Nutritional status of Helicobacter pylori-infected children in Guatemala as compared with uninfected peers

Helicobacter pylori infection is associated with fecal biomarkers of environmental enteric dysfunction but not with the nutritional status of children living in Bangladesh

Background

Because Helicobacter pylori (H. pylori) infection and Environmental Enteric Dysfunction (EED) follow a similar mode of transmission, there can be a complex interplay between H. pylori infection and EED, both of which can influence childhood growth. We sought to investigate the factors associated with H. pylori infection and identify its relationship with the fecal biomarkers of EED including Myeloperoxidase (MPO), Neopterin (NEO), Calprotectin, Reg1B and Alpha-1 antitrypsin (AAT), and nutritional status of the children.

Methodology

Data from an on-going community-based nutrition intervention study was used for this analysis. Total 319 children aged between 12–18 months were evaluated at enrolment and at the end of a 90-day nutrition intervention. Multivariable linear regression with generalized estimating equations was done to examine the association of H. pylori infection with stool biomarker of EED and nutritional status of the children.

Principal findings

One-fifth of the participants had H. pylori infection at both the time points, with 13.8% overall persistence. Children living in crowded households had higher odds of being infected by H. pylori (AOR = 2.02; 95% CI = 1.02, 4.10; p-value = 0.045). At enrolment, 60%, 99%, 69% and 85% of the stool samples were elevated compared to the reference values set for MPO, NEO, AAT and Calprotectin in the non-tropical western countries. The proportions reduced to 52%, 99%, 67%, and 77% for the same biomarkers after the nutrition intervention. Infection with H. pylori had significant positive association with fecal AAT concentrations (Coefficient = 0.26; 95% CI = 0.02, 0.49; p-value = 0.03) and inverse relationship with Reg1B concentrations measured in the stool samples (Coefficient = -0.32; 95% CI = -0.59, -0.05; p-value = 0.02). However, H. pylori infection was not associated with the indicators of childhood growth.

Conclusions

The study findings affirmed that the acquisition and persistence of H. pylori infection in the early years of life may exert an adverse impact on intestinal health, induce gut inflammation and result in increased intestinal permeability.

Infection with H. pylori, a substantial public health burden in the tropical countries, follows the similar mode of transmission analogous to Environmental Enteric Dysfunction (EED). There can be a complex interplay between H. pylori infection and EED–both of which can influence childhood growth–but the definite role of H. pylori infection contributing to EED and subsequent growth failure is poorly understood. In this study, the authors present data from an ongoing community-based nutrition intervention study and investigated the factors associated with H. pylori infection and identify its relationship with fecal biomarkers of EED and indicators of the nutritional status of the children hailing from a resource-poor urban settlement. They demonstrated the acquisition and persistence of H. pylori infection during early childhood. The study results also corroborate that infection with H. pylori had significant positive association with fecal Alpha-1 antitrypsin concentrations and an inverse relationship with Reg1B concentrations measured in stool samples of the children. The findings revealed in this study may contribute to a better understanding of the role of H. pylori infection in contributing to EED as well as alteration of gut function in the early years of life.

Seroprevalence of Helicobacter pylori/CagA Antibodies in Guatemalan Gastric Cancer Patients: Association of Seropositivity with Increased Plasma Levels of Pepsinogens but not Soluble Urokinase Plasminogen Activator Receptor

Infection by Helicobacter pylori is a major risk factor for gastric cancer (GC), the second leading cause of cancer-related death worldwide. Although biomarkers such as pepsinogens (PGs) and soluble urokinase plasminogen activator receptor (suPAR) may have diagnostic and/or prognostic value in patients with GC, their levels may be affected by H. pylori infection. The aim of this study was to investigate the association of the presence of antibodies to H. pylori and cytotoxin-associated gene A (CagA) with plasma levels of PGs and suPAR in a cohort of Guatemalan GC patients and controls. To this end, levels of suPAR, Pepsinogens I and II (PGI and PGII), and antibodies to H. pylori and CagA toxin were determined by ELISA in plasma samples from 67 GC patients and 136 matched healthy controls. Seropositivity for CagA was significantly higher in patients with GC than in controls. Pepsinogens II and suPAR levels were higher and PGI/PGII ratios were lower in GC patients than in controls. There was a significant association of H. pylori seropositivity status with increased levels of PGII and lower PGI/PGII ratios, particularly in the control (non-GC) population. The levels of suPAR were not significantly affected by H. pylori or CagA seropositivity status. These results suggest that the seropositivity status for H. pylori and CagA need to be taken into account during the GC diagnostic process.

