Helicobacter pylori stool antigen (HpSA) tests in children before and after eradication therapy: comparison of rapid immunochromatographic assay and HpSA ELISA

Rapid, Economical Detection of Helicobacter pylori Using Gold Colloidal Nanoparticle Biosensors

Nucleic acid tests (NAT), the gold standard diagnostic technology, play a crucial role in the prevention of infectious diseases. However, PCR, the current state-of-the-art NAT, is expensive, slow, and requires dedicated infrastructure and facilities. Therefore, there exists an urgent need to create alternative molecular diagnostic technologies. We describe the use of a gold colloidal nanobiosensor detection system that can specifically and sensitively detect the 16S rRNA gene of the worldwide gastric pathogen Helicobacter pylori. We demonstrate the systematic identification of oligonucleotide probe sequences according to secondary structure, binding energy, and homology search criteria. We selected three probe sequences that were used to evaluate the detection of a 120 nt synthetic analyte. Detection of this analyte resulted in a visual color change in the solution to a limit of detection (LOD) of 10 nM and by spectrophotometric means to 1 nM. Furthermore, we demonstrated that the system could detect clinical samples of H. pylori with a LOD of 5 × 105 copies/mL. The system displayed no cross-reactivity with potentially confounding bacterial pathogens. Importantly, we also demonstrated the ability of the detection system to detect clinical samples of H. pyloriwithout the requirement of a separate DNA extraction, allowing for a one-step detection system. In summary, we have created a simple-to-use, economical, rapid, sensitive, and specific alternative to PCR that could be useful in resource-limited settings to control the spread of infectious diseases.

A comparative systematic review and meta-analysis on the diagnostic accuracy of non-invasive tests for Helicobacter pylori detection in elderly patients

Background

Helicobacter pylori (H. pylori) infection, a type I carcinogen, affects approximately 50% of the global population, correlating with various gastric pathologies. Notably, diagnostic sensitivities of non-invasive methods, such as the stool antigen test (HpSA), Serology, and Urea Breath Test (UBT), have been suggested to be less effective in older age groups. This study systematically reviews and meta-analyzes the diagnostic accuracy of these tests within the elderly population.

Methods

A comprehensive literature search was performed across multiple databases, including PubMed, Medline, and Web of Science, up to July 2023. Data were pooled and analyzed using random-effects models. Sensitivity, specificity, and Diagnostic Odds Ratios (DOR) were computed for the tests. Heterogeneity and risk of bias were assessed.

Results

Eight studies involving diverse geographic locations and totaling between 46 and 1,441 participants per study were included. The pooled sensitivity and specificity for HpSA were 72.5 and 94.7%, for Serology 83.7 and 73.3%, and for UBT 96.4 and 88.3%, respectively. DOR for UBT, HpSA, and Serology were 94.5, 47.9, and 14.2, respectively. High levels of heterogeneity were observed across the studies.

Conclusion

UBT and HpSA proved effective for diagnosing H. pylori in those over 60, while serology showed lower specificity. Despite methodological variations in available studies, these non-invasive tests offer reliable alternatives, especially for older patients who recently undergone endoscopy or without an indication for it, warranting consideration by healthcare practitioners.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.

Evaluation of the diagnostic performance and the utility of Helicobacter pylori stool antigen lateral immunochromatography assay

Background

Helicobacter pylori causes the most common human gastric infection. H. pylori Stool Antigen Lateral Flow Immunochromatography assay (HpSA-LFIA) is considered one of the most cost-effective and rapid non-invasive assays (active tests). Evaluating HpSA-LFIA is of crucial for ensuring accuracy and utility assurance. This study aimed to evaluate the polyclonal antibody-based HpSA-LFIA in comparison to a monoclonal antibody-based ELISA kit.

Methodology

Stool samples were collected from 200 gastric patients for HpSA-LFIA and semiquantitative HpSA-ELISA tests. A statistical analysis of the diagnostic performance was performed using MedCalc software. Chi-square tests were performed to determine the effects of gender and age.

Results and conclusion

The results showed that HpSA-LFIA achieved remarkable sensitivity (93.75%) and NPV (98.00%). However, it had poor specificity, PPV, and accuracy of 59.76%, 31.25%, and 65.31%, respectively. LR+ and LR-were 2.33% & 0.1%, respectively. Gender didn't affect the diagnostic performance of HpSA-LFIA. Age groups had irrelevant sensitivity; however, specificity was significantly higher in patients aged >45 years. We can conclude that HpSA-LFIA was not accurate enough to be the sole test for diagnosis and suggest developing other confirmatory tests in case of positive conditions.

