variability may affect the reliable identification of specific biological links between histologically profiled neoplastic diseases and the microbiota population. Overall, this critical review reveals significant links between microbiota communities and the different lesions within the spectrum of the oncogenetic cascade in various epidemiological contexts and anatomical districts.

Unveiling the potential role of micro/nano biomaterials in the treatment of Helicobacter pylori infection

INTRODUCTION

Helicobacter pylori causes stubborn infections and leads to a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. Although antibiotic-based approaches have been widely used against H. pylori, some challenges such as antibiotic resistance are increasing in severity. Therefore, simpler but more effective strategies are needed.

AREAS COVERED

In this review, basic information on functionalized and non-functionalized micro/nano biomaterials and routes of administration for H. pylori inhibition are provided in an easy-to-understand format. Afterward, in vitro and in vivo studies of some promising bio-platforms including metal-based biomaterials, biopolymers, small-molecule saccharides, and vaccines for H. pylori inhibition are discussed in a holistic manner.

EXPERT OPINION

Functionalized or non-functionalized micro/nano biomaterials loaded with anti-H. pylori agents can show efficient bactericidal activity with no/slight negative influence on the host gastrointestinal microbiota. However, this claim needs to be substantiated with hard data such as assessment of the biopharmaceutical parameters of anti-H. pylori systems and the measurement of diversity/abundance of bacterial genera in the host gastric/gut microbiota before and after H. pylori eradication.

Helicobacter pylori and the Human Gastrointestinal Microbiota: A Multifaceted Relationship

Helicobacter pylori is a type of Gram-negative bacteria belonging to the Proteobacteria phylum which is known to cause gastrointestinal disorders such as gastritis and gastric ulcers. Its treatment is based on current eradication regimens, which are composed of combinations of antibiotics such as clarithromycin, metronidazole, levofloxacin and amoxicillin, often combined with a proton pump inhibitor (PPI). With the development of sequencing technologies, it has been demonstrated that not only does the colonization of the gastric and gut environment by H. pylori cause microbial changes, but also the treatment regimens used for its eradication have a significant altering effect on both the gastric and gut microbiota. Here, we review current knowledge on microbiota modulations of current therapies in both environments. We also summarize future perspectives regarding H. pylori infection, the integration of probiotics into therapy and what challenges are being faced on a global basis when we talk about eradication.

Screening Probiotics for Anti-Helicobacter pylori and Investigating the Effect of Probiotics on Patients with Helicobacter pylori Infection

Probiotics are natural microbial agents with beneficial properties such as bacteriostatic and anti-infective properties. Lactobacillus plantarum Q21, Q25 and QA85, were isolated from the Chinese specialty fermented food "Jiangshui" and proved to be highly resistant to Helicobacter pylori (p < 0.0001). In vitro results showed that Q21, Q25 and QA85 strongly inhibited H. pylori and could specifically co-aggregate H. pylori in vitro (more than 56%). Strains have the potential to adhere to cells and hinder H. pylori colonization (p < 0.0001). To assess the anti-H. pylori efficacy of strains in vivo, volunteers were recruited and a self-controlled study of probiotic intervention was conducted. Compared to pre-probiotics, volunteers who took Q21, Q25 and QA85 for 1 month showed significant improvement in discomfort, a significant reduction in GSRS scores (p < 0.05), and modulation of inflammatory response (p < 0.05). Q21, Q25 and QA85 resulted in a decreasing trend of H. pylori load in volunteers (454.30 ± 327.00 vs. 328.35 ± 237.19, p = 0.06). However, the strains were not significantly effective in modulating the imbalance of the gut microbiota caused by H. pylori infection. In addition, strains affect metabolic pathways by increasing the levels of O-Phosphoethanolamine and other related metabolites, which may ameliorate associated symptoms. Therefore, Lactobacillus plantarum Q21, Q25 and QA85 can be regarded as a candidate probiotic preparation that exerts direct or indirect anti-H. pylori effects by inhibiting H. pylori activity and colonization, reducing inflammation and discomfort, maintaining homeostasis in the internal environment, affecting the metabolic pathways and repairing the body barrier. They can play a role in relieving H. pylori infection.

Novel therapeutic regimens against Helicobacter pylori: an updated systematic review

Helicobacter pylori (H. pylori) is a strict microaerophilic bacterial species that exists in the stomach, and H. pylori infection is one of the most common chronic bacterial infections affecting humans. Eradicating H. pylori is the preferred method for the long-term prevention of complications such as chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. However, first-line treatment with triple therapy and quadruple therapy has been unable to cope with increasing antibacterial resistance. To provide an updated review of H. pylori infections and antibacterial resistance, as well as related treatment options, we searched PubMed for articles published until March 2024. The key search terms were "H. pylori", "H. pylori infection", "H. pylori diseases", "H. pylori eradication", and "H. pylori antibacterial resistance." Despite the use of antimicrobial agents, the annual decline in the eradication rate of H. pylori continues. Emerging eradication therapies, such as the development of the new strong acid blocker vonoprazan, probiotic adjuvant therapy, and H. pylori vaccine therapy, are exciting. However, the effectiveness of these treatments needs to be further evaluated. It is worth mentioning that the idea of altering the oxygen environment in gastric juice for H. pylori to not be able to survive is a hot topic that should be considered in new eradication plans. Various strategies for eradicating H. pylori, including antibacterials, vaccines, probiotics, and biomaterials, are continuously evolving. A novel approach involving the alteration of the oxygen concentration within the growth environment of H. pylori has emerged as a promising eradication strategy.

A review for non-antibiotic treatment of Helicobacter pylori: new insight

Gastric ulcers and gastric cancer are brought on by the Helicobacter pylori bacteria, which colonizes under the stomach mucous membrane. Different medication regimens are used to remove it, but the illness returns and becomes more resistant, which lowers the treatment rates. Additionally, this bacterium now exhibits a skyrocketing level of multi-drug resistance, necessitating recurrent therapeutic treatments. The negative effects of synthetic medications in comparison to conventional therapies are another significant factor in favor of non-pharmacological therapy. The most significant side effects of popular anti-gastric ulcer medications include nausea, vomiting, and diarrhea. Stomach ulcers have previously been treated with herbal remedies and complementary treatments like probiotics. When probiotics are ingested, the host experiences several advantages that may be brought about by altering the bacterial flora in the digestive system. Additionally, stronger-acting chemical compounds and plant extracts can be employed to treat patients. In this article, we look at the substances and medications that are utilized in place of synthetic stomach ulcer-curing treatments.

