Associations between Helicobacter pylori infection, co-morbid infections, gastrointestinal symptoms, and circulating cytokines in African children

Helicobacter pylori infection in infant rhesus macaque monkeys is associated with an altered lung and oral microbiome

It is estimated that more than half of the world population has been infected with Helicobacter pylori. Most newly acquired H. pylori infections occur in children before 10 years of age. We hypothesized that early life H. pylori infection could influence the composition of the microbiome at mucosal sites distant to the stomach. To test this hypothesis, we utilized the infant rhesus macaque monkey as an animal model of natural H. pylori colonization to determine the impact of infection on the lung and oral microbiome during a window of postnatal development. From a cohort of 4-7 month-old monkeys, gastric biopsy cultures identified 44% of animals infected by H. pylori. 16S ribosomal RNA gene sequencing of lung washes and buccal swabs from animals showed distinct profiles for the lung and oral microbiome, independent of H. pylori infection. In order of relative abundance, the lung microbiome was dominated by the phyla Proteobacteria, Firmicutes, Bacteroidota, Fusobacteriota, Campilobacterota and Actinobacteriota while the oral microbiome was dominated by Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota. In comparison to the oral cavity, the lung was composed of more genera and species that significantly differed by H. pylori status, with a total of 6 genera and species that were increased in H. pylori negative infant monkey lungs. Lung, but not plasma IL-8 concentration was also associated with gastric H. pylori load and lung microbial composition. We found the infant rhesus macaque monkey lung harbors a microbiome signature that is distinct from that of the oral cavity during postnatal development. Gastric H. pylori colonization and IL-8 protein were linked to the composition of microbial communities in the lung and oral cavity. Collectively, these findings provide insight into how H. pylori infection might contribute to the gut-lung axis during early childhood and modulate future respiratory health.

Advances in the study of the interaction between schistosome infections and the host's intestinal microorganisms

Schistosomiasis, also called bilharziasis, is a neglected tropical disease induced by schistosomes that infects hundreds of millions of people worldwide. In the life cycle of schistosomiasis, eggs are regarded as the main pathogenic factor, causing granuloma formation in the tissues and organs of hosts, which can cause severe gastrointestinal and liver granulomatous immune responses and irreversible fibrosis. Increasing evidence suggests that the gut microbiome influences the progression of schistosomiasis and plays a central role in liver disease via the gut-liver axis. When used as pharmaceutical supplements or adjunctive therapy, probiotics have shown promising results in preventing, mitigating, and even treating schistosomiasis. This review elucidates the potential mechanisms of this three-way parasite-host-microbiome interaction by summarizing schistosome-mediated intestinal flora disorders, local immune changes, and host metabolic changes, and elaborates the important role of the gut microbiome in liver disease after schistosome infection through the gut-liver axis. Understanding the mechanisms behind this interaction may aid in the discovery of probiotics as novel therapeutic targets and sustainable control strategies for schistosomiasis.

Helicobacter pylori Infection in Infant Rhesus Macaque Monkeys is Associated with an Altered Lung and Oral Microbiome

Background

It is estimated that more than half of the world population has been infected with Helicobacter pylori. Most newly acquired H. pylori infections occur in children before 10 years of age. We hypothesized that early life H. pylori infection could influence the composition of the microbiome at mucosal sites distant to the stomach. To test this hypothesis, we utilized the infant rhesus macaque monkey as an animal model of natural H. pylori colonization to determine the impact of infection on the lung and oral microbiome during a window of postnatal development.