Helicobacter pylori Infection in Malnourished Children in Lagos

Background/Aim:

Helicobacter pylori infection is acquired in childhood, but there are conflicting reports on malnutrition and the infection. This study aimed to determine the prevalence of H. pylori infection among malnourished children and highlight the socioeconomic (SE) and clinical factors associated with the infection.

Methodology:

This was a descriptive cross-sectional study of 122 malnourished children and 120 healthy controls. Anthropometry was done for all the study participants, and the H. pylori status was determined with the use of monoclonal stool antigen test in all the participants. Logistic regression analysis was used to determine the factors that could predict the occurrence of the infection in the children.

Results:

Seventy percent (70.8%) of the malnourished children had moderate malnutrition, whereas 29.2% were severely malnourished. The prevalence of H. pylori in the malnourished children was 22.8% compared to 32.5% in the controls (P = 0.09). The infection was most prevalent in toddlers (60.7%). The SE class was significantly related to the infection (P = 0.01) and about a fifth (21.3%) of the malnourished children who belonged to the low SE class were H. pylori positive compared to 9.2% of the controls. About 64.3% of the malnourished children with H. pylori infection had fever and 25.8% had diarrhea. Multivariate analysis showed that stunting was significantly related to the infection (P = 0.02).

Conclusion:

H. pylori infection was prevalent among the toddlers and was significantly associated with stunting in this cohort of malnourished children. Screening of children for the infection is still advocated, and infected children should be referred for appropriate treatment and follow-up. The relationship between SE class and the infection still requires further research.

Where are we today with Helicobacter pylori infection among healthy children in Saudi Arabia?

BACKGROUND/AIMS

The available studies on Helicobacter pylori (H. pylori) prevalence among healthy asymptomatic population across Saudi Arabia suffers from significant limitations. We conducted this large population-based study to estimate the H. pylori seropositivity rate among apparently healthy children in Saudi Arabia, using anti-H. pylori immunoglobulin A (IgA) and IgG serology tests, and to study the influence of H. pylori infection on growth.

MATERIALS AND METHODS

We conducted a cross-sectional study to screen apparently healthy school aged Saudi children (aged 6-15 years), attending primary and intermediate schools in Riyadh between 2014 and 2016, for H. pylori seropositivity by checking for the presence of anti-H. pylori IgG and IgA antibodies in serum specimens.

RESULTS

Out of 3551 serum specimens, 1413 cases tested seropositive for H. pylori organism (40%): 430 (12.2%) were both IgG and IgA positive, 212 (6%) and 771 (21.7%) cases showed isolated positivity for IgG or IgA, respectively. Male gender, older age, lower levels of socioeconomic status (SES), and family members >10 were significantly associated with H. pylori seropositivity. The proportion of participants with short stature was significantly more in the H. pylori seropositive group than the seronegative group (OR1.249, confidence interval [1.020-1.531], P= 0.033). There was no significant association between H. pylori seropositivity and gastrointestinal symptoms.

CONCLUSION

The prevalence of H. pylori seropositivity among apparently healthy Saudi children (40%) is intermediate compared with that in developed and developing countries. The Saudi pediatric population shows a predominant IgA-type immunological response to H. pylori infection.

Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

BACKGROUND

Helicobacter pylori infection has been associated with early childhood growth impairment in high- and middle-income countries; however, few studies have examined this relationship within low-income countries or have used a longitudinal design. The possible effects of H. pylori infection on growth trajectories were examined in a cohort of young Ethiopian children.

