Animal Model Reveals Potential Waterborne Transmission of Helicobacter pylori Infection

Epidemiology, Diagnosis and Risk Factors of Helicobacter pylori Infection

Helicobacter pylori is a human-specific pathogen, which leads to gastric pathologies including gastric cancer. It is a highly unique bacterium considered as a carcinogenic agent. H. pylori remains a major human health problem, responsible for ~90% of the gastric cancer cases. Approximately four billion individuals have been detected for H. pylori infection worldwide in 2015. At the turn of the twenty-first century, the prevalence of H. pylori has been declining in highly industrialized countries of the Western world, whereas prevalence has plateaued at a high level in developing and newly industrialized countries. However, the infection status remains high in immigrants coming from countries with high prevalence of H. pylori infection. H. pylori can be diagnosed both by invasive and non-invasive methods. Urea breath test and stool antigens detection are among the most commonly used non-invasive ones. Although the way H. pylori is transmitted remains still not fully clear, the level of contamination is strongly dependent on the familial and environmental context, with a drastic impact of living conditions with poor hygiene and sanitation. However, familial socioeconomic status is the main risk factor for H. pylori infection among children. In addition, food and water source have a high impact on the prevalence of H. pylori infection worldwide. This chapter highlights the latest knowledge in the epidemiology of H. pylori infection, its diagnosis and critical risk factors responsible for its high prevalence in some populations and geographic areas.

Correlation among fecal indicator bacteria and physicochemical parameters with the presence of Helicobacter pylori DNA in raw and drinking water from Bogotá, Colombia

BACKGROUND

The quality of raw and drinking water is a matter of considerable concern due to the possibility of fecal contamination. To assess the quality and public health risk of different types of water, the fecal indicator bacteria (FIB) are used. However, some pathogens, such as Helicobacter pylori, may be present in water when FIB cannot be found. H pylori is recognized as the causative agent of chronic gastritis, peptic and duodenal ulcers, and gastric cancer. The aim of this study was to evaluate the relationships among physicochemical parameters, FIB concentrations, and the presence of H pylori DNA in raw and drinking water from Bogotá, Colombia.

MATERIALS AND METHODS

A total of 310 water samples were collected 1 day per week from July 2015 to August 2016, and physicochemical parameters (pH, turbidity, conductivity, and residual free chlorine) were measured. Presence of H pylori DNA was determined and quantified by quantitative polymerase chain reaction (qPCR). Fecal indicator bacteria (total coliforms, Escherichia coli, and spores of sulfite-reducing Clostridia) were enumerated by using standard culture techniques.

RESULTS

Thirty of 155 (31%) raw water samples and forty-eight of 155 (38.7%) drinking water samples were positive for the presence of H pylori. No statistically significant relationships were found between physicochemical parameters or FIB with the presence or absence of H pylori in any sample (P < 0.05).

CONCLUSIONS

This study provides evidence of the presence of H pylori DNA in raw and drinking water in Bogotá, and shows that the detection and enumeration of FIB and physicochemical parameters in water do not correlate with the risk of contamination with H pylori.

Immunization with a Synthetic Helicobacter pylori Peptide Induces Secretory IgA Antibodies and Protects Mice against Infection