Helicobacter pylori and oral-gut microbiome: clinical implications

More than half of the world's population are colonized with H. pylori; however, the prevalence varies geographically with the highest incidence in Africa. H. pylori is probably a commensal organism that has been associated with the development of gastritis, ulcers, and gastric cancer. H. pylori alone is most probably not enough for the development of gastric carcinoma, but evidence for its association with the disease is high and has, therefore, been classified by the International Agency for Research on Cancer as a Class 1 carcinogen. Bacteroidetes and Fusobacteria positively coexisted during H. pylori infection along the oral-gut axis. The eradication therapy required to treat H. pylori infection can also have detrimental consequences for the gut microbiota, leading to a decreased alpha diversity. Therefore, therapy regimens integrated with probiotics may abolish the negative effects of antibiotic therapy on the gut microbiota. These eradication therapies combined with probiotics have also higher rates of eradication, when compared to standard treatments, and are associated with reduced side effects, improving the patient's compliance. The eradication therapy not only affects gut microbiome but also affects the oral microbiome with robust predominance of harmful bacteria. However, there have been reports of a protective role of H. pylori in Barrett's esophagus, esophageal adenocarcinoma, eosinophilic esophagitis, IBD, asthma, and even multiple sclerosis. Therefore, eradication therapy should be carefully considered, and test to treat policy should be tailored to specific communities especially in highly endemic areas. Supplementation of probiotics, prebiotics, herbals, and microbial metabolites to reduce the negative effects of eradication therapy should be considered. After failure of many eradication attempts, the benefits of H. pylori eradication should be carefully balanced against the risk of adverse effects especially in the elderly, persons with frailty, and intolerance to antibiotics.

The Role of Probiotics in the Eradication of Helicobacter pylori and Overall Impact on Management of Peptic Ulcer: A Study Involving Patients Undergoing Triple Therapy in Bangladesh

Background Helicobacter pylori infection has been identified to cause constantly recurring inflammation, leading to gastrointestinal tract disorders, including carcinoma. The standard triple therapy (STT), used to eradicate H. pylori, includes two antimicrobials and a proton pump inhibitor for two weeks. Other drug regimens have also been developed since H. pylori exhibits antimicrobial resistance. These regimens, including probiotics, have been shown to lower adverse drug reactions (ADR), improve drug adherence, exert bacteriostatic effect, and reduce inflammation. Objective This study intended to explore probiotic intervention for improving eradication rates and mitigating adverse effects while administrating STT.  Methods This prospective study was conducted from May to December, 2021, in the Department of Gastroenterology of Ship International Hospital, Dhaka, Bangladesh, to observe the effects of probiotics inclusion along with STT on H. pylori eradication. A total of 100 patients aged ≥18 years who tested positive for H. pylori were included. The experimental group (n=50) was given STT and probiotics, and the control group (n=50) was given only STT without probiotics for 14 days. Necessary follow-up was done six weeks after treatment. An independent sample t-test, chi-square test, and multiple regression analysis were used for statistical analysis. Result The odds of getting rapid urease test (RUT) negative results from positive were 2.06 times higher (95%CI= 0.95, 3.22, p=0.054) in the experimental group. ADRs were crucially towering in the control group (p=0.045) compared to the probiotics group. The probiotics group had a lower risk of having adverse effects by 0.54 times (95%CI=0.19, 0.84, p=0.032) than the control group. Conclusion Using probiotics and STT together to eradicate H. pylori may lower ADR and improve treatment adherence. It may also help terminate H. pylori infection more effectively. More research is required as H. pylori is very contagious and can ultimately cause life-threatening gastric cancer.

Unraveling the Puzzle: Health Benefits of Probiotics-A Comprehensive Review

A growing number of probiotic-containing products are on the market, and their use is increasing. Probiotics are thought to support the health of the gut microbiota, which in turn might prevent or delay the onset of gastrointestinal tract disorders. Obesity, type 2 diabetes, autism, osteoporosis, and some immunological illnesses are among the conditions that have been shown to possibly benefit from probiotics. In addition to their ability to favorably affect diseases, probiotics represent a defense system enhancing intestinal, nutritional, and oral health. Depending on the type of microbial strain utilized, probiotics can have variable beneficial properties. Although many microbial species are available, the most widely employed ones are lactic acid bacteria and bifidobacteria. The usefulness of these bacteria is dependent on both their origin and their capacity to promote health. Probiotics represent a valuable clinical tool supporting gastrointestinal health, immune system function, and metabolic balance. When used appropriately, probiotics may provide benefits such as a reduced risk of gastrointestinal disorders, enhanced immunity, and improved metabolic health. Most popular probiotics, their health advantages, and their mode of action are the topic of this narrative review article, aimed to provide the reader with a comprehensive reappraisal of this topic matter.

Predictors of Successful First-Line Helicobacter pylori Eradication with Fluoroquinolones in Pakistan: A Prospective Exploration of Demographic and Clinical Factors

Growing antibiotic resistance complicates H. pylori eradication, posing a public health challenge. Inconclusive research on sociodemographic and clinical factors emphasizes the necessity for further investigations. Hence, this study aims to evaluate the correlation between demographic and clinical factors and the success rates of H. pylori eradication. A group of 162 H. pylori-positive patients were allocated randomly to receive either a ten-day moxifloxacin-based triple therapy or a levofloxacin-based sequential therapy. Eradication success was determined through the stool antigen test. Logistic regression analysis was utilized to figure out potential factors that contribute to H. pylori eradication success. Significantly higher H. pylori eradication rates were observed in the middle age group (COR: 3.671, p = 0.007), among females (p = 0.035), those with BMI ≥ 25 (COR: 2.011, p = 0.045), and non-smokers (COR: 2.718, p = 0.018). In multivariate analysis, age and smoking emerged as significant predictors (p < 0.05). Patients with comorbidities, excluding diabetes and hypertension (COR: 4.432, p = 0.019), dyspepsia (COR: 0.178, p < 0.001), and moxifloxacin triple therapy (COR: 0.194, p = 0.000), exhibited higher chances of eradication (p < 0.05). Further research is vital for tailored approaches to enhance eradication success.

Butyric Acid Supplementation Reduces Changes in the Taxonomic and Functional Composition of Gut Microbiota Caused by H. pylori Eradication Therapy

H. pylori eradication therapy leads to significant changes in the gut microbiome, including influence on the gut microbiome's functional potential. Probiotics are one of the most studied potential methods for reducing the microbiota-related consequences of antibiotics. However, the beneficial effects of probiotics are still under discussion. In addition, there are some concerns about the safety of probiotics, emphasizing the need for research of other therapeutic interventions. The aim of our study was to evaluate the influence of butyric acid+inulin supplements on gut microbiota changes (the gut microbiota composition, abundance of metabolic pathways, and gut resistome) caused by H. pylori eradication therapy.

