Prevalence and determinants of Helicobacter pylori infection in preschool children: a population-based study from Germany

Branching enzyme (BE) belongs to the amylolytic family which contains four highly conserved regions. These regions are proposed to play an important role in catalysis as they are thought to be necessary for catalysis and/or binding the substrate. Only one arginine residue was found to be conserved in a catalytic center at the same position in all known sequences of BEs from various species as well as in the alpha-amylase enzyme family. In mBEII, a conserved Arg residue 384 is in catalytic region 2. We have used site-directed mutagenesis of the Arg-384 residue in order to study its possible role in BE. Previous chemical modification studies (H. Cao and J. Preiss, 1996, J. Prot. Chem. 15, 291-304) suggest that it may play a role in substrate binding. Replacement of Arg-384 by Ala, Ser, Gln, and Glu in the active site caused almost total inactivation. However, a conservative mutation of the conserved Arg-384 by Lys resulted in some residual activity, approximately 5% of the wild-type enzyme. The kinetics of the purified mutant R384K enzyme were investigated and no large effect on the Km of the substrate amylose for BE was observed. Thus, these results suggest that conserved Arg residue 384 in mBEII plays an important role in the catalytic function of BEs but may not be directly involved in substrate binding.     

Helicobacter pylori infection in children

BACKGROUND: Although immigrants to the United States are usually ethnic minorities and socioeconomically disadvantaged, foreign-born women generally have lower rates of low birth weight infants than do US-born women. OBJECTIVE: To measure the relationship between maternal birthplace, ethnicity, and low birth weight infants. DESIGN: Retrospective cohort study of birth certificate data. SETTING: California, 1992. SUBJECTS: Singleton infants (n = 497 868) born to Asian, black, Latina, and white women. MAIN OUTCOME MEASURES: Very low birth weight (500-1499 g), moderately low birth weight (1500-2499 g), and normal birth weight (2500-4000 g, reference category). RESULTS: Foreign-born Latina women generally had less favorable maternal characteristics than US-born Latinas, yet foreign-born Latina women were less likely to have moderately low birth weight infants (odds ratio, 0.91; 95% confidence interval, 0.86-0.96) than US-born Latinas after adjusting for maternal age, education, marital status, parity, tobacco use, use of prenatal care, and gestational age. While foreign-born Asian women generally had a less favorable profile of maternal characteristics than US-born Asians, there was no statistically significant difference in the odds of very low birth weight or moderately low birth weight infants between foreign- and US-born Asian women. Foreign-born black women had more favorable maternal characteristics than US-born women, but there was no significant nativity difference in very low birth weight or moderately low birth weight between foreign- and US-born black women after adjusting for maternal and infant factors. CONCLUSIONS: The relationship between maternal birthplace and low birth weight varies by ethnicity. Further study is needed to understand the favorable pregnancy outcomes of foreign-born Latina women.     

Helicobacter pylori among preschool children and their parents: evidence of parent-child transmission

This study assessed the role of parental infection status in the transmission of Helicobacter pylori infection in a large population-based sample of preschool-aged children. The subjects, who lived in Ulm, Germany, and in two nearby communities, were screened for school fitness between January and July 1997. Their H. pylori infection status was determined by 13C-urea breath test. Of 1522 eligible children, 1221 (80.2%) participated in the study. Crude prevalence of H. pylori infection in children was 11.3% (95% confidence interval [CI], 9.5-13.3) and 36.4% in their parents (95% CI, 33.5-39.4). The crude odds ratio (OR) for H. pylori infection of children whose mothers were infected was 16.5 (95% CI, 8.9-30.8) and 7.9 after adjustment for potential confounders (95% CI, 4.0-15.7). The crude OR if the child's father was infected was 7.8 (95% CI, 2. 5-24.2) and 3.8 after adjustment for potential confounders (except maternal infection) (95% CI, 0.8-19.1). The results suggest that infected parents, especially infected mothers, may have a key role in transmission of H. pylori within families.     

Nodular antritis and Helicobacter pylori infection in children

We have studied 115 patients infected with Helicobacter pylori (HP). Endoscopic nodular antritis and histologic lymphonodular hyperplasia was noted. The frequency of nodular antritis was compared between the 115 HP patients and a HP-negative age-matched control group. Nodular antritis was observed in 70.4% of the HP-positive patients and 11.3% of the HP-negative group (p <0.001). The specificity of nodular antritis was 86.1%. A significant association was found between the existence of nodular antritis and histologic lymphonodular hyperplasia (67.9%; p < 0.001). In conclusion, the endoscopic nodular antritis is a frequent and specific finding in children with HP infection and is associated with histologic lymphonodular hyperplasia.     