Results

From a cohort of 4-7-month-old monkeys, gastric biopsy cultures identified 44% of animals infected by H. pylori. 16S ribosomal RNA gene sequencing of lung washes and buccal swabs from animals showed distinct profiles for the lung and oral microbiome, independent of H. pylori infection. In relative order of abundance, the lung microbiome was dominated by the phyla Proteobacteria, Firmicutes, Bacteroidota, Fusobacteriota, Campilobacterota and Actinobacteriota while the oral microbiome was dominated by Proteobacteria, Firmicutes, Bacteroidota, and Fusobacteriota. Relative to the oral cavity, the lung was composed of more genera and species that significantly differed by H. pylori status, with a total of 6 genera and species that were increased in H. pylori negative infant monkey lungs. Lung, but not plasma IL-8 concentration was also associated with gastric H. pylori load and lung microbial composition.

Conclusions

We found the infant rhesus macaque monkey lung harbors a microbiome signature that is distinct from that of the oral cavity during postnatal development. Gastric H. pylori colonization and IL-8 protein were linked to the composition of microbial communities in the lung and oral cavity. Collectively, these findings provide insight into how H. pylori infection might contribute to the gut-lung axis during early childhood and modulate future respiratory health.

The impact of Helicobacter pylori and intestinal helminth infections on gastric adenocarcinoma and inflammatory bowel disease in Sub-Saharan Africa

Gastric adenocarcinoma (GCA) is the 5th leading cancer globally with an estimated 1.1 million cases reported in 2020. Ninety percent of non-cardia GCAs are attributable to Helicobacter pylori (H. pylori), the most prevalent bacterial infection globally. Rates of H. pylori infection are highest in Sub-Saharan Africa (SSA), yet surprisingly low numbers of GCAs are reported in the region. A similar phenomenon is seen with the inflammatory bowel diseases (IBD), Crohn's disease, and ulcerative colitis. These disorders have risen dramatically over the past century in high income countries across the globe, with sharp increases noted more recently in newly industrialized regions. In contrast IBD is rare in most regions in SSA. For both diseases this may reflect under-reporting or limited access to diagnostic modalities, but an alternative explanation is the high burden of infection with gastrointestinal parasites endemic to SSA which may attenuate the risk of developing GCA and IBD. In this mini review we discuss the complex interplay between these microorganisms, GCA, and IBD, as well as a possible protective role of H. pylori and the development of IBD.

Stool Antigen Examination as a Diagnostic Tool for Dyspeptic Patient caused by Helicobacter pylori Infection: A Case-based Literature Review

Today, the gold standard for diagnosing H. pylori infection is by Urea Breath Test (UBT). However, UBT tests are not widely available in several remote areas in Indonesia. Stool antigen test (SAT) is an alternative diagnostic test for H. pylori infection. However, it is unclear whether the performance of the SAT to diagnose H. pylori infection can be comparable with UBT accuracy. This report was aimed to determine the accuracy of the stool antigen test (SAT) to diagnose H. pylori infection as an alternative to the urea breath test (UBT). Our case-based literature review indicates that the SAT has high sensitivity (79%-96.4%). Therefore stool antigen tests can help doctors in ruling out H. pylori infection. SAT also demonstrates remarkable specificity of stool antigen examination (98.6%-100%), suggesting that stool antigen tests can help doctors rule in H. pylori infection.

A Scoping Review of the Health of African Immigrant and Refugee Children

Migration is a growing phenomenon around the world, including within the African continent. Many migrants, especially African children, face challenges related to health and social inclusion and can face increased health risks. A systematic scoping review of available literature on the health of African migrant children across the globe was conducted to offer insight into these health risks. The review was conducted over a 15-month period from January 2019 to April 2020, yielding 6602 articles once duplicates were removed. This search included electronic databases, reference lists of articles reviewed, and searches of libraries of relevant organisations. A total of 187 studies met the inclusion criteria, of which 159 were quantitative, 22 were qualitative, and 6 used mixed methods. The findings reveal decreased health in this population in areas of nutrition, infectious diseases, mental health, birth outcomes, sexual and reproductive health, physical and developmental health, parasitic infections, oral health, respiratory health, preventative health, endocrine disorders, health care services, and haematological conditions. The findings offer insights into factors influencing the health of African immigrant and refugee children. Further studies, especially qualitative studies, are needed to determine barriers to service access after migration and to investigate other underexplored and overlooked health concerns of African migrant children, including pneumonia and child maltreatment.

