Review: Helicobacter pylori infection in children

Rapid diagnosis and precision treatment of Helicobacter pylori infection in clinical settings

Helicobacter pylori is a gram-negative bacterium that colonizes the stomach of approximately half of the worldwide population, with higher prevalence in densely populated areas like Asia, the Caribbean, Latin America, and Africa. H. pylori infections range from asymptomatic cases to potentially fatal diseases, including peptic ulcers, chronic gastritis, and stomach adenocarcinoma. The management of these conditions has become more difficult due to the rising prevalence of drug-resistant H. pylori infections, which ultimately lead to gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. In 1994, the International Agency for Research on Cancer (IARC) categorized H. pylori as a Group I carcinogen, contributing to approximately 780,000 cancer cases annually. Antibiotic resistance against drugs used to treat H. pylori infections ranges between 15% and 50% worldwide, with Asian countries having exceptionally high rates. This review systematically examines the impacts of H. pylori infection, the increasing prevalence of antibiotic resistance, and the urgent need for accurate diagnosis and precision treatment. The present status of precision treatment strategies and prospective approaches for eradicating infections caused by antibiotic-resistant H. pylori will also be evaluated.

Use of Deep-Amplicon Sequencing (DAS), Real-Time PCR and In Situ Hybridization to Detect H. pylori and Other Pathogenic Helicobacter Species in Feces from Children

BACKGROUND

Detecting Helicobacter pylori in fecal samples is easier and more comfortable than invasive techniques, especially in children. Thus, the objective of the present work was to detect H. pylori in feces from children by molecular methods as an alternative for diagnostic and epidemiological studies.

METHODS

Forty-five fecal samples were taken from pediatric patients who presented symptoms compatible with H. pylori infection. HpSA test, culture, real-time quantitative PCR (qPCR), fluorescence in situ hybridization (FISH), direct viable count associated with FISH (DVC-FISH), and Illumina-based deep-amplicon sequencing (DAS) were applied.

RESULTS

No H. pylori colonies were isolated from the samples. qPCR analysis detected H. pylori in the feces of 24.4% of the patients. In comparison, DVC-FISH analysis showed the presence of viable H. pylori cells in 53.3% of the samples, 37% of which carried 23S rRNA mutations that confer resistance to clarithromycin. After DAS, H. pylori-specific 16S rDNA sequences were detected in 26 samples. In addition, DNA from H. hepaticus was identified in 10 samples, and H. pullorum DNA was detected in one sample.

CONCLUSION

The results of this study show the presence of H. pylori, H. hepaticus, and H. pullorum in children's stools, demonstrating the coexistence of more than one Helicobacter species in the same patient. The DVC-FISH method showed the presence of viable, potentially infective H. pylori cells in a high percentage of the children's stools. These results support the idea that fecal-oral transmission is probably a common route for H. pylori and suggest possible fecal-oral transmission of other pathogenic Helicobacter species.

Helicobacter pylori antibiotic resistance profile in Chinese children with upper gastrointestinal symptoms and a literature review for developing personalized eradicating strategies

Background: H. pylori (Helicobacter pylori) infections typically occur in early childhood. Although the prevalence of H. pylori in children is lower than that in adults, the eradication rate of this infection in children is relatively low because of resistance. In this study, we analyzed personalized treatment strategies to achieve treatment goals based on H. pylori resistance characteristics. This retrospective single-center study was conducted between January 2019 and December 2022 and enrolled 1,587 children who presented with upper gastrointestinal symptoms and underwent endoscopy. H. pylori culturing and antimicrobial susceptibility testing were performed. Results: Culture-positive results for H. pylori were obtained in 535 children. The resistance rates to clarithromycin (CLA), metronidazole (MET), and levofloxacin (LEV) were 39.8%, 78.1%, and 20.2%, respectively. None of the isolates were resistant to tetracycline (TET), amoxicillin (AMO), or furazolidone (FZD). Double resistance rates to CLA + MET, CLA + LEV, and MET + LEV were 19.1%, 3.0%, and 5.8%, respectively. Notably, triple-resistant to CLA + MET + LEV was 9.7%. Based on susceptibility tests, individualized triple therapy [proton pump inhibitor (PPI) +AMO + CLA/MET] was selected for 380 children with H. pylori sensitive to MET and/or CLA. In 155 children resistant to CLA and MET, bismuth-based quadruple therapy was recommended; for unable to receive bismuth, concomitant therapy was recommended for 14 children (<8 years of age); triple therapy with TET was recommended for 141 children (>8 years of age), with 43 children (>14 years of age) requiring FZD rather than TET. Conclusion: Resistance to H. pylori in Chinese children was relatively poor. Personalized therapy regimens should be based on susceptibility tests and avoided factors associated with treatment failure.