Prevalence of Helicobacter pylori infection in asymptomatic children

OBJECTIVE: To determine the prevalence of Helicobacter pylori infection in a sample of asymptomatic Australian children. METHODOLOGY: A prospective observational study, during a 3 month period, of consecutive children aged 0 to 14 years undergoing minor elective surgical procedures in a Day Surgical Unit at a Melbourne paediatric hospital. Subjects without gastrointestinal symptoms or a family history of peptic ulcers had sociodemographic data recorded and serum collected. Serum anti-H. pylori immunoglobulin G antibodies were measured by an enzyme immunoabsorbent assay previously validated in children from the same population. RESULTS: H. pylori antibodies were present in 21/147 (14.3%) children aged 3 months to 14 years. Prevalence was not influenced by age or sex, but was greatest in children whose parents migrated from developing nations and lowest in children with Caucasian Australian or Western European parents (25.8 vs 5.9%; P < 0.001). An inverse relationship between social class and infection was also observed (P = 0.02). Multivariate analysis demonstrated the father's ethnic background as the only significant independent risk factor for H. pylori infection (P = 0.002). CONCLUSIONS: Although seroprevalence of H. pylori appears to be lower in Australian children than in developing countries there are some ethnic groups at substantially greater risk for the acquisition of H. pylori infection and its complications.     

Nutritional factors and Helicobacter pylori infection in Colombian children

The reliability (internal consistency and alternate form) of the trait version of the Positive and Negative Mood Scales in referred samples was found to be high, and the concurrent and discriminate validity was found to be moderate. As expected, means of the Positive Mood Scales were significantly higher in nonreferred samples and means of the Negative Mood Scales were significantly higher in referred samples. The alternate forms for each scale were equivalent. The Positive and Negative Mood Scales seem to be ready for use in research.     

Use caution with serologic testing for Helicobacter pylori infection in children

Commercial serologic assays accurately detect adult Helicobacter pylori infection. Their use in children remains controversial. An ELISA to detect H. pylori IgG in children was developed and compared with three commercial assays. ELISA standardization was done with sera from all ages and validation was done with another cohort of sera with known H. pylori status. Three commercial serologic assays were subsequently compared against this pediatric ELISA at independent sites, at which 142 pediatric serum samples from different countries were evaluated. The pediatric ELISA was 91.4% sensitive. Assay 3 demonstrated a sensitivity of 78%. Less sensitivity was observed for assay 1 (70%) and assay 2 (63%). Accuracy of commercial assays was greatly reduced when sera from developing countries and younger ages were evaluated. Results of serologic tests used to diagnose H. pylori should be interpreted with caution when evaluating children with abdominal pain. Accurate serologic assays in children may be more important for epidemiologic research than for clinical decision making.     

Helicobacter pylori infection and duodenal ulcer in children and adolescents

To investigate the relationship between H. pylori infection and duodenal ulcer in children and adolescents, the markers of H. pylori infection were studied in 22 children and adolescents who had duodenal ulcers and were followed prospectively (Group A). Another 36 patients with gastrointestinal symptoms, but without ulcer, were also studied for comparison (Group B). Antral and duodenal tissues were biopsied and analyzed for the presence of H. pylori using three standard methods: urease test, culture and histology. The specific IgG antibody against H. pylori positivity using the ELISA method were also analysed. By these three methods, H. pylori positivity in the antral tissues, chronic active antral gastritis, and seroprevalence rate were found to be much higher in Group A than Group B. However, a similar trend was not found in the duodenal tissues. H. pylori was found in four of five patients during postoperative follow-up for duodenal ulcer. Among the four patients, no duodenal ulcer but chronic active gastritis was detected endoscopically in three who received vagotomy. Only the one who received simple closure of the perforated duodenal ulcer had a recurrent duodenal ulcer. It was concluded that a close relationship among duodenal ulcer, chronic active gastritis and H. pylori is present in children and adolescents.     