Stool Antigen Testing, a Reliable Noninvasive Method of Assessment of Helicobacter pylori Infection Among Patients with Gastro-duodenal Disorders in Cameroon

BACKGROUND

Several techniques such as invasive and noninvasive are used for the diagnosis of H. pylori infection.

AIM

The aim of this study was to compare the results of rapid urease test, stool antigen test and serology in diagnosing H. pylori infection in Cameroon.

METHODS

Hundred patients (66 women and 34 men) were enrolled. Each patient gave a written consent. The study was approved by the local Ethical Committee of Medical Sciences and the institutional review board. From each patient, blood, stool and gastric biopsies samples were collected for H. pylori detection using three methods: stool antigen test, serology and rapid urease test (RUT), taken as gold standard. Statistical analysis was performed using Graph pad Prism 7.

RESULTS

Helicobacter pylori infection was detected in 43%, 45% and 73% of patients based on the RUT, stool antigen test and serology, respectively. The difference was statistically significant between serology and RUT (P = 0.0026), but not between stool antigens test and RUT (P = 0.288). Taken RUT as gold standard, the sensitivity, specificity, positive and negative predictive values of stool antigens test and serology were 65.11, 70.17, 62.22 and 72.72%; 88.37, 40.35, 55.77 and 82.14%, respectively. The accuracy of stool antigen test and serology was 68 and 61%, respectively.

CONCLUSIONS

Our finding showed that stool antigen test can be used as a noninvasive method of assessment of H. pylori infection in our setting. Serological test can be used in screening; however, further diagnostic tests need to be carried out to confirm seropositive cases.

Diagnosis of Helicobacter pylori infection in the elderly using an immunochromatographic assay-based stool antigen test

The diagnostic value of Helicobacter pylori stool antigen (HpSA) tests in elderly subjects remains unclear. The objective of this study was to assess the diagnostic accuracy of the immunochromatographic assay‐based HpSA test in a male elderly cohort and identify factors affecting the accuracy. Data for asymptomatic elderly male citizens (≥65 years old) who received health checkups at the Chinese PLA General Hospital between July 2007 and November 2018 were collected. The diagnostic accuracy of the HpSA test was determined using the ¹³C‐urea breath test as a reference standard. Associations between baseline comorbidities and the accuracy of the HpSA test were analyzed. In total, 316 participants were enrolled, including 193 in the pre‐treatment group (77.2 ± 7.8 years old) and 123 in the post‐treatment group (78.7 ± 8.3 years old). The accuracy (91.5%, 91.2%, and 91.9%) and specificity (97.6%, 98.7%, and 96.0%) were high in all participants, pre‐ and post‐treatment groups, respectively. However, sensitivities were only 68.7%, 65.1%, and 75.0%, respectively. In the pre‐treatment group, constipation was associated with decreased sensitivity (p = 0.039), while colorectal polyps were associated with increased sensitivity (p = 0.010). Multivariate analysis indicated that constipation and colorectal polyps are independent factors for the sensitivity of HpSA in the pre‐treatment group. The immunochromatographic assay‐based HpSA test achieved high accuracy with high specificity but suboptimal sensitivity in the elderly male cohort. Constipation and colorectal polyps were negatively and positively associated with HpSA sensitivity, respectively, in the pre‐treatment group.

On-chip stool liquefaction via acoustofluidics

Microfluidic-based portable devices for stool analysis are important for detecting established biomarkers for gastrointestinal disorders and understanding the relationship between gut microbiota imbalances and various health conditions, ranging from digestive disorders to neurodegenerative diseases. However, the challenge of processing stool samples in microfluidic devices hinders the development of a standalone platform. Here, we present the first microfluidic chip that can liquefy stool samples via acoustic streaming. With an acoustic transducer actively generating strong micro-vortex streaming, stool samples and buffers in microchannel can be homogenized at a flow rate up to 30 μL min-1. After homogenization, an array of 100 μm wide micropillars can further purify stool samples by filtering out large debris. A favorable biocompatibility was also demonstrated for our acoustofluidic-based stool liquefaction chip by examining bacteria morphology and viability. Moreover, stool samples with different consistencies were liquefied. Our acoustofluidic chip offers a miniaturized, robust, and biocompatible solution for stool sample preparation in a microfluidic environment and can be potentially integrated with stool analysis units for designing portable stool diagnostics platforms.