METHODS

In 2011/12, 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were followed up at age 6.5 years. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Height and weight were measured twice, and the average of the two measurements was used. Exposure to H. pylori infection was assessed using a rapid H. pylori stool antigen test. The independent associations of positive H. pylori infection status (measured at ages 3 and 6.5 years) with baseline height and weight (age 3 years) and height and weight growth trajectory (from age 3 to 6.5 years) were modelled using hierarchical linear models.

RESULTS

At baseline (age 3 years), the children's mean height was 85.7cm and their mean weight was 11.9kg. They gained height at a mean rate of 8.7cm/year, and weight at a mean rate of 1.76kg/year. H. pylori infection was associated with lower baseline measurements and linear height trajectory (β=-0.74cm and -0.79cm/year, respectively), after controlling for demographics and markers of socio-economic status. However, the positive coefficient was associated with quadratic growth in height among H. pylori-infected children (β=0.28, 95% confidence interval 0.07 to 0.49, p<0.01), and indicated an increase in height trajectory as the child increased in age. A non-significant difference in baseline and trajectory of weight was observed between H. pylori-infected and non-infected children.

CONCLUSIONS

These findings add to the growing body of evidence supporting that H. pylori infection is inversely associated with childhood growth trajectory, after controlling for a range of factors associated with reduced growth and H. pylori status. Further follow-up will be important to confirm possible catch-up in height trajectory among H. pylori-infected children as they grow older.

Helicobacter pylori Infection and Children's Growth: An Overview

OBJECTIVES

Helicobacter pylori infection is acquired in early childhood, yet its role in children's health is still not fully clear. In this narrative review, we focused on the association between H pylori infection and children's growth.

METHODS

A literature search of the Ovid MEDLINE (till June 2015) and EMBASE (till August 2015) databases was performed using the terms "Helicobacter pylori, growth, body height, growth disorders and child development." Original studies that addressed the association between H pylori infection or eradication and children's growth were reviewed and the risk of bias of each study was assessed.

RESULTS

The existing evidence is based on observational studies (N = 48) and suggests that H pylori infection may adversely influence children's growth; findings were more consistent across studies with low risk of bias. Regarding linear growth, observational studies have repeatedly linked between H pylori infection and slower or diminished linear growth; yet, it is not known whether this association is causal. The association between H pylori infection and ponderal growth has been less consistent. Scarce evidence exists on the effect of H pylori eradication on children's skeletal growth and weight gain, but there is an indication that H pylori eradication may benefit nutritional status.

CONCLUSIONS

H pylori infection may impair children's growth. Additional studies, especially clinical trials, are needed to elucidate the role of H pylori eradication in children's growth, and the mechanisms that may be involved in such.

Helicobacter pylori Infection in Early Childhood and Growth at School Age

BACKGROUND

There are conflicting results regarding the role of H. pylori in children's growth. We examined differences in growth indices at school age according to H. pylori infection acquisition in preschool age.

MATERIALS AND METHODS

A prospective study was undertaken between 2004 and 2009, in which of healthy children (N = 139, ages 3-5 years at baseline) were tested for the presence of H. pylori antigen in their stool using enzyme-linked immunoassay and followed-up till age 6-9 years (median follow-up time 45 months). Height, weight, and hemoglobin levels were measured, and socioeconomic data were obtained. Z scores of height for age, weight for age, and body mass index for age at baseline and follow-up were calculated using the 2000 Center for Disease Control and Prevention growth reference curves. Growth velocity (cm/month) between preschool and school age was compared between H. pylori-infected and uninfected children using mixed models.

RESULTS

Fifty-three percent of the children were H. pylori positive at baseline, and all except one child tested positive at follow-up. The adjusted mean Z score of height for age at follow-up was significantly lower among H. pylori-infected children than uninfected ones: 0.15 (95% confidence intervals (CIs) 0.02, 0.29) and 0.45 (95% CI 0.29, 0.60), respectively (p = .002). Growth velocity was slower in the former group -0.0264 cm/month (95% CI -0.047, -0.005) (p = .014), after adjusting for baseline height and age. H. pylori infection was not associated with body weight.

CONCLUSIONS

Helicobacter pylori infection acquired in early childhood may have long-term adverse influence on linear growth at school age.