Health needs of refugee children identified on arrival in reception countries: a systematic review and meta-analysis

BACKGROUND

The worldwide number of refugees has considerably increased due to ongoing wars, national instability, political persecution and food insecurity. In Europe, about one-third of all refugees are children, an increasing number of which are travelling alone. There are often no systematic medical health assessments for these refugee children on entry in reception countries despite the fact that they are recognised as an at-risk population due to increased burden of physical and mental health conditions. We aimed to perform a systematic review of the literature to describe the health status of refugee children on entering reception countries.

METHODS

A systematic search of published literature was conducted using the terms refugee, immigrant or migrant, medical or health, and screening.

RESULTS

Of the 3487 potentially relevant papers, 53 population-based studies were included in this review. This systematic review showed that refugee children exhibit high estimated prevalence rates for anaemia (14%), haemoglobinopathies (4%), chronic hepatitis B (3%), latent tuberculosis infection (11%) and vitamin D deficiency (45%) on entry in reception countries. Approximately one-third of refugee children had intestinal infection. Nutritional problems ranged from wasting and stunting to obesity.

CONCLUSIONS

Refugee children entering reception countries should receive comprehensive health assessments based on the outcomes of this systematic review, national budgets, cost-effectiveness and personal factors of the refugees. The health assessment should be tailored to individual child health needs depending on preflight, flight and postarrival conditions.A paradigm shift that places focus on child health and development will help this vulnerable group of children integrate into their new environments.

PROSPERO REGISTRATION NUMBER

122561.

Prevalence of Helicobacter pylori infection among preschool children in Latvia: no significant decrease in prevalence during a ten year period

Aims: Published data show a trend of decreasing prevalence of Helicobacter pylori in Eastern European countries due to socioeconomic changes. The aim of this study was to determine the prevalence of H. pylori infection among children in Latvia and to compare these results with previous studies in the same population. The risk factors associated with infection were also analysed. Methods: Preschool children in kindergartens and primary health care centres were investigated using a stool antigen test. Their parents were asked to fill out a questionnaire about possible risk factors. Statistical analysis included Pearson’s χ2 test and linear regression analysis. Results: The prevalence of H. pylori infection determined by the monoclonal stool antigen test in children aged 1–6 years (median 5 years) was 15.5% (15/101) (95% confidence interval 8.67–23.48%). In the regression analysis, H. pylori positivity was significantly negatively associated with the consumption of imported fruit at least once per week ( p=0.02). Conclusions: The prevalence of H. pylori in the studied population has not decreased significantly during the last decade and is still associated with socioeconomic factors. The role of some dietary factors (e.g. the consumption of fruit) in the spread of infection should be studied further.

Serologic evidence that ascaris and toxoplasma infections impact inflammatory responses to Helicobacter pylori in Colombians

BACKGROUND

Helicobacter pylori-infected children from coastal Tumaco, Colombia, have more parasitism, and adults have lower gastric cancer risk compared with high-altitude Pasto/Tuquerres residents. Because helminth and Toxoplasma gondii infections alter helicobacter gastritis in rodent models, we determined whether seropositivity to Ascaris lumbricoides or T. gondii was associated with Th2-IgG1 or Th1-IgG2 responses to H. pylori.

METHODS

Sera (240) from the two populations were evaluated for A. lumbricoides and T. gondii seropositivity and results correlated with IgE and IgG isotype responses to H. pylori.