Advances in Helicobacter pylori vaccine research: From candidate antigens to adjuvants-A review

BACKGROUND

Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects approximately 50% of the world's population and has been strongly associated with chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoma, and gastric cancer. The elimination of H. pylori is currently considered one of the most effective strategies for the treatment of gastric-related diseases, so antibiotic therapy is the most commonly used regimen for the treatment of H. pylori infection. Although this therapy has some positive effects, antibiotic resistance has become another clinically prominent problem. Therefore, the development of a safe and efficient vaccine has become an important measure to prevent H. pylori infection.

METHODS

PubMed and ClinicalTrials.gov were systematically searched from January 1980 to March 2023 with search terms-H. pylori vaccine, adjuvants, immunization, pathogenesis, and H. pylori eradication in the title and/or abstract of literature. A total of 5182 documents were obtained. Based on the principles of academic reliability, authority, nearly publicated, and excluded the similar documents, finally, 75 documents were selected, organized, and analyzed.

RESULTS

Most of the candidate antigens used as H. pylori vaccines in these literatures are whole-cell antigens and virulence antigens such as UreB, VacA, CagA, and HspA, and the main types of vaccines for H. pylori are whole bacteria vaccines, vector vaccines, subunit vaccines, nucleic acid vaccines, epitope vaccines, etc. Some vaccines have shown good immune protection in animal trials; however, few vaccines show good in clinical trials. The only H. pylori vaccine passed phase 3 clinical trial is a recombinant subunit vaccine using Urease subunit B (UreB) as the vaccine antigen, and it shows good prophylactic effects. Meanwhile, the adjuvant system for vaccines against this bacterium has been developed considerably. In addition to the traditional mucosal adjuvants such as cholera toxin (CT) and E. coli heat labile enterotoxin (LT), there are also promising safer and more effective mucosal adjuvants. All these advances made safe and effective H. pylori vaccines come into service as early as possible.

CONCLUSIONS

This review briefly summarized the advances of H. pylori vaccines from two aspects, candidates of antigens and adjuvants, to provide references for the development of vaccine against this bacterium. We also present our prospects of exosomal vaccines in H. pylori vaccine research, in the hope of inspiring future researchers.

Helicobacter pylori infection attenuates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in C57/BL6 mice

BACKGROUND

Although numerous studies have suggested a negative correlation between Helicobacter pylori (H. pylori) infection and allergies, there has been limited research on the relationship between H. pylori infections and atopic dermatitis (AD). The present study aimed to investigate the effects of H. pylori infection in an AD mouse model and identify potential mechanisms related to type 2 immunity, skin barrier defects, and pruritus.

METHODS

A model of AD-like symptoms was established with 2,4-dinitrochlorobenzene (DNCB) after infection of the gastric cavity with H. pylori. Analysis of the expression of key inflammatory cytokines and serum levels of immunoglobulin E (IgE) was based on enzyme-linked immunosorbent assay (ELISA). The expression of filaggrin (FLG) and loricrin (LOR) were analyzed by immunohistochemistry staining. The evaluation of STAT1, STAT3, phosphorylated STAT1 (phospho-STAT1), and phosphorylated STAT3 (phospho-STAT1) expression levels in skin lesions was performed using western blot.