Dietary and anthropometric indicators of nutritional status in relation to Helicobacter pylori infection in a paediatric population. Br J Nutr. 2015;113:1113-1119. [PMID: 25761510 DOI: 10.1017/s0007114515000483]

It has been postulated that Helicobacter pylori infection could affect growth and appetite, consequently influencing body weight. Therefore, the association between H. pylori infection and the dietary and anthropometric indicators of nutritional status of a paediatric population were investigated. A total of 525 children (aged 4-16 years) who were referred to the gastroenterology unit of the Sor Maria Ludovica Children's Hospital from Buenos Aires, Argentina, were enrolled and completed an epidemiological questionnaire. H. pylori infection was diagnosed using the ¹³C-urea breath test (¹³C-UBT). Height and weight were assessed for calculation of anthropometric indicators. Energy and macronutrient intakes were estimated by 24 h dietary recall. Data analysis was performed using a χ² test, a Student's t test, a Mann-Whitney U test and linear and logistic regressions. The prevalence of H. pylori infection was 25·1 % (with a mean age of 10·1 (SD 3·1) years). A tendency towards lower energy, carbohydrate, protein and fat intakes was observed in infected patients; however, it was not associated with H. pylori infection in any of the evaluated age groups (4-8, 9-13 and 14-16 years). Underweight, stunting, overweight and obesity were also not associated with the infection. Although height-for-age and BMI-for-age Z scores tended to be lower in infected patients, the differences between H. pylori-positive and H. pylori-negative children were not statistically significant. In conclusion, H. pylori infection was not associated with dietary intake or with anthropometric indicators in the present population of children with gastrointestinal symptoms; however, an increased sample size would be needed to confirm the observed tendency towards lower dietary intake and lower anthropometric indicators of nutritional status in H. pylori-infected children.

Unintended consequences of Helicobacter pylori infection in children in developing countries: iron deficiency, diarrhea, and growth retardation

Helicobacter pylori infection is predominantly acquired early in life. The prevalence of the infection in childhood is low in developed countries, whereas in developing countries most children are infected by 10 y of age. In poor resource settings, where malnutrition, parasitic/enteropathogen and H. pylori infection co-exist in young children, H. pylori might have potentially more diverse clinical outcomes. This paper reviews the impact of childhood H. pylori infection in developing countries that should now be the urgent focus of future research. The extra-gastric manifestations in early H. pylori infection in infants in poor resource settings might be a consequence of the infection associated initial hypochlorhydria. The potential role of H. pylori infection on iron deficiency, growth impairment, diarrheal disease, malabsorption and cognitive function is discussed in this review.

Effect of Helicobacter pylori infection on growth velocity of school-age Andean children

BACKGROUND

Helicobacter pylori infection affects about half of the world's population and is usually acquired in childhood. The infection has been associated with chronic gastritis, peptic ulcer, and stomach cancer in adulthood. Little is known, however, about its consequences on child health. We examined the effect of H. pylori infection on growth among school-age children in the Colombian Andes by comparing growth velocity in the presence and absence of H. pylori infection.

METHODS

Children who were 4-8 years old in 2004 were followed up in a community where infected children received anti-H. pylori treatment (n = 165) and a comparison community (n = 161) for a mean of 2.5 years. Anthropometry measurements were made every 3 months and H. pylori status ascertained by urea breath test every 6 months. Growth velocities (cm/month) were compared across person-time with and without infection, using mixed models for repeated measures.

RESULTS

In the untreated community, 83% were H. pylori-positive at baseline and 89% were -positive at study end. The corresponding prevalences were 74% and 46%, respectively, in the treated community. Growth velocity in the pretreatment interval was 0.44 (standard deviation [SD] = 0.13) cm/month. Models that adjusted for age, sex, and height estimated that H. pylori-positive children grew on average 0.022 cm/month (95% confidence interval = 0.008 to 0.035) slower than H. pylori-negative children, a result that was not appreciably altered by adjustment for socioenvironmental covariates.

CONCLUSIONS

This study suggests that chronic H. pylori infection is accompanied by slowed growth in school-age Andean children.