Helicobacter pylori is a spiral Gram-negative bacterium associated with inflammation of the gastric mucosa, peptic ulcer, and gastric adenocarcinoma, whose treatment has failed due to antibiotic resistance and side effects. Furthermore, because there are no vaccines effective against H. pylori, an appropriate vaccine design targeting conserved/essential genes must be identified. In the present study, a H. pylori 50-52 kDa immunogen-derived peptide antigen with the sequence Met-Val-Thr-Leu-Ile-Asn-Asn-Glu (MVTLINNE) was used to immunize against H. pylori infection. For this, mice received an intraperitoneal injection of 100 μg of H. pylori peptide on the first week, followed by two weekly subcutaneous reinforcements and further 109 bacteria administration in the drinking water for 3 weeks. Thymic cells proliferative responses to concanavalin A, serum levels of IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ, and TNF-α cytokines, and IgG1, IgG2a, IgG2b, IgG3 IgM, and IgA immunoglobulins were evaluated. Significant (p < 0.05) increases on lymphoproliferation and spleen weights after immunization were observed. In contrast, infection significantly (p < 0.05) decreased lymphoproliferation, which was recovered in immunized mice. In addition, levels of serum TH1 and TH2 cytokines were not altered after immunization, except for the significant increase in IL-6 production in immunized and/or infected animals. Moreover, immunization correlated with plasma secretory IgA and IgG, whereas infection alone only elicited IgM antibodies. Peptide immunization protected 100% of mice against virulent H. pylori. MVTLINNE peptide deserves further research as an approach to the prophylaxis of H. pylori infection.

Prevalence and Risk Factors of Helicobacter pylori Infection among Children Aged 1 to 15 Years at Holy Innocents Children's Hospital, Mbarara, South Western Uganda

Background

Helicobacter pylori infection affects more than half of the world's population. The infection is generally acquired during childhood but can remain asymptomatic, with long-term clinical sequelae including gastritis, peptic ulcer disease, and stomach cancer.

Methods

The study was approved by Institutional Review Committee of Mbarara University of Science and Technology. After obtaining informed consent from parents/legal guardians, illegible children who presented with gastrointestinal complaints at Holy Innocents Children's Hospital were recruited; structured questionnaires were administered to the parents/guardians to collect information on sociodemographic data and risk factors of H. pylori infection. Four (4) millilitres of blood was collected from each child and tested for H. pylori blood Antibody test and stool specimens were used for H. pylori antigen test.

Results

The prevalence of H. pylori infection among the study participants was 24.3%. The infection rate increased with increase in age of the participants, from 16.2% among 1to 5 years old to 27.2% among 6 to 10 years. Infections were higher among school going children (68/74, p=0.003, OR 3.9; CI: 1.5 to 10.6) and children from crowded households (59/74, p<0.001, OR 2.6, and CI 1.3 to 5.0), unsafe source of drinking water at schools (46/74, p=0.003), and lack of sanitary facility at homes (57/74, p=0.001, and OR 1.6 CI 0.7 to 3.6).

Conclusion

The prevalence of H. pylori infection among children aged 1 to 15 years at Holy Innocents Children's Hospital was high and increases with age. School attendance, lack of sanitary facility, lack of safe drinking water, and overcrowding were the risk factors associated with H. pylori infection.

An assessment of drinking water contamination with Helicobacter pylori in Lima, Peru

BACKGROUND

Helicobacter pylori is a gut bacterium that is the primary cause of gastric cancer. H. pylori infection has been consistently associated with lack of access to sanitation and clean drinking water. In this study, we conducted time-series sampling of drinking water in Lima, Peru, to examine trends of H. pylori contamination and other water characteristics.

MATERIALS AND METHODS

Drinking water samples were collected from a single faucet in Lima's Lince district 5 days per week from June 2015 to May 2016, and pH, temperature, free available chlorine, and conductivity were measured. Quantities of H. pylori in all water samples were measured using quantitative polymerase chain reaction. Relationships between the presence/absence and quantity of H. pylori and water characteristics in the 2015-2016 period were examined using regression methods accounting for the time-series design.

RESULTS

Forty-nine of 241 (20.3%) of drinking water samples were contaminated with H. pylori. Statistical analyses identified no associations between sampling date and the likelihood of contamination with H. pylori. Statistically significant relationships were found between lower temperatures and a lower likelihood of the presence of H. pylori (P < .05), as well as between higher pH and higher quantities of H. pylori (P < .05).