MATERIALS AND METHODS

Twenty two H. pylori-positive patients, aged 19 to 64 years, were enrolled in the study and randomized into two treatment groups, as follows: (1) ECAB-14 (n = 11), with esomeprazole 20 mg, clarithromycin 500 mg, amoxicillin 1000 mg, and bismuthate tripotassium dicitrate 240 mg, twice daily, per os, for 14 days, and (2), ECAB-Z-14 (n = 11), with esomeprazole 20 mg, clarithromycin 500 mg, amoxicillin 1000 mg, and bismuthate tripotassium dicitrate 240 mg, twice daily, along with butyric acid+inulin (Zacofalk), two tablets daily, each containing 250 mg of butyric acid, and 250 mg of inulin, per os, for 14 days. Fecal samples were collected from each subject prior to eradication therapy (time point I), after the end of eradication therapy (time point II), and a month after the end of eradication therapy (time point III). The total DNA from the fecal samples was isolated for whole genome sequencing using the Illumina NextSeq 500 platform. Qualitative and quantitative changes in gut microbiota were assessed, including alpha and beta diversity, functional potential and antibiotic resistance gene profiling.

RESULTS

Gut microbiota alpha diversity significantly decreased compared with the baseline immediately after eradication therapy in both treatment groups (ECAB-14 and ECAB-Z-14). This diversity reached its baseline in the ECAB-Z-14 treatment group a month after the end of eradication therapy. However, in the ECAB-14 treatment arm, a reduction in the Shannon index was observed up to a month after the end of H. pylori eradication therapy. Fewer alterations in the gut microbiota functional potential were observed in the ECAB-Z-14 treatment group. The abundance of genes responsible for the metabolic pathway associated with butyrate production decreased only in the ECAB-14 treatment group. The prevalence of antibiotic-resistant genes in the gut microbiota increased significantly in both treatment groups by the end of treatment. However, more severe alterations were noted in the ECAB-14 treatment group.

CONCLUSIONS

H. pylori eradication therapy leads to taxonomic changes, a reduction in the alpha diversity index, and alterations in the functional potential of the gut microbiota and gut resistome. Taking butyric acid+inulin supplements during H. pylori eradication therapy could help maintain the gut microbiota in its initial state and facilitate its recovery after H. pylori eradication.

Antibiotic Resistance of Helicobacter pylori: Mechanisms and Clinical Implications

Helicobacter pylori is a pathogenic bacterium associated with various gastrointestinal diseases, including chronic gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. The increasing rates of H. pylori antibiotic resistance and the emergence of multidrug-resistant strains pose significant challenges to its treatment. This comprehensive review explores the mechanisms underlying the resistance of H. pylori to commonly used antibiotics and the clinical implications of antibiotic resistance. Additionally, potential strategies for overcoming antibiotic resistance are discussed. These approaches aim to improve the treatment outcomes of H. pylori infections while minimizing the development of antibiotic resistance. The continuous evolution of treatment perspectives and ongoing research in this field are crucial for effectively combating this challenging infection.

Comparison of Helicobacter pylori positive and negative gastric cancer via multi-omics analysis

IMPORTANCE

This is the first clinical research to systematically expound the difference between gastric cancer (GC) individuals with Helicobacter pylori and GC individuals without H. pylori from the perspective of multi-omics. This clinical study identified significant genes, microbes, and fecal metabolites, which exhibited nice power for differentiating GC individuals with H. pylori infection from GC individuals without H. pylori infection. This study provides a crucial basis for a better understanding of eradication therapy among the GC population.

The impact of Helicobacter pylori eradication with vonoprazan-amoxicillin dual therapy combined with probiotics on oral microbiota: a randomized double-blind placebo-controlled trial

Background

Helicobacter pylori infection and eradication have been reported to cause dysbiosis of the oral microbiota. Probiotics are increasingly being used to maintain the balance of the oral microbiota. We aimed to investigate the effects of H. pylori infection, H. pylori eradication with vonoprazan-amoxicillin dual therapy, and probiotics supplementation on the oral microbiota.

Methods

H. pylori positive patients were randomly assigned to a vonoprazan-amoxicillin regimen plus probiotics (BtT group) or the placebo (PT group) for 14 days. H. pylori negative population served as normal controls. Tongue coating samples were collected from 60 H. pylori positive patients at three time points (before H. pylori eradication, after H. pylori eradication, and at confirmation of H. pylori infection cure) and 20 H. pylori negative subjects. 16S rRNA gene sequencing was used to analyze the oral microbiota.

Results

H. pylori was detected in the oral cavity in positive (34/60), negative (7/20), and eradicated (1/60) subjects using high-throughput sequencing. Compared with normal controls, H. pylori positive patients exhibited higher richness (p = 0.012) and comparable diversity (p = 0.075) of oral microbiota. Beta diversity and KEGG analysis showed oral flora composition and function differences in H. pylori positive and negative subjects. Alpha diversity dramatically decreased after H. pylori eradication and modestly increased with confirmation of H. pylori eradication. Beta diversity and LEfSe analysis revealed distinct structures, and KEGG analysis showed distinct signaling pathways of tongue coating flora at three time points. There was a significant reduction of Firmicutes and Lactobacillus after H. pylori erdication. The PT group and BtT group had identical compositional and functional differences of oral microbiota at three time points.

Conclusion

No substantial link existed between oral and stomach H. pylori, while removing gastric H. pylori helped eliminate oral H. pylori. H. pylori infection and vonoprazan-amoxicillin dual therapy affected oral microbiota diversity, structure, and function. H. pylori eradication demonstrated a suppressive impact on the proliferation of oral pathogens, specifically Firmicutes and Lactobacillus. Nevertheless, probiotics supplementation did not reduce the oral microbial disturbance caused by H. pylori eradication.

Clinical trial registration

https://www.chictr.org.cn/, identifiers CHICTR2200060023.

Efficacy and safety of probiotic-supplemented bismuth quadruple therapy for the treatment of Helicobacter pylori infection: a systematic review and meta-analysis

OBJECTIVE

We performed a meta-analysis to determine whether the addition of probiotics to the bismuth quadruple therapy (BQT) for Helicobacter pylori would improve the incidence of eradication and reduce that of side effects.

METHODS

Randomized controlled trials matching the inclusion criteria were collected from PubMed, Embase, Web of Science, and The Cochrane Central Register of Controlled Trials. A Mantel-Haenszel random-effects model was used to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for the incidences of eradication rate, side effects as a whole, diarrhea, and other side effects.

RESULTS

Ten studies were selected for inclusion in the meta-analysis. The pooled RRs for the eradication rates in intention-to-treat and per-protocol analyses of the probiotic group vs. the control group were 1.07 (95% CI: 1.02-1.11) and 1.04 (95% CI: 1.00-1.07), respectively. Probiotic supplementation reduced the incidences of side effects (RR 0.58, 95% CI: 0.37-0.91), diarrhea (RR 0.41, 95% CI: 0.25-0.67), and bitter taste (RR 0.63, 95% CI: 0.40-0.99).

CONCLUSIONS

The results of this meta-analysis support the use of probiotics in combination with BQT in the clinical management of patients with H. pylori infection.