Effect of Helicobacter pylori infection on growth velocity of school-age Andean children

BACKGROUND

Helicobacter pylori infection affects about half of the world's population and is usually acquired in childhood. The infection has been associated with chronic gastritis, peptic ulcer, and stomach cancer in adulthood. Little is known, however, about its consequences on child health. We examined the effect of H. pylori infection on growth among school-age children in the Colombian Andes by comparing growth velocity in the presence and absence of H. pylori infection.

METHODS

Children who were 4-8 years old in 2004 were followed up in a community where infected children received anti-H. pylori treatment (n = 165) and a comparison community (n = 161) for a mean of 2.5 years. Anthropometry measurements were made every 3 months and H. pylori status ascertained by urea breath test every 6 months. Growth velocities (cm/month) were compared across person-time with and without infection, using mixed models for repeated measures.

RESULTS

In the untreated community, 83% were H. pylori-positive at baseline and 89% were -positive at study end. The corresponding prevalences were 74% and 46%, respectively, in the treated community. Growth velocity in the pretreatment interval was 0.44 (standard deviation [SD] = 0.13) cm/month. Models that adjusted for age, sex, and height estimated that H. pylori-positive children grew on average 0.022 cm/month (95% confidence interval = 0.008 to 0.035) slower than H. pylori-negative children, a result that was not appreciably altered by adjustment for socioenvironmental covariates.

CONCLUSIONS

This study suggests that chronic H. pylori infection is accompanied by slowed growth in school-age Andean children.

Consequences of Helicobacter pylori infection in children

Although evidence is emerging that the prevalence of Helicobacter pylori (H. pylori) is declining in all age groups, the understanding of its disease spectrum continues to evolve. If untreated, H. pylori infection is lifelong. Although H. pylori typically colonizes the human stomach for many decades without adverse consequences, children infected with H. pylori can manifest gastrointestinal diseases. Controversy persists regarding testing (and treating) for H. pylori infection in children with recurrent abdominal pain, chronic idiopathic thrombocytopenia, and poor growth. There is evidence of the role of H. pylori in childhood iron deficiency anemia, but the results are not conclusive. The possibility of an inverse relationship between H. pylori and gastroesophageal reflux disease, as well as childhood asthma, remains a controversial question. A better understanding of the H. pylori disease spectrum in childhood should lead to clearer recommendations about testing for and treating H. pylori infection in children who are more likely to develop clinical sequelae.

Body indices and basic vital signs in Helicobacter pylori positive and negative persons

It has been hypothesized that Helicobacter pylori (Hp) infection may contribute to reduced stature, risk of hypertension or obesity. The aim was to evaluate body indices in Hp positive and negative persons. A total of 2436 subjects (4–100 years old) were tested for Hp status by ¹³Curea breath test. Data on height and weight were collected for 84%, and blood pressure for 80% of the study subjects. The prevalence of Hp infection was 41.6%. The odds ratio for a 10-year increase in age was 1.21 (95% CI 1.17–1.25, p-value <0.001). Statistically significant negative association of Hp positivity with body height was most pronounced in the younger age groups, while a positive association of Hp positivity with body mass index was only seen in those aged 15+ years. There was a negative effect of Hp positivity on systolic and diastolic blood pressure in subjects below 25 and a relatively strong positive effect on blood pressure in subjects over 65 years. Residual confounding by social characteristics as a possible explanation for the associations of Hp positivity with height and blood pressure cannot be excluded. Unmeasured factors related to social and family environment may cause the apparent association between Hp positivity and children’s growth and blood pressure.

The association between Helicobacter pylori infection and adult height

OBJECTIVES

A cross-sectional survey was performed to evaluate the association between H. pylori and adult height.

METHODS

H. pylori infection was assessed using a 13C-urea breath test and height measured by a research nurse using a stadiometer in participants between the ages of 40-49 years.

RESULTS

Height was measured in 2932/3682 participants that attended and were evaluable. H. pylori infected women were 1.4 cm shorter than uninfected women (95% confidence interval, CI = 0.7-2.1 cm) and this statistically significant difference persisted after adjusting for age, ethnicity, childhood and present socio-economic status (H. pylori positives 0.79 cm shorter; 95%CI: 0.05-1.52 cm). H. pylori positive men were 0.7 cm shorter than uninfected men but this did not reach statistical significance (95% CI: -0.1-1.5 cm).