Helicobacter pylori infection and socioeconomic factors among adult Danes

The aim of this study was to examine the relationship between housing conditions, educational level, occupational factors, and serologically diagnosed acute and chronic Helicobacter pylori infection. IgG, IgM, and IgA antibodies against Helicobacter pylori were measured by ELISA techniques in sera obtained from a random sample of 3589 Danes participating in a population study. Poor social status (odds ratio 2.2 [1.7-3.0]), short duration of schooling (odds ratio 2.0 [1.3-2.5]), lack of vocational training/education (odds ratio 1.4 [1.2-1.7]), unskilled work (odds ratio 1.7 [1.2-2.5]), and high work-related energy expenditure (odds ratio 1.4 [1.1-1.9]) increased the likelihood of chronic Helicobacter pylori infection. Chronic Helicobacter pylori infection was frequently found in people with a history of living abroad. Increased levels solely of IgM antibodies to H. pylori, interpreted as a sign of acute infection, were found more often in people who were divorced (odds ratio 2.3 [1.2-4.4]) or unmarried (odds ratio 2.0 [1.1-3.8]) and in people who worked long hours (odds ratio 2.0 [1.1-4.0]). In conclusion, educational and occupational factors relate to the likelihood of chronic Helicobacter pylori infection in adults. The rate of acute Helicobacter pylori infection is probably increased in single adults.     

Helicobacter pylori infection

CHROMagar, a chromogenic differential culture medium, is claimed to facilitate the isolation and presumptive identification of certain clinically important yeast species, e.g., Candida albicans. This study evaluated the cost-effectiveness and time advantage of using it in comparison with Sabouraud dextrose agar (SDA). Three possible pathways, each of which included the use of one or both media, were compared in a routine laboratory. A total of 21 yeast isolates was cultured from 298 clinical samples from neutropenic and AIDS patients. An overall sensitivity of 95.2% was observed for each medium and primary isolation on CHROMagar was found to be 100% sensitive and 100% specific for C. albicans. For identification purposes, after initial culture the use of CHROMagar provided the most economical and least time-consuming method. Direct inoculation on to CHROMagar is recommended for blood cultures when yeast cells are seen on microscopy and where early appropriate therapy is imperative.     

Helicobacter pylori infection in children with abdominal ailments in a developing country

Retrospective maternal report of fetal activity level was compared with developmental diagnosis in 608 consecutively referred children. Maternal history of fetal activity level was also obtained from 140 unmatched well children in a general pediatric clinic. Fetal hyperactivity was positively associated with a diagnosis of child hyperactivity, and fetal hypoactivity was positively associated with a diagnosis of mental retardation in the children. Maternal histories of fetal activity level in the control group weakened the strength of the association between fetal hyperactivity and child hyperactivity but did not affect the association between fetal hypoactivity and mental retardation in children.     

Helicobacter pylori in children

Helicobacter pylori is the major cause of antral gastritis in children, however, it is not always associated with symptoms. The exception to this occurs in duodenal ulcer disease with which H. pylori is linked in children albeit less strongly than in adults. Duodenal ulcers do not recur in older children following eradication of H. pylori. The importance of asymptomatic carriage of H. pylori in children, particularly in relation to the duration of this infection and the subsequent development of gastric cancer, remain to be established. Helicobacter pylori is associated with both hypochlorhydria and persistent diarrhoea in children in developing countries, but the significance of this association is still unknown. Although there is no consensus on the optimal regimen for treating H. pylori infection in children, dual therapy with amoxycillin and bismuth subcitrate for 2 weeks followed by monotherapy with bismuth subcitrate for a further 6 weeks will eradicate H. pylori infection in the majority of children. Those who relapse may be treated with a repeat course plus metronidazole for 4 weeks. Compliance with such regimens is a problem and shorter treatment courses that are equally effective in children need to be defined. Similarly, studies are required on the influence of the intrafamilial reservoir of H. pylori infection on relapse after treatment and the need for whole family eradication therapy.     

Positive association between Helicobacter pylori infection and food allergy in children

BACKGROUND: In children Helicobacter pylori has been involved as a pathogenetic factor in gastritis and duodenal ulcer and as a cofactor in protein-losing enteropathy, chronic diarrhoea, short stature, and gastritis lymphoproliferative disease. A subset of an H. pylori strain possesses an antigen, CagA, as a virulence factor. In the present study we determined anti-H. pylori IgG and anti-CagA IgG titres in children with food allergy. METHODS: Ninety paediatric patients were studied: 30 with food allergy, 30 with atopic asthma, and 30 with inflammatory bowel disease. Anti-H. pylori IgG and anti-CagA IgG were determined in all children by means of a commercial enzyme immunoassay (ELISA). RESULTS: The anti-H. pylori IgG titre was significantly higher in allergic patients than in the other two groups. The anti-CagA IgG titre did not differ significantly between the patients. CONCLUSIONS: These findings show a positive association between H. pylori infection and food allergy in children. We hypothesize that virulence factors other than CagA may be involved in the pathogenesis of H. pylori infection in paediatric patients with food allergy.     