Rise of the guardians: Gut microbial maneuvers in bacterial infections

AIMS

Bacterial infections are one of the major causes of mortality globally. The gut microbiota, primarily comprised of the commensals, performs an important role in maintaining intestinal immunometabolic homeostasis. The current review aims to provide a comprehensive understanding of how modulation of the gut microbiota influences opportunistic bacterial infections.

MATERIALS AND METHODS

Primarily centered around mechanisms related to colonization resistance, nutrient, and metabolite-associated factors, mucosal immune response, and commensal-pathogen reciprocal interactions, we discuss how gut microbiota can promote or prevent bacterial infections.

KEY FINDINGS

Opportunistic infections can occur directly due to obligate pathogens or indirectly due to the overgrowth of opportunistic pathobionts. Gut microbiota-centered mechanisms of altered intestinal immunometabolic and metabolomic homeostasis play a significant role in infection promotion and prevention. Depletion in the population of commensals, increased abundance of pathobionts, and overall decrease in gut microbial diversity and richness caused due to prolonged antibiotic use are risk factors of opportunistic bacterial infections, including infections from multidrug-resistant spp. Gut commensals can limit opportunistic infections by mechanisms including the production of antimicrobials, short-chain fatty acids, bile acid metabolism, promoting mucin formation, and maintaining immunological balance at the mucosa. Gut microbiota-centered strategies, including the administration of probiotics and fecal microbiota transplantation, could help attenuate opportunistic bacterial infections.

SIGNIFICANCE

The current review discussed the gut microbial population and function-specific aspects contributing to bacterial infection susceptibility and prophylaxis. Collectively, this review provides a comprehensive understanding of the mechanisms related to the dual role of gut microbiota in bacterial infections.

Probiotics and autoprobiotics for treatment of Helicobacter pylori infection

The article discusses various approaches for probiotic treatment of Helicobacter pylori (H. pylori) infection: Probiotics as an adjuvant treatment in the standard eradication therapy; probiotic strains as a monotherapy; and autoprobiotics as a monotherapy. Autoprobiotics refer to indigenous bifidobacteria, lactobacilli, or enterococci isolated from a specific individual, intended to restore his/her microbiota and improve his/her health. The potential mechanisms of probiotic action against H. pylori include correction of the gut microbiota, immunological effects (enhancement of humoral and cellular immunity, and reduction of oxidative stress), direct antagonistic effects against H. pylori (such as colonization resistance and bacteriocin synthesis), and stimulation of local immunological protection (strengthening of the mucous protective barrier and reduction of gastric mucosa inflammation). The incorporation of probiotics into comprehensive eradication therapy shows promise in optimizing the treatment of H. pylori infection. Probiotics can enhance the eradication rates of H. pylori, reduce the occurrence and severity of side effects, and improve patient compliance. Probiotic or autoprobiotic monotherapy can be considered as an alternative treatment approach in cases of allergic reactions and insufficient effectiveness of antibiotics. We recommend including probiotics as adjunctive medications in anti-H. pylori regimens. However, further randomized multicenter studies are necessary to investigate the effects of probiotics and autoprobiotics against H. pylori, in order to gain a better understanding of their mechanisms of action.

The Eradication of Helicobacter pylori Was Significantly Associated with Compositional Patterns of Orointestinal Axis Microbiota

BACKGROUND

Helicobacter pylori (H. pylori) is significantly linked to various diseases that seriously impact human health, such as gastric ulcers, chronic gastritis and gastric adenocarcinoma.

METHODS

The compositional shifts in bacterial communities of the orointestinal axis were surveyed pre/post-eradication of H. pylori. In total, 60 samples, including stool and salivary specimens, were collected from 15 H. pylori-positive individuals (HPP) before beginning and 2 months after receiving the eradication therapy. The V3-V4 regions of the 16S rRNA gene were sequenced using MiSeq.

RESULTS

Overall, oral microbiomes were collectively more diverse than the gut microbiomes (Kruskal-Wallis; p = 3.69 × 10^-5). Notably, the eradication of H. pylori was associated with a significant reduction in the bacterial diversity along the orointestinal axis (Wilcoxon rank sum test; p = 6.38 × 10^-3). Interestingly, the oral microbiome of HPP showed a positive correlation between Proteobacteria and Fusobacteria, in addition to a significant predominance of Streptococcus, in addition to Eubacterium_eligens, Haemophilus, Ruminococcaceae, Actinomyces and Staphylococcus. On the other hand, Fusobacterium, Veillonella, Catenibacterium, Neisseria and Prevotella were significantly enriched upon eradication of H. pylori. Generally, Bacteroidetes and Fusobacteria positively coexisted during H. pylori infection along the orointestinal axis (r = 0.67; p = 0.0006). The eradication of H. pylori was positively linked to two distinctive orotypes (O3 and O4). Orotype O4 was characterized by a robust abundance of Veillonella and Fusobacteria. The gut microbiomes during H. pylori infection showed a remarkable predominance of Clostridium_sensu_stricto_1 and Escherichia_Shigella. Likewise, Bifidobacterium and Faecalibacterium were significantly enriched upon eradication of H. pylori.

CONCLUSIONS

Finally, the impact of eradication therapy clearly existed on the representation of certain genera, especially in the oral microbiome, which requires particular concern in order to counteract and limit their subsequent threats.

The Potential of Alternative Therapies and Vaccine Candidates against Helicobacter pylori

Alternative therapies and vaccination are essential to combat the emergence of multidrug-resistant Helicobacter pylori and to prevent the development of gastroduodenal diseases. This review aimed to systematically review recent studies on alternative therapies, i.e., probiotics, nanoparticles, and natural products from plants, as well as recent progress in H. pylori vaccines at the preclinical stage. Articles published from January 2018 to August 2022 were systematically searched using PubMed, Scopus, Web of Science, and Medline. After the screening process, 45 articles were eligible for inclusion in this review. Probiotics (n = 9 studies) and natural products from plants (n = 28 studies) were observed to inhibit the growth of H. pylori, improve immune response, reduce inflammation, and reduce the pathogenic effects of H. pylori virulence factors. Natural products from plants also showed anti-biofilm activity against H. pylori. However, clinical trials of natural products from plants and probiotics are still lacking. A paucity of data assessing the nanoparticle activity of N-acylhomoserine lactonase-stabilized silver against H. pylori was observed. Nonetheless, one nanoparticle study showed anti-biofilm activity against H. pylori. Promising results of H. pylori vaccine candidates (n = 7) were observed at preclinical stage, including elicitation of a humoral and mucosal immune response. Furthermore, the application of new vaccine technology including multi-epitope and vector-based vaccines using bacteria was investigated at the preclinical stage. Taken together, probiotics, natural products from plants, and nanoparticles exhibited antibacterial activity against H. pylori. New vaccine technology shows promising results against H. pylori.