CONCLUSION

Although H. pylori infection is associated with reduced adult height in women, this maybe due to residual confounding.

Prevalence of Helicobacter pylori infection in children from an urban community in north-east Brazil and risk factors for infection

OBJECTIVES

To investigate the prevalence of Helicobacter pylori infection in a randomly selected population of children from a low income community in Brazil and the risk factors for infection.

DESIGN

A cross-sectional, randomised study of prevalence and risk factors.

SUBJECTS

Children living in an urban community in north-east Brazil.

METHODS

H. pylori infection was determined using the C-urea breath test. Risk factors were assessed using a structured interview schedule.

RESULTS

The overall prevalence of H. pylori was 56% (197/353). The infection was most common for those aged 12-14 years. In this group 75.4% (49/65) (95% CI, 63.1-85) of all children were positive for H. pylori, while in children less than 2 years of age 35.1% (13/37) (95% CI, 20.2-52.5) were positive. The prevalence of H. pylori increased significantly with age (P < 0.0001). In the bivariate analysis, a significant difference was found in the prevalence of H. pylori infection and age, number of persons per room, the number of children per household, cup sharing, and type of drinking water (P < 0.05). However, after logistic regression modelling only age (odds ratio (OR) = 1.3; 95% confidence interval (CI), 1.07-1.65), and number of persons per room (OR = 2.58; 95% CI, 1.4-4.6) were risk factors for H. pylori infection.

CONCLUSIONS

H. pylori is highly prevalent among children in a north-eastern Brazilian community characterised by poor living conditions, and this infection is largely acquired during early childhood. The infection increased with age, and domestic overcrowding. Further longitudinal studies must examine in depth the possible modes of transmission of the organism in young children.

Serologic prevalence of antibodies to Helicobacter pylori in internationally adopted children

BACKGROUND

Helicobacter pylori (H. pylori) infection has been linked to gastritis, diarrhea, peptic ulcers, failure-to-thrive, anemia, as well as predisposition to gastric malignancies. Because many internationally adopted children have diarrhea, failure-to-thrive, and anemia on arrival to the US, we determined the prevalence of HP antibodies among these children.

METHODS

Serum samples from 226 unselected children from 18 countries who were evaluated in the International Adoption Clinic at New England Medical Center were tested for antibodies to H. pylori. The results of serologic screening were analyzed in relation to age at adoption, site of residence prior to adoption, weight and height, and the presence or absence of anemia, diarrhea, or intestinal parasites.

RESULTS

31% of internationally adopted children had antibodies to H. pylori. The presence of H. pylori-antibodies was associated with residence in an orphanage (vs. foster care) prior to adoption, older age at adoption, and coinfection with intestinal parasites. No direct effects on height or weight were identified; no associations with diarrhea or anemia were found.

CONCLUSIONS

Internationally adopted children have a high incidence of exposure to H. pylori, as diagnosed serologically. Residence in an orphanage (compared with foster care), older age at adoption, and coinfection with intestinal parasites were more common among children seropositive for anti-H. pylori antibodies.

Growth slowing after acute Helicobacter pylori infection is age-dependent

OBJECTIVE

Most infections occur during childhood, but the health effects of childhood infection are poorly understood. We investigated whether growth decreases in the 2 months after acute seroconversion.

METHODS

We performed a nested case-control study among children 6 months to 12 years of age in a community on the outskirts of Lima, Peru. Health interviews were completed daily. Anthropometric measurements were taken monthly. Sera were collected every 4 months and tested for immunoglobulin G. Two-month height and weight gains of seroconverters were compared with gains of sex, age, and size-matched seronegative controls.

RESULTS

In the 2 months after infection, 26 seroconverters gained a median of 24% less weight than 26 matched controls (interquartile range, 63% less to 21% more). In multivariate analysis, infection attenuated weight gain only among children aged 2 years or older. This decrease was not explained by increased diarrhea.