RESULTS

Most Tumaco children and adults were seropositive for A. lumbricoides (89%, 66%), T. gondii (59%, 98%), or both (45%, 66%). In contrast, seropositivity among Pasto/Tuquerres children was much lower (9%A. lumbricoides, 11%T. gondii, and 2% dual positive) but increased in adults (58%A. lumbricoides, 82%T. gondii, and 41% dual positive). A. lumbricoides seropositivity correlated with elevated IgE and anti-inflammatory Th2-IgG1 responses to H. pylori, while T. gondiigondii seropositivity was linked to elevated IgE, pro-inflammatory Th1-IgG2, IgG3, and IgG4 responses to H. pylori. Individuals with high T. gondii titers had reduced Th1-IgG2, IgG3, and IgG4 responses to H. pylori.

CONCLUSIONS

Results support regional differences for childhood parasitism and indicate A. lumbricoides and T. gondii infections may impact inflammatory responses to H. pylori and partially explain differences in gastric cancer risk in Colombia.

Coinfection of Schistosoma (Trematoda) with bacteria, protozoa and helminths

This review examines coinfection of selected species of Schistosoma with bacteria, protozoa and helminths and focuses on the effects of the coinfection on the hosts. The review is based mainly on tables that contain the salient information on the coinfecting organisms in vertebrate hosts. Further explanation and clarification of the tables are given in the text. A table is also provided that gives synoptic information on the 37 species in the 19 genera considered in this review. Coinfection studies with Schistosoma species and the other organisms were considered in six tables plus the accompanying text. Considerations of the Schistosoma interactions with another species of organism include studies on coinfection with Plasmodium, with protozoa other than Plasmodium; with Salmonella, with bacteria other than Salmonella; and with Fasciola, with helminths other than Fasciola. Numerous factors were found to influence the effects of coinfection on the vertebrate host, including organisms and hosts used in the studies, order and time interval between the first and the second infection, studies on natural versus experimental hosts, dosage of the infectious agents, strains and pedigrees of the parasites, age of hosts at time of exposure to the infectious agents and age of hosts at the time of necropsy. Overall, a prior infection with Schistosoma, particularly a patent infection, often has an effect on the subsequent infection by a protozoan, bacterium or other helminth. In relatively few cases, a prior infection with Schistosoma decreased the severity of the subsequent infection as with Helicobacter pylori, Fasciola hepatica, Echinostoma or Plasmodium, the latter only exhibiting this behaviour when coinfected with Schistosoma haematobium. More often, however, a prior infection with Schistosoma increased the severity of the second infection as with Leishmania, Toxoplasma gondii, Entamoeba histolytica, Staphylococcus aureus or Salmonella. In some of these coinfection studies, the increased severity of the subsequent infection was associated with a specific, prolonged form of the disease in humans, which has implications for patient treatment and recovery. Additional research is needed, particularly on Schistosoma coinfections which currently have a small body of research and are current problems in human populations. Examples of such Schistosoma interactions include the genera of Mycobacteria, Leishmania, Staphylococcus, Necator and Strongyloides. Hopefully, future studies will elucidate valuable new information on the interesting subject of coinfection of Schistosoma with other organisms.

Impact of chronic Helicobacter pylori infection on Alzheimer's disease: preliminary results