Gastric microbiota in gastric cancer: Different roles of Helicobacter pylori and other microbes

Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide. The gastric microbiota plays a critical role in the development of GC. First, Helicobacter pylori (H. pylori) infection is considered a major risk factor for GC. However, recent studies based on microbiota sequencing technology have found that non-H. pylori microbes also exert effects on gastric carcinogenesis. Following the infection of H. pylori, gastric microbiota dysbiosis could be observed; the stomach is dominated by H. pylori and the abundances of non-H. pylori microbes reduce substantially. Additionally, decreased microbial diversity, alterations in the microbial community structure, negative interactions between H. pylori and other microbes, etc. occur, as well. With the progression of gastric lesions, the number of H. pylori decreases and the number of non-H. pylori microbes increases correspondingly. Notably, H. pylori and non-H. pylori microbes show different roles in different stages of gastric carcinogenesis. In the present mini-review, we provide an overview of the recent findings regarding the role of the gastric microbiota, including the H. pylori and non-H. pylori microbes, in the development of GC.

Dual therapy for Helicobacter pylori infection

ABSTRACT

Bismuth-containing quadruple therapy (BQT) has long been recommended for Helicobacter pylori ( H. pylori ) eradication in China. Meanwhile, in the latest national consensus in China, dual therapy (DT) comprising an acid suppressor and amoxicillin has also been recommended. In recent years, the eradication rate of H. pylori has reached >90% using DT, which has been used not only as a first-line treatment but also as a rescue treatment. Compared with BQT, DT has great potential for H. pylori eradication; however, it has some limitations. This review summarizes the development of DT and its application in H. pylori eradication. The H. pylori eradication rates of DT were comparable to or even higher than those of BQT or standard triple therapy, especially in the first-line treatment. The incidence of adverse events associated with DT was lower than that with other therapies. Furthermore, there were no significant differences in the effects of dual and quadruple therapies on gastrointestinal microecology. In the short term, H. pylori eradication causes certain fluctuations in the gastrointestinal microbiota; however, in the long term, the gastrointestinal microbiota eventually returns to its normal state. In the penicillin-naïve population, patients receiving DT have a high eradiation rate, better compliance, lower incidence of adverse reactions, and lower primary and secondary resistance to amoxicillin. These findings suggest the safety, efficacy, and potential of DT for H. pylori eradication.

Gastric microbiota dysbiosis and Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is one of the most common causes of gastric disease. The persistent increase in antibiotic resistance worldwide has made H. pylori eradication challenging for clinicians. The stomach is unsterile and characterized by a unique niche. Communication among microorganisms in the stomach results in diverse microbial fitness, population dynamics, and functional capacities, which may be positive, negative, or neutral. Here, we review gastric microecology, its imbalance, and gastric diseases. Moreover, we summarize the relationship between H. pylori and gastric microecology, including non-H. pylori bacteria, fungi, and viruses and the possibility of facilitating H. pylori eradication by gastric microecology modulation, including probiotics, prebiotics, postbiotics, synbiotics, and microbiota transplantation.

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

Introduction

Helicobacter pylori (Hp)-related dyspepsia has been related to gastroduodenal dysbiosis. The role of probiotic supplementation in the clinical management of Hp infection has been the object of several studies in terms of improvement of efficacy and tolerability of eradication treatments but data on their effects on the outcomes of post-eradication dyspepsia are lacking. The aim of the present study was to evaluate the influence of Lactobacillus rhamnosus GG (LGG) supplementation on bismuth quadruple therapy (BQT) in the clinical management of Hp-related infection both in terms of efficacy and tolerability and persistence of post-treatment dyspepsia.

Methods

A total of 164 (121 women) Hp-positive adult patients were enrolled in this pilot study and assigned to two different treatment regimens: group A received BQT for 10 days (three capsules qid, IPP bid) and group B received BQT for 10 days in combination with 6 × 109CFU LGG (ATCC53103) taken for 24 days (7 days before, 10 days during, and 7 days after therapy). Eradication was assessed after 45 days using the 13C-urea breath test (13C-UBT). Dyspepsia, distinguished into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS), was assessed at the time of enrollment and 6 months after eradication.

Results

Approximately 98 patients were enrolled in group A and 66 patients in group B. At the enrollment, dyspepsia was present in 76.5% of group A and 86.5% of group B. No significant differences were observed in eradication rate between the 2 groups, both in intention-to-treat (ITT) analysis (82.3 vs. 75.0%) and per-protocol (PP) analysis (95 vs. 96%), and in the presence of side effects during the treatment (70.6 vs. 65.4%). At 6 months after eradication of Hp infection, the persistence of dyspepsia was statistically higher in patients of group A than in group B (38.8 vs. 16.1%; p = 0.032). The positive influence of LGG supplementation in improving post-eradication dyspepsia resulted in statistically more effectiveness in PDS dyspepsia, whose remission was 41.7% in group A and 84% in group B patients (p = 0.011).

Conclusion

In conclusion, LGG supplementation during Hp eradication therapy, even if not affecting eradication rates and therapy-related side effects, significantly impacts the remission of dyspepsia.

Probiotics modulate gastrointestinal microbiota after Helicobacter pylori eradication: A multicenter randomized double-blind placebo-controlled trial

BACKGROUND

Helicobacter pylori (H. pylori) eradication has been reported to cause short-term disruption of gut microbiota. It is acknowledged that probiotics supplementation mitigates side effects induced by H. pylori eradication, yet its role on alleviating dysbiosis of microbiota is obscure.

OBJECTIVES

To evaluate the impact of probiotics on gastrointestinal microbiota after eradication therapy.

METHODS

This was a multicenter, double-blinded, randomized trial done at seven centers in China. A total of 276 treatment-naïve H. pylori-positive patients were randomly assigned to receive 14-day bismuth-containing quadruple therapy (esomeprazole, bismuth, amoxicillin, furazolidone) combined with probiotics (Bifidobacterium Tetragenous viable Bacteria Tablets) (n=140) or placebo (n=136) for 28 days. Saliva, gastric mucosa and fecal samples were collected before and after therapy for 16S rRNA gene sequencing.

RESULTS

The incidence of gastrointestinal adverse events was lower in probiotics group compared to placebo group (23.6% vs 37.7%, p=0.016), while there was no significant difference in eradication rate. We found dramatic perturbations of gut microbiota immediately following eradication, with the predominance of Proteobacteria in replacement of commensal Firmicutes and Bacteroidetes, and gradually restored after two weeks. The reduction of gut Bacteroidetes caused by eradication drugs was neutralized with probiotics supplementation. The gastric microbiota was completely reconstituted with H. pylori depleted and other taxa flourished. Of note, patients treated with probiotics showed smaller fluctuations of gastric microbiota compared to those with placebo. We also observed changes of saliva microbiota after H. pylori eradication, illustrated by the overgrowth of Neisseria and depletion of Streptococcus. The expansion of some pathogenic genera, including Porphyromonas, Leptotrichia, in the mouth was suppressed by probiotics.

CONCLUSION

This study not only demonstrated the beneficial effect of probiotics implementation on side events during H. pylori eradication but also provided a comprehensive profile of microbiome alterations along gastrointestinal tract that modulated by probiotics.