CONCLUSIONS

seroconversion is associated with a slowing of weight gain in children aged 2 years or older. Reasons for this finding merit additional study.

The role of Helicobacter pylori in paediatrics

Helicobacter pylori is a bacterium that colonizes the human stomach, especially during childhood. Although it has been studied intensively during the past decade, many controversies still exist on many important issues, including the clinical relevance of virulence factors, indications for treatment, recommended procedures for diagnosis and the typical symptom profile, among others. The lack of double-blind, placebo-controlled studies in children illustrates the paucity of hard scientific data, and is the major reason for differences in opinion. Therefore, the present review of literature published during the past 2 years raises many questions.

Gastrointestinal infections in children

Gastrointestinal infections in children are a major cause of morbidity and mortality worldwide. Children living in developing countries are particularly susceptible to infectious diarrhea because of poor standards of hygiene and sanitation. Although the magnitude of diarrheal illnesses in developed countries is less, costly hospital admissions are still frequent. The causal agent of infectious diarrhea is most frequently related to age, geographical location, lifestyle habits, use of antibiotics, associated medical conditions, social circumstances, and degree of immune competence. In this article we present some of the most important articles published in the field during the last year. The role of Helicobacter pylori in the pathogenesis of gastritis and peptic ulcer disease has been shown in adults and children. Information about the natural history of H. pylori, symptomatology, and diagnostic therapeutic approaches for children are being generated constantly; we discuss some of the most relevant information in this review.

Virulence factors of Helicobacter pylori responsible for gastric diseases in Mongolian gerbil

Helicobacter pylori infection induces various gastroduodenal diseases. We examined the role of two genes, vacA and cagE, in the gastric pathogenesis induced by H. pylori using a long-term (62 wk) animal model. Reportedly, both genes are associated with the virulence of H. pylori: vacA encodes vacuolating cytotoxin, and cagE, with other genes in the cag pathogenicity islands, encodes a type IV secretion system. Mongolian gerbils were challenged in this study by a wild-type TN2 strain and its isogenic mutants of cagE or vacA. The wild-type and vacA mutants induced severe gastritis, whereas cagE mutants induced far milder changes. Gastric ulcer was induced at the highest rate (22/23) by the wild-type TN2, followed by the vacA mutant (19/28). No ulcer was found in the gerbils infected with the cagE mutant (0/27) or in controls (0/27). Intestinal metaplasia was also found in the gerbils infected with the wild-type (14/23) or vacA mutant (15/28). Gastric cancer developed in one gerbil with wild-type infection and in one with vacA mutant infection. In conclusion, the knocking out of the cagE gene deprived wild-type H. pylori of the pathogenicity for gastritis and gastric ulcer, suggesting that the secretion system encoded by cag pathogenicity island genes plays an essential role.

A comprehensive review of the natural history of Helicobacter pylori infection in children

Across populations of children, Helicobacter pylori prevalence ranges from under 10% to over 80%. Low prevalence occurs in the U.S., Canada, and northern and western Europe; high prevalence occurs in India, Africa, Latin America, and eastern Europe. Risk factors include socioeconomic status, household crowding, ethnicity, migration from high prevalence regions, and infection status of family members. H. pylori infection is not associated with specific symptoms in children; however, it is consistently associated with antral gastritis, although its clinical significance is unclear. Duodenal ulcers associated with H. pylori are seldom seen in children under 10 years of age. H. pylori-infected children demonstrate a chronic, macrophagic, and monocytic inflammatory cell infiltrate and a lack of neutrophils, as compared with the response observed in adults. The effect of H. pylori infection on acid secretion in children remains poorly defined. The events that occur during H. pylori colonization in children should be studied more thoroughly and should include urease activity, motility, chemotaxis, adherence, and downregulation of the host response. The importance of virulence determinants described as relevant for disease during H. pylori infection has not been extensively studied in children. Highly sensitive and specific methods for the detection of H. pylori in children are needed, especially in younger pediatric populations in which colonization is in its early phases. Criteria for the use of eradication treatment in H. pylori-infected children need to be established. Multicenter pediatric studies should focus on the identification of risk factors, which can be used as prognostic indicators for the development of gastroduodenal disease later in life.