Detection rate of Helicobacter pylori stool antigen in newborn infants and small children

Intracellular presence and genetic relationship of Helicobacter pylori within neonates' fecal yeasts and their mothers' vaginal yeasts

Helicobacter pylori are transmissible from person to person and among family members. Mother-to-child transmission is the main intrafamilial route of H. pylori transmission. However, how it transmits from mother to child is still being determined. Vaginal yeast often transmits to neonates during delivery. Therefore, H. pylori hosted in yeast might follow the same transmission route. This study aimed to detect intracellular H. pylori in vaginal and fecal yeasts isolates and explore the role of yeast in H. pylori transmission. Yeast was isolated from the mothers' vaginal discharge and neonates' feces and identified by internal transcribed spacer (ITS) sequencing. H. pylori 16S rRNA and antigen were detected in yeast isolates by polymerase chain reaction and direct immunofluorescence assay. Genetic relationships of Candida strains isolated from seven mothers and their corresponding neonates were determined by random amplified polymorphic DNA (RAPD) fingerprinting and ITS alignment. The Candida isolates from four mother-neonate pairs had identical RAPD patterns and highly homologous ITS sequences. The current study showed H. pylori could be sheltered within yeast colonizing the vagina, and fecal yeast from neonates is genetically related to the vaginal yeast from their mothers. Thus, vaginal yeast presents a potential reservoir of H. pylori and plays a vital role in the transmission from mother to neonate.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Helicobacter pylori infection in Icelandic children

OBJECTIVE

The prevalence of Helicobacter pylori (HP) infection is decreasing in the western world. The seroprevalence among 25-50-year-old Icelandic adults was recently shown to be 30-40%. Information on the seroprevalence in Nordic children is limited. We aimed at ascertaining the infection prevalence among healthy Icelandic children.

METHODS

The infection status in stored frozen blood samples from two cross-sectional studies on the health of 7-9-year-old children (n = 125) and 16-18-year-old adolescents (n = 80) was determined by enzyme-linked immunosorbent assay (ELISA). Information on family demographics and GI symptoms was obtained by standardized questionnaires.

RESULTS

Overall, 3.4% (7/205) of the children were infected with H. pylori. The prevalence was 2.6% (5/190), missing data n = 3, among children with both parents born in a low prevalence country compared to 17% (2/12) among those with at least one parent born in a high prevalence area (p = .026). When at least one parent was born in a high prevalence country, the odds ratio for being H. pylori seropositive was 2.2 (95% CI, 1.02-54.67), when adjusted for the educational status of the mother. There was no significant association between H. pylori infection and gastrointestinal symptoms.

CONCLUSION

Prevalence of H. pylori infection in Iceland has become very low, suggesting a great reduction in transmission from older generations. There was an association between H. pylori infection and origin from high prevalence areas but not with gastrointestinal symptoms. The results mirror recent studies of children of Scandinavian ancestry.

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.

[Maternal infection due to Helicobacter pylori does not increase the risk of the infection in the first trimester of the life of their infants]

INTRODUCTION

H. pylori infection is acquired early in childhood. However, there is little information available regarding the role of breastfeeding and neonatal acquisition of the infection.

OBJECTIVE

To evaluate factors affecting the acquisition of H. pylori in newborns and infants from infected mothers.

PATIENTS AND METHOD

Consecutive mothers and their newborns were recruited into the study from the maternity unit, immediately after delivery. After signing informed consent, one stool sample from the mother was obtained before hospital discharge. Three stool samples of the newborns were then collected at home at 15, 60, and 90 days of life, for the detection of H. pylori antigen (Monoclonal HpSAg, sensitivity 94% and specificity 97%). The socio-epidemiological and biomedical variables were also analysed using a questionnaire.