Refractory Helicobacter pylori infection and the gastric microbiota

Background

Curing refractory Helicobacter pylori infection is difficult. In addition, there is currently no research on the gastric microbiota of refractory H. pylori infection.

Methods

We designed a clinical retrospective study involving 32 subjects divided into three groups: 1. nAGHp.a, treatment-naïve patients with H. pylori infection; 2. nAGHp.b, H. pylori-negative patients; and 3. EFHp.a, patients with refractory H. pylori infection. Gastric mucosal samples from the biobank of our research center were collected for 16S rRNA sequencing analysis and bacterial functions were predicted via PICRUSt.

Results

There were significant differences between the H. pylori- positive group and the H. pylori-negative group in species diversity, gastric microbiota structure, and bacterial function. The beneficial Lactobacillus in the H. pylori-positive group were significantly enriched compared with those in the refractory H. pylori infection group. The bacterial interaction network diagram suggested that the microbiota interactions in the refractory H. pylori infection group decreased. The gastric microbiota of the refractory H. pylori infection group was enriched in the pathways of metabolism and infectious diseases (energy metabolism, bacterial secretion system, glutathione metabolism, protein folding and associated processing, sulphur metabolism, membrane and intracellular structural molecules, lipopolysaccharide biosynthesis, ubiquinone and other terpenoid-quinone biosynthesis, inorganic ion transport and metabolism, and metabolism of cofactors and vitamins) when compared with the H. pylori-positive group without treatment based on PICRUSt analysis.

Conclusion

Significant alterations occurred in the gastric microbiota when eradication of H. pylori failed multiple times. A history of eradication of multiple H. pylori infections leads to an imbalance in the gastric mucosal microbiota to a certain extent, which was mainly reflected in the inhibition of the growth of beneficial Lactobacillus in the stomach. Patients with refractory H. pylori infection may be at a higher risk of developing gastric cancer than other H. pylori-positive patients.

Bile reflux alters the profile of the gastric mucosa microbiota

BACKGROUND

Bile reflux can cause inflammation, gastric mucosa atrophy, and diseases such as stomach cancer. Alkaline bile flowing back into the stomach affects the intragastric environment and can alter the gastric bacterial community. We sought to identify the characteristics of the stomach mucosal microbiota in patients with bile reflux.

METHODS

Gastric mucosal samples were collected from 52 and 40 chronic gastritis patients with and without bile reflux, respectively. The bacterial profile was determined using 16S rRNA gene analysis.

RESULTS

In the absence of H. pylori infection, the richness (based on the Sobs and Chao1 indices; P <0.05) and diversity (based on Shannon indices; P <0.05) of gastric mucosa microbiota were higher in patients with bile reflux patients than in those without. There was a marked difference in the microbiota structure between patients with and without bile reflux (ANOSIM, R=0.058, P=0.011). While the genera, Comamonas, Halomonas, Bradymonas, Pseudomonas, Marinobacter, Arthrobacter, and Shewanella were enriched in patients with bile reflux, the genera, Haemophilus, Porphyromonas, and Subdoligranulum, were enriched in those without bile reflux.

CONCLUSION

Our results demonstrate that bile reflux significantly alters the composition of the gastric microbiota.

Effect of Probiotics on Host-Microbiota in Bacterial Infections

Diseases caused by bacteria cause millions of deaths every year. In addition, the problem of resistance to antibiotics is so serious that it threatens the achievements of modern medicine. This is a very important global problem as some bacteria can also develop persistence. Indeed, the persistence of pathogenic bacteria has evolved as a potent survival strategy to overcome host organisms’ defense mechanisms. Additionally, chronic or persistent infections may be caused by persisters which could facilitate antibiotic resistance. Probiotics are considered good bacteria. It has been described that the modulation of gut microbiota by probiotics could have a great potential to counteract the deleterious impact and/or regulate gut microbiota after bacterial infection. Probiotics might provide health benefits through the inhibition of pathogen growth or the replacement of pathogenic bacteria. Bearing in mind that current strategies to avoid bacterial persistence and prevent antibiotic resistance are not effective, other strategies need to be assessed. We have carried out a comprehensive review, which included the reported literature between 2016 and 2021, highlighting the clinical trials that reported the probiotics’ potential to regulate gut microbiota after bacterial infection and focusing in particular on the context of antibiotic resistance and persister cells.

Probiotics mitigate Helicobacter pylori-induced gastric inflammation and premalignant lesions in INS-GAS mice with the modulation of gastrointestinal microbiota

BACKGROUND

Dysbiosis of gastric microbiota including Helicobacter pylori (H. pylori) infection is associated with the development of stomach cancer. Probiotics have been shown to attenuate H. pylori-induced gastritis, although their role in cancer prevention remains unclear. Thus, we aimed to explore the effects of probiotics on H. pylori-induced carcinogenesis and the alterations of gastrointestinal microbiota.

METHODS

Male INS-GAS mice were randomly allocated to H. pylori-infected and non-infected groups. After 4 weeks, probiotic combination (containing Lactobacillus salivarius and Lactobacillus rhamnosus) was administered in drinking water for 12 weeks. Stomachs were collected for RNA-Sequencing and the differentially expressed genes were validated using RT profiler PCR array. 16S rRNA gene sequencing was performed to assess the alterations of gastrointestinal microbiota.

RESULTS

Probiotics significantly alleviate H. pylori-induced gastric pathology, including reduced infiltration of inflammation and lower incidence of precancerous lesions. RNA-Sequencing results showed that probiotics treatment decreased expressions of genes involved in pro-inflammatory pathways, such as NF-κB, IL-17, and TNF signaling pathway. Of note, probiotics did not suppress the growth of H. pylori, but dramatically reshaped the structure of both gastric and gut microbiota. The microbial diversity was increased in H. pylori-infected group after probiotics treatment. While gastric cancer-associated genera Lactobacillus and Staphylococcus were enriched in the stomach of H. pylori-infected group, the beneficial short-chain fatty acids-producing bacteria, including Bacteroides, Alloprevotella, and Oscellibacter, were more abundant in mice treated with probiotics. Additionally, probiotics restored the H. pylori-induced reduction of anti-inflammatory bacterium Faecalibaculum in the gut.

CONCLUSIONS

Probiotics therapy can protect against H. pylori-associated carcinogenesis probably through remodeling gastrointestinal microbiota, which in turn prevent host cells from malignant transformation.

Short-term and long-term alterations of gastrointestinal microbiota with different H. pylori eradication regimens: A meta-analysis

Background and Aims

The impacts of Helicobacter pylori (H. pylori) eradication on the gastrointestinal microbiota are controversial, and whether the short-term and long-term changes in the gastrointestinal microbiota following different eradication regimens are consistent remains inconclusive. This study aimed to examine the effects of various eradication regimens on the gastrointestinal microflora at follow-up evaluations within 7 days, at 1–3 months, and over 6 months changes in the gastrointestinal microbiota.