Recent case-control studies reported an association between H. pylori infection and Alzheimer's disease (AD). Our aim was to compare cognitive impairment, neuroinflammation, and cerebrovascular lesion load in a group of AD patients according to their H. pylori status. For the 53 AD patients included, we assessed: clinical data (vascular comorbidities and cognitive assessment), biological data (especially fibrinogen, homocysteine levels, apolipoprotein E4 genotype; cerebrospinal fluid [CSF] total tau protein [Tau], phospho-tau(181) protein [pTau(181)]), and amyloid beta peptide levels, serum/CSF-cytokines (interleukin [IL]-1β, IL-6, IL-8, tumor necrosis factor [TNF]-α) and pepsinogen I/pepsinogen II (PgI/PgII) ratio, and cerebrovascular lesion load (magnetic resonance imaging [MRI] fluid-attenuated inversion recovery [FLAIR] with the Fazekas and Schmidt scale). H. pylori infection was diagnosed by enzyme-linked immunosorbent assay (ELISA) and immunoblot test. H. pylori infection was associated with a decreased Mini Mental State Examination (MMS) (p = 0.024), and higher CSF pTau(181) (p = 0.014) and tau (p = 0.021) levels. A decreased PgI/II ratio (i.e., an increased gastric atrophy) was associated with the infection (p = 0.005). Homocysteine levels were positively correlated to Fazekas score (r = 0.34; p = 0.032) and to H. pylori immunoglobulin (Ig)G levels (r = 0.44; p = 0.001). Higher CSF cytokine levels (IL-8, p = 0.003; TNF-α, p = 0.019) were associated with the infection, but systemic inflammation results were controversial. Finally, in multivariate analysis, a lower MMSE score (odds ratio [OR], 0.83 [0.72-0.97]; p = 0.017), plasma IL-1β level (OR, 0.31 [0.11-0.87]; p = 0.025), an increased gastric atrophy, i.e., a lower PgI/PgII ratio (OR, 0.63 [0.43-0.93]; p = 0.020) were still associated with the infection. AD patients infected by H. pylori tended to be more cognitively impaired. Studies are needed to attest to the impact of H. pylori infection on AD course, especially on cerebrovascular lesions and neuroinflammation.

Epidemiology of Helicobacter pylori infection and public health implications

This review summarizes studies on the epidemiology and public health implications of Helicobacter pylori published in peer-reviewed journals from April 2010 through March 2011. Prevalence rates vary widely between different geographical regions and ethnic groups. An interesting study from the USA identified the degree of African ancestry as an independent predictor of H. pylori infection. Two studies have demonstrated early childhood as the period of transmission of infection and identified an infected sibling as an important risk factor. An oral-oral route of spread has been substantiated with several studies showing the presence of H. pylori in the oral cavity. Studies have shown the presence of H. pylori in drinking water and the role of poor living conditions and sanitation in H. pylori infection, supporting an oral-fecal route of spread. Screening for H. pylori as a gastric cancer pre-screening strategy has been described in Japan, and the importance of H. pylori eradication as a gastric cancer-prevention strategy has now been further emphasized in Japanese guidelines. Two studies have shown a decrease in the burden of dyspepsia and peptic ulcer disease with H. pylori eradication.

Epidemiology of Helicobacter pylori infection and public health implications

This review summarizes studies on the epidemiology and public health implications of Helicobacter pylori published in peer-reviewed journals from April 2010 through March 2011. Prevalence rates vary widely between different geographical regions and ethnic groups. An interesting study from the USA identified the degree of African ancestry as an independent predictor of H. pylori infection. Two studies have demonstrated early childhood as the period of transmission of infection and identified an infected sibling as an important risk factor. An oral-oral route of spread has been substantiated with several studies showing the presence of H. pylori in the oral cavity. Studies have shown the presence of H. pylori in drinking water and the role of poor living conditions and sanitation in H. pylori infection, supporting an oral-fecal route of spread. Screening for H. pylori as a gastric cancer pre-screening strategy has been described in Japan, and the importance of H. pylori eradication as a gastric cancer-prevention strategy has now been further emphasized in Japanese guidelines. Two studies have shown a decrease in the burden of dyspepsia and peptic ulcer disease with H. pylori eradication.

Helicobacter pylori in pediatrics

This article reviewed the important publications on Helicobacter pylori research with children between April 2010 and March 2011. The most interesting studies in the last year lend further weight to the evidence for vertical transmission of H. pylori. The discovery of a potential role for jhp0562, the gene which encodes for the cell envelope protein glycosyltransferase, in the progression to peptic ulcer disease is also very interesting as it may provide a novel way to distinguish children at risk of peptic ulcer disease from those who are not, and so determine those who requires treatment to eradicate H. pylori. The rise in non-H. pylori-associated ulcers and erosions continues to be reported with no apparent risk factors for these ulcers identified to date. High levels of treatment failure continue to be reported, and there remains an urgent need for more effective treatment regimes for children.