RESULTS

A total of 32 mother-child pairs (64 subjects) were enrolled. The mean maternal age was 30.1±5.1 years, with 53% vaginal delivery, and 85% exclusively breastfed. There were 13 (40%) infected mothers. No H. pylori infection was detected in newborns and infants up to 3 months of follow-up. No significant differences were found in socioeconomic level between infected versus non-infected mothers (both groups mostly in the very high socioeconomic category: 28% and 32%, respectively, P=.15) and in the number of family members between infected versus non-infected mothers (3.8±0.8 vs 4.2±1.8 persons, P=.18).

CONCLUSION

Despite having a significant percentage of H. pylori-infected mothers, no newborn was infected at the third month of life. The protective role of breastfeeding cannot be ruled out.

Why are East Asians more susceptible to several infection-associated cancers (carcinomas of the nasopharynx, stomach, liver, adenocarcinoma of the lung, nasal NK/T-cell lymphomas)?

There are at least five cancers with uniquely high incidence amongst East and Southeast Asian ethnic groups - namely nasopharyngeal carcinoma (NPC); gastric carcinoma; hepatocellular carcinoma (HCC); adeno-carcinoma of the lung in female non-smokers and nasal NK/T-cell lymphomas. They all appear to be related to an infective cause (Epstein Barr Virus, Helicobacter pylori, hepatitis B virus). We hypothesize that a genetic bottleneck 30,000years ago at the Last Glacial Maximum could have resulted in unique genetic polymorphisms in Toll-like receptor 8, making East Asians more vulnerable to these infective associated cancers. This bottleneck could have been caused by the presence of malaria in the southern Himalayan conduit between central and East Asia; and only those with an attenuated innate immune response to the malarial parasite (perhaps reflected by the TLR8 polymorphism) were spared the ravages of cerebral malaria; allowing these people to cross into east Asia, but then rendering them susceptible to later endemic infections and their associated cancers.

Does bloody aspirate reflect the state of upper gastrointestinal mucosa in a critically ill newborn?

BACKGROUND AND STUDY AIMS

Critically ill newborns have many risk factors to develop stress related mucosal lesions (SRML). We used upper endoscopy to evaluate the presence of SRML in these neonates, to know the specificity and sensitivity of the bloody gastric aspirate to detect SRML and to identify the risk factors associated with the presence of SRML and bloody gastric aspirate.

PATIENTS AND METHODS

This is a cross-sectional study done on 100 critically ill newborn after becoming clinically stable. SRML were diagnosed if there is hyperaemia, erosions or ulcers in the oesophagus, stomach, and/or the duodenum.

RESULTS

SRML were found in 77% of neonates in the NICU though frank bloody aspirate was detected in only 22% of neonates. The presence of bloody aspirate showed low sensitivity (24.68%) and high specificity (86.96%) for the presence of SRML. The presence of bloody gastric aspirate showed a double fold risk for the presence SRML (OR=2.184, CI=0.584-8.171). Factors associated with SRML included respiratory distress (p=0.000, risk=4.006), the use of nasogastric tube (p=0.017, OR=3.281) and the use of triple antibiotics (p=0.001, risk=1.432). Factors associated with the presence of bloody gastric aspirate included the use of nasogastric tube (OR=1.629, p=0.000) and the presence of haemostatic disorders (OR=3.143, p=0.039). It was also associated with lower haemoglobin levels (p=0.000).

CONCLUSION

SRML represents an under-diagnosed problem in NICUs. Absence of bloody gastric aspirate does not exclude the presence of SRML.

Non-invasive genotyping of Helicobacter pylori cagA, vacA, and hopQ from asymptomatic children

BACKGROUND

Helicobacter pylori infection is usually acquired in childhood, but little is known about its natural history in asymptomatic children, primarily due to the paucity of non-invasive diagnostic methods. H. pylori strains harboring cagA and specific alleles of hopQ and vacA are associated with increased risk for gastric cancer. Many studies of H. pylori virulence markers in children have the bias that symptomatic subjects are selected for endoscopy, and these children may harbor the most virulent strains. Our aim is to genotype cagA, hopQ, and vacA alleles in stool DNA samples of healthy Colombian children residing in an area with high incidence of gastric cancer, to avoid selection bias resulting from endoscopy.