Materials and Methods

Studies reported on the PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrails.gov databases before March 2022 were collected. Data analysis and visualization were conducted using Review Manager 5.4.1. The tool of the Cochrane Collaboration to assess the risk of bias was suitable for randomized controlled trials with the Newcastle–Ottawa scale for nonrandomized controlled trials. In addition, the process was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

After a series of rigorous screenings, a total of 34 articles with 1,204 participants were included for this review analysis. The results showed changes in the gut microflora at the phylum level or the family and genus levels. After metronidazole-containing triple therapy, the number of Enterobacteriaceae increased at 1–3 months follow-up. After Metronidazole-free triple therapy, Actinobacteria decreased significantly, and this trend lasted for more than 6 months. Within 7 days after eradication treatment, the follow-up results showed a decrease in the number of Lactobacillus. After Bismuth-containing quadruple therapy, the changes in Actinobacteria fluctuated with the follow-up time. The changes in Proteobacteria showed a downward trend lasting for 1–3 months after eradication but returned to baseline levels over 6 months after eradication. Subgroup analyses indicated that host age could influence changes in the gut microbiota.

Conclusion

Different eradication regimens had varied effects on the short-term and long-term abundance of the gastrointestinal microbiota, but the decreasing trend of the microbiota diversity was the same for all regimens at the short-term follow-up. This study summarizes the changes of gut microbiota at different stages after different eradication regimens and hope to provide some references for supplementing probiotics, while further studies is needed to support these findings.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021292726

Saccharomyces boulardii Allows Partial Patients to Avoid Reusing Bismuth Quadruple for Helicobacter pylori Rescue Therapy: A Single-Center Randomized Controlled Study

Background

The increasing rate of drug resistance often leads to Helicobacter pylori (H. pylori) eradication failure and needs the rescue therapy. Thus, the exploration of new rescue therapeutic regimens is important. The present study was designed to test the beneficial effects of Saccharomyces boulardii (S.boulardii) prior to H. pylori rescue therapy basing on bismuth quadruple.

Methods

One hundred H. pylori-infected patients were randomly divided into two groups: study group and control group. Patients in the study group (n=50) underwent two-stages therapy: patients started with S.boulardii monotherapy for 2 weeks, and then tested for H. pylori infection after resting for 4 weeks without any therapy, patients who were still positive for H. pylori continued with bismuth quadruple eradication therapy. For the control group (n=50), all patients were observed and were not treated with any gastric drugs or antibiotics for 6 weeks, then those who were still positive for H. pylori received the same eradication therapy as the study group. Eradication rate, adverse events and the cost-effectiveness of two regimens were analyzed in this study.

Results

The H.pylori eradication rate of ITT (intent-to-treat) analysis and PP (per-protocol) analysis in the first phase of treatment were significantly higher in the study group than the control groups respectively (28.0% vs 2.0%, p<0.001 and 30.4% vs 2.1% p<0.001). For the total treatment effect, there were no significant differences in the eradication rate of ITT analysis (78.0% vs 80.0%) or PP analysis (90.7% vs 88.9%) between the study group and the control group. The cost‐effectiveness ratio of the study group was slightly higher than that of the control group (8.95 vs 8.55). There were two patients in the study group and four patients in the control group with the adverse events, respectively. There was no significant difference on the incidence of adverse events between the two groups (p=0.68).

Conclusion

S.boulardii may serve as a beneficial treatment option before H. pylori rescue therapy since it callowed partial patients to avoid reusing bismuth quadruple.

Metagenomic Changes of Gut Microbiota following Treatment of Helicobacter pylori Infection with a Simplified Low-Dose Quadruple Therapy with Bismuth or Lactobacillus reuteri

Background: Probiotic supplementation to antibiotic regimens against Helicobacter pylori infection has been proposed to improve eradication rate and to decrease detrimental effects on gut microbiota. Aims: To evaluate microbiota modifications due to a low-dose quadruple therapy with bismuth or Lactobacillus reuteri. Methods: Forty-six patients infected with H. pylori were prospectively enrolled in a single-centre, randomized controlled trial to receive b.i.d. with meals for 10 days low-dose quadruple therapy consisting of rabeprazole 20 mg and bismuth (two capsules of Pylera® plus 250 mg each of tetracycline and metronidazole), or the same dose of rabeprazole and antibiotics plus Gastrus® (L. reuteri), one tablet twice-a-day for 27 days. Stool samples were collected at the enrolment, at the end and 30–40 days after the treatment. Gut microbiota composition was investigated with 16S rRNA gene sequencing. Results: Eradication rate was by ITT 78% in both groups, and by PP analysis 85.7% and 95.5% for Gastrus® and bismuth group, respectively. Alpha and beta diversity decreased at the end of treatment and was associated with a reduction of bacterial genera beneficial for gut homeostasis, which was rescued 30–40 days later in both groups, suggesting a similar impact of the two regimens in challenging bacterial community complexity. Conclusions: Low-dose bismuth quadruple therapy proved to be effective with lower costs and amount of antibiotics and bismuth. Gastrus® might be an option for patients with contraindications to bismuth. L. reuteri was unable to significantly counteract dysbiosis induced by antibiotics. How to administer probiotics to prevent gut microbiota alterations remains an open question.

Role of Probiotics in the Management of Helicobacter pylori

The global prevalence of Helicobacter pylori (H. pylori) is estimated to be around 4.4 billion, with the majority of individuals affected in developing countries. Chronic infection of the gram-negative bacterium results in several gastrointestinal pathologies such as chronic gastritis, peptic ulcer, and cancer. Probiotics compete directly with H. pylori and help restore the gut microbial environment; these living microorganisms are comparatively more effective than the standard triple antibiotic regimen in the management of symptoms related to the pathogenic bacteria. The need for alternative therapy is better explained by the increasing rate of antibiotic resistance and the lowering of patient compliance to the standard treatment. Adjuvant administration of probiotics to H. pylori eradication therapy is associated with a higher H. pylori eradication rate, decreased diarrhea-related treatment, less common self-reported side effects, and higher treatment compliance. Therefore, with the ongoing and future resistance to antibiotics, this systematic review aims to investigate the use and efficacy of probiotics when used alone or in conjunction with the current guideline treatment.

A literature search was conducted using Pubmed, MEDLINE, and Cochrane for peer-reviewed articles published between January 1, 2016 and April 2022. MeSH terms used were: “H. pylori,” “H. pylori and probiotics,” “Probiotics,” “H. pylori treatment,” “Mechanism of Action” with subheadings as “clinical manifestations,” “treatment,” and “diagnosis.” All literature reviews, original papers, and case reports were included. This search strategy aimed to find literature that could describe the transmission and mechanism of action of H. pylori, the current treatment guidelines, and the efficacy of probiotics in eradicating H. pylori.