Helicobacter pylori infection in the etiopathogenesis of duodenal ulcer in children

The study evaluates the frequency of Helicobacter pylori (H. pylori) infection, as well as systemic cellular immune response to H. pylori in children with duodenal ulcer (DU). The study group comprised 47 children with DU, aged 6-17 (mean 13, 1 +/- 4, 2). H. pylori detection was based on urease test, histology, culture and serologic tests. Endoscopic and morphologic findings were analysed according to Sydney System criteria. In 12 children from the overmentioned group subsets of blood lymphocytes B and T (CD3, CD4, CD8, CD3/DR, CD19) and NK cells, some neutrophils functions (phagocytosis, chemiluminescence) and phagocytes receptors before and one month after H. pylori triple treatment were investigated. H. pylori infection was detected in 44 of the investigated children. In addition, pathologic examination revealed chronic gastritis in 44 children and chronic duodenitis in 42 of them. In immunosystemic examination decreased percentage of CD8 lymphocytes and NK cells, increased CD4/CD8 ratio, decreased mitogen-induced response and changes of function and receptor expression of neutrophils were found. After H. pylori treatment in follow-up endoscopy no ulcers were found and histologic examination did not reveal chronic active gastroduodenitis, while the rate of nonactive gastritis was increased. Eradication of H. pylori infection in 41 children and normalisation of immune parameters in 11 children were obtained. The results of our investigation indicate, that H. pylori infection plays an important role in the pathogenesis of DU in children.     

Salivary immunoglobulin G assay to diagnose Helicobacter pylori infection in children

An in-house enzyme-linked immunosorbent assay (ELISA) for measurement of Helicobacter pylori-specific immunoglobulin G (IgG) and IgA in saliva was evaluated by comparison with histopathologic (Giemsa staining) and biochemical (urease quick test) examination of gastric biopsy specimens obtained from 112 children referred for diagnostic gastroscopy. Serum H. pylori IgG was also measured in a subgroup of 50 children by the same ELISA. Salivary H. pylori IgG levels were significantly higher in H. pylori-positive (n = 57) than in H. pylori-negative (n = 55) children (P < 0.001). The sensitivity and specificity of the salivary IgG test were 93 and 82%, respectively; the positive and negative predictive values were 84 and 92%, respectively; and the accuracy was 87.5%. Salivary H. pylori IgA did not distinguish H. pylori-positive from H. pylori-negative children. The performance of serum H. pylori IgG was slightly (3 to 6%) better than that of salivary H. pylori IgG. The salivary IgG test can be considered a useful tool for the screening of H. pylori infection in children.     

Clinical aspects of infection with Helicobacter pylori

About 90% of patients with duodenal ulcer and 65% of those with gastric ulcer are infected with Helicobacter pylori. H. pylori infection can be diagnosed by examination of biopsy material obtained at endoscopy; by 14C or 13C-urea breath tests, or by serological means. The relapse rate of duodenal and gastric ulcers can be considerably reduced if the bacteria are eradicated. Some of the current treatment regimens are discussed.     

Vaccine development against infection with Helicobacter pylori

Infection with Helicobacter pylori, is one of the most prevalent infections world-wide, where approximately 50% of adults in the developed world and over 90% of inhabitants in the developing world are infected. Chronic infection with H. pylori is the cause of gastritis, peptic ulcer disease and is a risk factor for gastric adenocarcinoma. Recent studies have demonstrated the suitability of an immunization strategy in the prevention and treatment of H. pylori infection, and the potential for management of disease. Mucosal administration of purified recombinant sub-unit proteins of H. pylori, together with a mucosal adjuvant, has identified urease to be highly efficacious in prophylactic and therapeutic animal model studies, and show partial therapeutic activity in humans. Several other antigens are also effective, and the recent sequencing of the H. pylori genome has led to an intensive effort in antigen discovery. Other research has centered on the identification of novel approaches for delivery, and the immunological mechanisms underlying protective immunity. In this review, preclinical data and the results of early-stage clinical trials and directions for future research on Helicobacter vaccines are described.