METHODS

H. pylori status of 86 asymptomatic children was assessed by (13) C-urea breath test (UBT) and PCR. H. pylori 16S rRNA, cagA, hopQ, and vacA genes were amplified from stool DNA samples and sequenced.

RESULTS

UBT was positive in 69 (80.2%) of 86 children; in stool DNA analysis, 78.3% were positive by 16S rRNA PCR. cagA, vacA, and hopQ were detected in 66.1%, 84.6%, and 72.3% of stool DNA samples from 16S rRNA-positive children. Of the children's DNA samples, which revealed vacA and hopQ alleles, 91.7% showed vacA s1 and 73.7% showed type I hopQ. Type I hopQ alleles were associated with cagA positivity and vacA s1 genotypes (p < 0.0001).

CONCLUSIONS

Using stool DNA samples, virulence markers of H. pylori were successfully genotyped in a high percentage of the asymptomatic infected children, revealing a high prevalence of genotypes associated with virulence. Type I hopQ alleles were associated with the presence of cagA and the vacA s1 genotype.

Helicobacter pylori in apparently healthy children aged 0-12 years in urban Kampala, Uganda: a community-based cross sectional survey

Background

Helicobacter pylori is one of the most common causes of bacterial infection in human beings. Studies have showed a high prevalence of Helicobacter pylori among people in low-income countries and colonization early in life. A monoclonal antigen test, performed on faeces, HpSA^®ImmunoCardSTAT, has a high sensitivity, specificity and accuracy and the faecal test can be performed in all ages, also in resource-limited settings. The main objective of this study was to determine the prevalence and factors associated with Helicobacter pylori colonization in apparently healthy children aged 0-12 years in urban Kampala, Uganda.

Method

We tested 427 apparently healthy children, age 0-12 years (211 males, 216 females), in a cross sectional survey for Helicobacter pylori colonization using HpSA ^®ImmunoCardSTAT. A short standardized interview with socio-demographic information and medical history was used to assess risk factors.

Results

The overall prevalence of Helicobacter pylori in the 427 children was 44.3% (189 out of 427). Early colonization was common, 28.7%, in children younger than 1 year of age. The age specific rates were 46.0% in children age 1- < 3 years, 51.7% in children age 3- < 6 years, 54.8% in children age 6- < 9 years and 40.0% in children age 9- < 12 years. There was a significant difference in prevalence by gender; female 38.5% versus male 49.8% and by type of housing; permanent house 38.5% versus semi-permanent house 48.6%. Congestive living and education level of the female caretaker showed a clear trend for a difference in prevalence. Factors independently associated with Helicobacter pylori colonization included: drugs taken last three months, using a pit latrine, sources of drinking water and wealth index.

Conclusion

The prevalence of Helicobacter pylori colonization among urban Ugandan children is high at an early age and increases with age. The impact of Helicobacter pylori colonization on children's health in Uganda needs to be further clarified.

The source of Helicobacter pylori infection in the neonatal period

AIMS

To investigate the transmission of Helicobacter pylori in the perinatal period.

METHODS

H. pylori status of 180 women was preliminarily screened by serology and stool antigen test (SAT) within the fourth day after delivery and a positive value was confirmed by (13)C-urea breath test. Infants were analyzed by SAT at 1, 6, 12 and 18 months of age. H. pylori status was also investigated in the medical and paramedical staff of the Neonatology Unit.

RESULTS

H. pylori infection was found in 34.4% of the women. At the 1(st) month of age, 5 out of 172 newborns (2.9%) were H. pylori positive by SAT. Three out of the five positive infants were born to H. pylori non-infected mothers. Formula feeding (P=0.02) and admission in intermediate-risk neonatal unit (P=0.01) were significantly related to a positive H. pylori result. Medical and paramedical staff of the neonatology unit was found H. pylori positive in 34.8% of cases. All five H. pylori positive children spontaneously cleared the infection.