CONCLUSIONS

This study has provided evidence of the presence of H. pylori DNA in the drinking water of a single drinking water faucet in the Lince district of Lima. However, no seasonal trends were observed. Further studies are needed to determine the presence of H. pylori in other drinking water sources in other districts in Lima, as well as to determine the viability of H. pylori in these water sources. Such studies would potentially allow for better understanding and estimates of the risk of infection due to exposure to H. pylori in drinking water.

Reduced infectivity of waterborne viable but nonculturable Helicobacter pylori strain SS1 in mice

BACKGROUND

Helicobacter pylori infection has been consistently associated with lack of access to clean water and proper sanitation, but no studies have demonstrated that the transmission of viable but nonculturable (VBNC) H. pylori can occur from drinking contaminated water. In this study, we used a laboratory mouse model to test whether waterborne VBNCH. pylori could cause gastric infection.

MATERIALS AND METHODS

We performed five mouse experiments to assess the infectivity of VBNCH. pylori in various exposure scenarios. VBNC viability was examined using Live/Dead staining and Biolog phenotype metabolism arrays. High doses of VBNCH. pylori in water were chosen to test the "worst-case" scenario for different periods of time. One experiment also investigated the infectious capabilities of VBNC SS1 using gavage. Further, immunocompromised mice were exposed to examine infectivity among potentially vulnerable groups. After exposure, mice were euthanized and their stomachs were examined for H. pylori infection using culture and PCR methodology.

RESULTS

VBNC cells were membrane intact and retained metabolic activity. Mice exposed to VBNCH. pylori via drinking water and gavage were not infected, despite the various exposure scenarios (immunocompromised, high doses) that might have permitted infection with VBNCH. pylori. The positive controls exposed to viable, culturable H. pylori did become infected.

CONCLUSIONS

While other studies that have used viable, culturable SS1 via gavage or drinking water exposures to successfully infect mice, in our study, waterborne VBNC SS1 failed to colonize mice under all test conditions. Future studies could examine different H. pylori strains in similar exposure scenarios to compare the relative infectivity of the VBNC vs the viable, culturable state, which would help inform future risk assessments of H. pylori in water.

Antibiotic resistance among Helicobacter pylori clinical isolates in Lima, Peru

Objectives

Gastric carcinoma is the most common cancer and cause of cancer mortality in Peru. Helicobacter pylori, a bacterium that colonizes the human stomach, is a Group 1 carcinogen due to its causal relationship to gastric carcinoma. While eradication of H. pylori can help prevent gastric cancer, characterizing regional antibiotic resistance patterns is necessary to determine targeted treatment for each region. Thus, we examined primary antibiotic resistance in clinical isolates of H. pylori in Lima, Peru.

Materials and methods

H. pylori strains were isolated from gastric biopsies of patients with histologically proven H. pylori infection. Primary antibiotic resistance among isolates was examined using E-test strips. Isolates were examined for the presence of the cagA pathogenicity island and the vacA m1/m2 alleles via polymerase chain reaction.

Results

Seventy-six isolates were recovered from gastric biopsies. Clinical isolates showed evidence of antibiotic resistance to 1 (27.6%, n=21/76), 2 (28.9%, n=22/76), or ≥3 antibiotics (40.8%). Of 76 isolates, eight (10.5%) were resistant to amoxicillin and clarithromycin, which are part of the standard triple therapy for H. pylori infection. No trends were seen between the presence of cagA, vacA m1, or vacA m2 and antibiotic resistance.

Conclusion

The rate of antibiotic resistance among H. pylori isolates in Lima, Peru, is higher than expected and presents cause for concern. To develop more targeted eradication therapies for H. pylori in Peru, more research is needed to better characterize antibiotic resistance among a larger number of clinical isolates prospectively.

The All-Age Prevalence of Helicobacter pylori Infection and Potential Transmission Routes. A Population-Based Study

BACKGROUND AND AIMS

Previous research on H. pylori epidemiology has mostly focused on adult populations. We have aimed to study H. pylori prevalence in all age groups including children and adolescents and to identify potential routes of transmission.