Gut Commensal Parabacteroides goldsteinii MTS01 Alters Gut Microbiota Composition and Reduces Cholesterol to Mitigate Helicobacter pylori-Induced Pathogenesis

Helicobacter pylori infection is closely associated with various gastrointestinal diseases and poses a serious threat to human health owing to its increasing antimicrobial resistance. H. pylori possesses two major virulence factors, vacuolating cytotoxin A (VacA) and cytotoxin-associated gene A (CagA), which are involved in its pathogenesis. Probiotics have recently been used to eradicate H. pylori infection and reduce the adverse effects of antibiotic-based therapies. Parabacteroides goldsteinii MTS01 is a novel next-generation probiotic (NGP) with activities that can alleviate specific diseases by altering the gut microbiota. However, the mechanism by which P. goldsteinii MTS01 exerts its probiotic effects against H. pylori infection remains unclear. Our results showed that administration of P. goldsteinii MTS01 to H. pylori-infected model mice altered the composition of the gut microbiota and significantly reduced serum cholesterol levels, which mitigated H. pylori-induced gastric inflammation. In addition, the pathogenic effects of H. pylori VacA and CagA on gastric epithelial cells were markedly abrogated by treatment with P. goldsteinii MTS01. These results indicate that P. goldsteinii MTS01 can modulate gut microbiota composition and has anti-virulence factor functions, and thus could be developed as a novel functional probiotic for reducing H. pylori-induced pathogenesis.

Effect of Helicobacter Pylori Eradication on Human Gastric Microbiota: A Systematic Review and Meta-Analysis

Background

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer and eradication of H. pylori is recommended as an effective gastric cancer prevention strategy. The infected individuals show microbial dysbiosis of gastric microbiota. In recent years, agrowing number of studies have focused on gastric microbiota changes following H. pylori eradication. In the present study, we aim to evaluate the influence of successful H. pylori eradication on the short-term and long-term alterations of human gastric microbiota using a method of systematic review and meta-analysis.

Methods

We did a systematic search based on three databases (PubMed, EMBASE, and Web of Science) in November 2021. Additional articles were also identified by reviewing references cited in the included papers. Human studies that reported changes in gastric microbiota following successful H. pylori eradication were enrolled. PROSPERO registration number: CRD42021293796.

Results

In total, nine studies enrolling 546 participants were included. Regarding quadruple therapy, alpha diversity indexes increased within 1 month after eradication; significant differences in gastric microbial community structure between before and after eradication were also seen within 1 month. The trends of the above-mentioned diversity changes persisted with a follow-up of 6 months. The microbial composition altered significantly after eradication and the relative abundance of H. pylori-related taxa decreased. Accordingly, gastric commonly dominant commensals were enriched. Bioinformatic analyses of microbiota functions showed that bacteria reproduction-related pathways were down-regulated and pathways of gastric acid secretion, etc. were up-regulated. For triple therapy, similar trends of alpha diversity and beta diversity changes were observed in the short-term and long-term follow-up. Also, after eradication, H. pylori was not the gastric dominant bacteria and similar changes in gastric microbial composition were found. For gastric microbial interactions, a decrease in microbial interactions was seen after eradication. Additionally, regarding whether successful H. pylori eradication could restore gastric microbiota to uninfected status, the results remain controversial.

Conclusion

In conclusion, successful H. pylori eradication could reverse the gastric microbiota dysbiosis and show beneficial effects on gastric microbiota. Our findings may provide new insight for exploring the role of H. pylori and the whole gastric microbiota in gastric carcinogenesis.

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

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.

The double-edged sword of probiotic supplementation on gut microbiota structure in Helicobacter pylori management

As Helicobacter pylori management has become more challenging and less efficient over the last decade, the interest in innovative interventions is growing by the day. Probiotic co-supplementation to antibiotic therapies is reported in several studies, presenting a moderate reduction in drug-related side effects and a promotion in positive treatment outcomes. However, the significance of gut microbiota involvement in the competence of probiotic co-supplementation is emphasized by a few researchers, indicating the alteration in the host gastrointestinal microbiota following probiotic and drug uptake. Due to the lack of long-term follow-up studies to determine the efficiency of probiotic intervention in H. pylori eradication, and the delicate interaction of the gut microbiota with the host wellness, this review aims to discuss the gut microbiota alteration by probiotic co-supplementation in H. pylori management to predict the comprehensive effectiveness of probiotic oral administration.Abbreviations: acyl-CoA- acyl-coenzyme A; AMP- antimicrobial peptide; AMPK- AMP-activated protein kinase; AP-1- activator protein 1; BA- bile acid; BAR- bile acid receptor; BCAA- branched-chain amino acid; C2- acetate; C3- propionate; C4- butyrate; C5- valeric acid; CagA- Cytotoxin-associated gene A; cAMP- cyclic adenosine monophosphate; CD- Crohn's disease; CDI- C. difficile infection; COX-2- cyclooxygenase-2; DC- dendritic cell; EMT- epithelial-mesenchymal transition; FMO- flavin monooxygenases; FXR- farnesoid X receptor; GPBAR1- G-protein-coupled bile acid receptor 1; GPR4- G protein-coupled receptor 4; H2O2- hydrogen peroxide; HCC- hepatocellular carcinoma; HSC- hepatic stellate cell; IBD- inflammatory bowel disease; IBS- irritable bowel syndrome; IFN-γ- interferon-gamma; IgA immunoglobulin A; IL- interleukin; iNOS- induced nitric oxide synthase; JAK1- janus kinase 1; JAM-A- junctional adhesion molecule A; LAB- lactic acid bacteria; LPS- lipopolysaccharide; MALT- mucosa-associated lymphoid tissue; MAMP- microbe-associated molecular pattern; MCP-1- monocyte chemoattractant protein-1; MDR- multiple drug resistance; mTOR- mammalian target of rapamycin; MUC- mucin; NAFLD- nonalcoholic fatty liver disease; NF-κB- nuclear factor kappa B; NK- natural killer; NLRP3- NLR family pyrin domain containing 3; NOC- N-nitroso compounds; NOD- nucleotide-binding oligomerization domain; PICRUSt- phylogenetic investigation of communities by reconstruction of unobserved states; PRR- pattern recognition receptor; RA- retinoic acid; RNS- reactive nitrogen species; ROS- reactive oxygen species; rRNA- ribosomal RNA; SCFA- short-chain fatty acids; SDR- single drug resistance; SIgA- secretory immunoglobulin A; STAT3- signal transducer and activator of transcription 3; T1D- type 1 diabetes; T2D- type 2 diabetes; Th17- T helper 17; TLR- toll-like receptor; TMAO- trimethylamine N-oxide; TML- trimethyllysine; TNF-α- tumor necrosis factor-alpha; Tr1- type 1 regulatory T cell; Treg- regulatory T cell; UC- ulcerative colitis; VacA- Vacuolating toxin A.