RESULTS

The present study showed that the H. pylori-positive AD group (HP+AD+) exhibited milder skin lesions, including erythema, erosion, swelling, and scaling, than the H. pylori-negative AD group (HP-AD+). Additionally, HP+AD+ displayed lower levels of IgE in serum, and downregulated expression of interleukins 4 and 31 (IL-4 and IL-31) in serum. Furthermore, HP+AD+ demonstrated higher expression of filaggrin and loricrin than HP-AD+. Notably, H. pylori significantly reduced the amount of phosphorylated STAT1 and STAT3.

CONCLUSION

Helicobacter pylori infection negatively regulates the inflammatory response by affecting inflammatory factors in the immune response, and repairs the defective epidermal barrier function. In addition, H. pylori infection may reduce IL-31, thereby alleviating pruritus. These effects may be associated with the inhibition of JAK-STAT signaling activation.

Helicobacter pylori Infections in Children

In the context of epidemiology, host response, disease presentation, diagnosis, and treatment management, the manifestation of Helicobacter pylori (H. pylori) infection diverges between children and adults. H. pylori infection stands out as one of the most prevalent bacterial infections globally, and its prevalence in both children and adults is decreasing in many developing countries but some still struggle with a high prevalence of pediatric H. pylori infection and its consequences. The majority of infected children are asymptomatic and pediatric studies do not support the involvement of H. pylori in functional disorders such as recurrent abdominal pain. The pathophysiology of H. pylori infection relies on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors. This interaction gives rise to diverse gastritis phenotypes, which subsequently influence the potential development of various gastroduodenal pathologies. In clinical settings, the diagnosis of this infection in childhood requires an upper gastrointestinal endoscopic exam with mucosal biopsy samples for histology and culture, or Polymerase Chain Reaction (PCR) at the very least. When warranted, eradication treatment should be given when good compliance is expected, and there should be systematic use of a treatment adapted to the antimicrobial susceptibility profile. To combat the burgeoning threat of multidrug resistance, vigilant surveillance of resistance patterns and strategic antibiotic management are paramount.

Management of Helicobacter pylori infection in paediatric patients in Europe: results from the EuroPedHp Registry

Purpose

The EuroPedHp-registry aims to monitor guideline-conform management, antibiotic resistance, and eradication success of 2-week triple therapy tailored to antibiotic susceptibility (TTT) in Helicobacter pylori-infected children.

Methods

From 2017 to 2020, 30 centres from 17 European countries reported anonymized demographic, clinical, antibiotic susceptibility, treatment, and follow-up data. Multivariable logistic regression identified factors associated with treatment failure.

Results

Of 1605 patients, 873 had follow-up data (53.2% female, median age 13.0 years, 7.5% with ulcer), thereof 741 (85%) treatment naïve (group A) and 132 (15%) after failed therapy (group B). Resistance to metronidazole was present in 21% (A: 17.7%, B: 40.2%), clarithromycin in 28.8% (A: 25%, B: 51.4%), and both in 7.1% (A: 3.8%, B: 26.5%). The majority received 2-week tailored triple therapy combining proton pump inhibitor (PPI), amoxicillin with clarithromycin (PAC) or metronidazole (PAM). Dosing was lower than recommended for PPI (A: 49%, B: 41%) and amoxicillin (A: 6%, B: 56%). In treatment naïve patients, eradication reached 90% (n = 503, 95% CI 87–93%) and 93% in compliant children (n = 447, 95% CI 90–95%). Tailored triple therapy cured 59% patients after failed therapy (n = 69, 95% CI 48–71%). Treatment failure was associated with PAM in single clarithromycin resistance (OR = 2.47, 95% CI 1.10–5.53), with PAC in single metronidazole resistance (OR = 3.44, 95% CI 1.47–8.08), and with low compliance (OR = 5.89, 95% CI 2.49–13.95).

Conclusions

Guideline-conform 2-weeks therapy with PPI, amoxicillin, clarithromycin or metronidazole tailored to antibiotic susceptibility achieves primary eradication of ≥ 90%. Higher failure rates in single-resistant strains despite tailored treatment indicate missed resistance by sampling error.