METHODS

Subjects from all age groups (children 0-11 years, adolescents 12-17 years and adults ≥18 years of age), recruited from both an urban and a rural community in Northern Norway, were invited to provide stool samples for the diagnosis of H. pylori antigen and to fill in a questionnaire (adult and adolescents only) on gastrointestinal symptoms, lifestyle factors and biometric data.

RESULTS

A total of 1 624 (35.3%) of the invited subjects, including 173 (39.3%) of the children, 46 (19.2%) of the adolescents, and 1 416 (36.1%) of the adults, responded to the invitation. H. pylori infection was nearly undetectable (0.6%) among the children, whereas the prevalence increased from 20% in adolescents toward a peak of 45% in the highest age group. Univariate analyses of possible risk factors of H. pylori infection showed significant associations to private well water, the use of outhouse toilet, and having farm animals in childhood, but the associations waned in multivariate analyses.

CONCLUSIONS

In our populations, with apparent high hygienic standards, the transmission of H. pylori infection may start not only in childhood, but also in adolescence, where potential transmission routes may be outdoor toilet use, private well water, and farm animals.

Vacuolating cytotoxin A (VacA) - A multi-talented pore-forming toxin from Helicobacter pylori

Helicobacter pylori is associated with severe and chronic diseases of the stomach and duodenum such as peptic ulcer, non-cardial adenocarcinoma and gastric lymphoma, making Helicobacter pylori the only bacterial pathogen which is known to cause cancer. The worldwide rate of incidence for these diseases is extremely high and it is estimated that about half of the world's population is infected with H. pylori. Among the bacterial virulence factors is the vacuolating cytotoxin A (VacA), which represents an important determinant of pathogenicity. Intensive characterization of VacA over the past years has provided insight into an ample variety of mechanisms contributing to host-pathogen interactions. The toxin is considered as an important target for ongoing research for several reasons: i) VacA displays unique features and structural properties and its mechanism of action is unrelated to any other known bacterial toxin; ii) the toxin is involved in disease progress and colonization by H. pylori of the stomach; iii) VacA is a potential and promising candidate for the inclusion as antigen in a vaccine directed against H. pylori and iv) the vacA gene is characterized by a high allelic diversity, and allelic variants contribute differently to the pathogenicity of H. pylori. Despite the accumulation of substantial data related to VacA over the past years, several aspects of VacA-related activity have been characterized only to a limited extent. The biologically most significant effect of VacA activity on host cells is the formation of membrane pores and the induction of vacuole formation. This review discusses recent findings and advances on structure-function relations of the H. pylori VacA toxin, in particular with a view to membrane channel formation, oligomerization, receptor binding and apoptosis.

Advances in nutritional therapy in inflammatory bowel diseases: Review

Inflammatory bowel diseases (IBD), including ulcerative colitis and Crohn's disease are chronic, life-long, and relapsing diseases of the gastrointestinal tract. Currently, there are no complete cure possibilities, but combined pharmacological and nutritional therapy may induce remission of the disease. Malnutrition and specific nutritional deficiencies are frequent among IBD patients, so the majority of them need nutritional treatment, which not only improves the state of nutrition of the patients but has strong anti-inflammatory activity as well. Moreover, some nutrients, from early stages of life are suspected as triggering factors in the etiopathogenesis of IBD. Both parenteral and enteral nutrition is used in IBD therapy, but their practical utility in different populations and in different countries is not clearly established, and there are sometimes conflicting theories concerning the role of nutrition in IBD. This review presents the actual data from research studies on the influence of nutrition on the etiopathogenesis of IBD and the latest findings regarding its mechanisms of action. The use of both parenteral and enteral nutrition as therapeutic methods in induction and maintenance therapy in IBD treatment is also extensively discussed. Comparison of the latest research data, scientific theories concerning the role of nutrition in IBD, and different opinions about them are also presented and discussed. Additionally, some potential future perspectives for nutritional therapy are highlighted.