CONCLUSIONS

Perinatal H. pylori SAT positive status is low in our area, and it may be found both in infants from infected or non-infected mothers. Formula feeding and admission in intermediate-risk neonatal unit appear to be related with H. pylori infection.

Epidemiology of Helicobacter pylori infection in asymptomatic children: a prospective population-based study from the Czech Republic. Application of a monoclonal-based antigen-in-stool enzyme immunoassay

BACKGROUND

Acquisition of Helicobacter pylori occurs mainly in childhood and is significantly influenced by geographical variations. The aim of this study is to evaluate the prevalence of H. pylori infection in a population-based sample of asymptomatic children in the Czech Republic. Furthermore, this study aims to identify potential risk factors associated with this infection.

MATERIALS AND METHODS

A prospective, cross-sectional, population-based study was undertaken in 1545 asymptomatic Czech children (aged 0-15 years; male 49.3%). Active H. pylori infection was diagnosed by monoclonal antibody-based antigen-in-stool enzyme immunoassay. Socio-demographic details of each subject were analyzed using a self-administered standardized questionnaire. Multiple regression analysis was performed.

RESULTS

Overall, 7.1% of asymptomatic children were diagnosed with H. pylori infection. Of the infected children, 5.8% lived in the general population. A positive association was found with increasing age, although not with gender. Independent risk factors associated with H. pylori infection in our pediatric population were: the number of children in a household (odds ratio [OR] 4.26; confidence interval [CI] 1.91-9.80); lack of formal education of fathers (OR 0.23; CI 0.18-0.64) and institutionalized children (OR 6.33; CI 2.25-26.50).

CONCLUSIONS

This study of a large cohort of children demonstrated that, independent of gender, H. pylori infection in the Czech Republic is among the lowest reported in Europe. Socioeconomically disadvantaged children, unfortunately, are still at risk of harboring this potentially preventable infection in this low-prevalence region.

Helicobacter pylori antigen in stool is associated with SIDS and sudden infant deaths due to infectious disease

Infection with Helicobacter pylori has been proposed to be a common cause of Sudden Infant Death Syndrome (SIDS). We investigated the frequency of H. pylori infection in 160 infant deaths and 156 live controls by means of the Helicobacter pylori stool antigen (HpSA) immunoassay. Histology was performed in 26 randomly selected cases. H. pylori antigen was detected in 8% (12/156) of the live controls compared with 25% (30/122) of SIDS cases (p < 0.001), 53% (9/17) of deaths due to infection (p < 0.001), and 9% (1/11) of accidental/violent deaths (p = 0.60). In the classic age peak for SIDS, 1-5 mo, 31% (21/67) of SIDS cases were HpSA positive compared with 1.5% (1/68) of live controls (p < 0.001). Rod-like immunoperoxidase positive H. pylori organisms were identified in 7/12 HpSA positive gastric antrum sections compared with 2/14 HpSA negative (p = 0.038). Significantly elevated IL-6 levels in cerebrospinal fluid representing signs of central immune stimulation were demonstrated in HpSA positive SIDS victims compared with HpSA negative victims (p = 0.045). Detection of H. pylori antigen in stool is associated with SIDS and deaths due to infections. We hypothesize that H. pylori infection in infancy may be involved as the triggering pathogen for sudden death during the first 5 month after birth.

Helicobacter pylori infection in pediatrics

During the last year, epidemiologic studies have shown that spontaneous clearance of Helicobacter pylori infection has a less significant role in countries with high prevalence and, in contrast to adults, there is no male predominance of H. pylori infection in children. Early acquisition of H. pylori may play a role in the development of recurrent abdominal pain in children less than 5 years of age. In this very young age group, the adequate performance of stool antigen test and (13)C urea-breath test demonstrated satisfactory sensitivity and specificity as non-invasive methods to diagnose H. pylori infection. In the current paper, the most relevant pediatric studies on H. pylori infection published between April 2006 and March 2007 are reviewed.