Gastric mucosal precancerous lesions in Helicobacter pylori-infected pediatric patients in central China: A single-center, retrospective investigation

BACKGROUND

Helicobacter pylori (H. pylori) infects about 50% of the world population and is the major cause of chronic gastritis, peptic ulcers, and gastric cancer. Chronic H. pylori infection induces gastric mucosal precancerous lesions mostly in adulthood, and it is debatable whether these pathological conditions can occur in childhood and adolescents as well. Since this is a critical issue to determine if intervention should be offered for this population group, we investigated the gastric mucosal precancerous lesions in pediatric patients in an area in central China with a high prevalence of H. pylori and gastric cancer.

AIM

To investigate the relationship of H. pylori infection and gastric mucosal precancerous lesions in children and adolescents in central China.

METHODS

We screened 4258 ward-admitted children and adolescent patients with upper gastrointestinal symptoms, and finally enrolled 1015 pediatric patients with H. pylori infection and endoscopic and histological data. H. pylori infection status was determined by rapid urease test and histopathological examination. Both clinical and pathological data were collected and analyzed retrospectively. Occurrence of gastric mucosal precancerous lesions, inflammatory activity and degree of inflammatory cell infiltration between H. pylori-positive and -negative groups were compared.

RESULTS

Among the 1015 eligible children and adolescents, the overall H. pylori infection rate was 84.14% (854/1015). The infection rate increased with age. The incidence of gastric mucosal precancerous lesions in H. pylori-infected children was 4.33% (37/854), which included atrophic gastritis (17 cases), intestinal metaplasia (11 cases) and dysplasia (9 cases). In H. pylori-negative patients, only 1 atrophic gastritis case [0.62%, (1/161)] was found (P < 0.05). Active inflammation in H. pylori-infected patients was significantly higher than that in non-infected patients, and the H. pylori-infected group showed more severe lymphocyte and neutrophil granulocyte infiltration (P < 0.001). In addition, endoscopy revealed that the most common findings in H. pylori-positive patients were antral nodularity, but in H. pylori-negative patients only superficial gastritis was observed.

CONCLUSION

In children and adolescents, gastric mucosal precancerous lesions occurred in 4.33% of H. pylori-infected patients in central China. These cases included atrophic gastritis, intestinal metaplasia, and dysplasia. The data revealed an obvious critical issue requiring future investigation and intervention for this population group.

Nanomechanical Hallmarks of Helicobacter pylori Infection in Pediatric Patients

Background: the molecular mechanism of gastric cancer development related to Helicobacter pylori (H. pylori) infection has not been fully understood, and further studies are still needed. Information regarding nanomechanical aspects of pathophysiological events that occur during H. pylori infection can be crucial in the development of new prevention, treatment, and diagnostic measures against clinical consequences associated with H. pylori infection, including gastric ulcer, duodenal ulcer, and gastric cancer. Methods: in this study, we assessed mechanical properties of children’s healthy and H. pylori positive stomach tissues and the mechanical response of human gastric cells exposed to heat-treated H. pylori cells using atomic force microscopy (AFM NanoWizard 4 BioScience JPK Instruments Bruker). Elastic modulus (i.e., the Young’s modulus) was derived from the Hertz–Sneddon model applied to force-indentation curves. Human tissue samples were evaluated using rapid urease tests to identify H. pylori positive samples, and the presence of H. pylori cells in those samples was confirmed using immunohistopathological staining. Results and conclusion: collected data suggest that nanomechanical properties of infected tissue might be considered as markers indicated H. pylori presence since infected tissues are softer than uninfected ones. At the cellular level, this mechanical response is at least partially mediated by cell cytoskeleton remodeling indicating that gastric cells are able to tune their mechanical properties when subjected to the presence of H. pylori products. Persistent fluctuations of tissue mechanical properties in response to H. pylori infection might, in the long-term, promote induction of cancer development.