Helicobacter pylori infection in children: an overview of diagnostic methods

Children differ from adults regarding Helicobacter pylori (H. pylori) infection in many terms. H. pylori infection represents a key factor in the pathogenesis of duodenal ulcer and chronic gastritis in children. H. pylori infection causes some extraintestinal diseases as well as gastrointestinal diseases. Although, among these illnesses in children, symptoms like recurrent abdominal pain are not specific. Moreover, the role of the pathogen in the growth faltering, iron deficiency anemia, and asthma still remains controversial. A reliable method to detect H. pylori infection is a crucial issue, sand is still a matter of active debate. The tests applied for H. pylori diagnosis are grouped as either invasive or non-invasive methods. Invasive methods consist of endoscopic evaluation, the rapid urease test (RUT), histology, and bacterial culture. Non-invasive tests include the urea breath test (UBT), stool antigen test (SAT), serology, and molecular diagnostic approaches. Use of endoscopy is a pre-requisite for all invasive methods and poses difficulties in children as it is a difficult procedure and requires patient's cooperation. For this reason, the non-invasive tests have been commonly used in children, although their accuracy is not very reliable in some cases. Invasive tests may be opted to confirm the diagnosis as and when needed. This review presents the diagnostic tests used to detect H. pylori infection in children.

Non-invasive tests for the diagnosis of helicobacter pylori: state of the art

Usually, non-invasive tests are the first methods for diagnosing Helicobacter pylori (HP) infection. Among these, serological test, stool antigen research and urea breath test are the most used. Antibodies anti-HP are not recommended in low prevalence population, moreover they cannot reveal an ongoing infection, but they only prove a contact with the bacterium. Also, they can persist for a long time after the eradication of the infection, therefore, they should not be used to verify the success of eradication therapy. Stool antigen research and Urea Breath Test (UBT) are useful both in diagnosis and during follow-up after eradication treatment. The stool antigen test is cheaper than Urea breath test with similar sensitivity and specificity.  Non-invasive tests are not able to diagnose the associated complications to HP infection.

Identification of the Apa protein secreted by Mycobacterium avium subsp. paratuberculosis as a novel fecal biomarker for Johne's disease in cattle

Paratuberculosis (PTB) or Johne's disease is a chronic intestinal infection of ruminants, caused by Mycobacterium avium subsp. paratuberculosis. The shedding of mycobacteria in the feces starts at the initial stages and increases with disease progression, suggesting that antigens secreted by mycobacteria could be excreted in the feces. Previously, we demonstrated that the alanine and proline-rich antigen (Apa), a secretory antigen of Map, could be detected in the intestine of cows with PTB using a monoclonal antibody. In this study, we verified whether this protein can be found in consistently detectable levels in the feces of cattle with PTB. Feces were obtained from cows with Johne's disease confirmed by laboratory tests, cows with suspected PTB based on seropositivity and from PTB-free control cows. Samples were immunoprecipitated using anti-Apa monoclonal antibody and analyzed by immunoblot. The Apa was detected as a 60/70 kDa doublet band in all samples obtained from animals with laboratory-confirmed disease and in a substantial proportion of seropositive asymptomatic animals, but not in the control samples. Additionally, the antigen was detected in the feces of animals with Johne's disease by ELISA. This study strongly suggests that Apa is a potential fecal biomarker of Johne's disease that could serve for immunodiagnosis.

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.

Stool antigen detection versus 13C-urea breath test for non-invasive diagnosis of pediatric Helicobacter pylori infection in a limited resource setting

INTRODUCTION

The prevalence of childhood infection with Helicobacter pylori is high, especially in developing countries. Non-invasive methods for detection of infection in children should be inexpensive, easy to perform, well tolerated and have a high diagnostic accuracy. We aimed to compare the reliability, specificity and sensitivity of the H. pylori stool antigen (HpSA) test with the 13C-urea breath test (13C-UBT) for the diagnosis of H. pylori infection in a limited resource setting.

MATERIAL AND METHODS

The stool samples of 60 symptomatic and dyspeptic children with a mean age of 7.2 ±3.7 years (2-15 years) were evaluated using the rapid One step HpSA test by lateral flow immunoassay. The 13C-UBT was used as the gold standard method for the diagnosis of H. pylori infection.

RESULTS

The HpSA test detected H. pylori antigen in 34 out of 38 positive patients with 4 false-negatives (sensitivity 89.5%, 95% confidence interval (CI): 75.2-97.1%), while 21 patients had true-negative results and one false-positive (specificity 95.5%, 95% CI: 77.2-99.9%), with a strong measure of agreement between the HpSA test and the 13C-UBT (κ = 0.83, 95% CI: 68-97%, p < 0.001). It had a positive predictive value of 97.1% (95% CI: 85.1-99.9%), a negative predictive value of 84% (95% CI: 63.9-95.5%) and an accuracy of 91.7%.

CONCLUSIONS

The rapid lateral flow HpSA test is a reliable method for the primary diagnosis of H. pylori infections in children, though not as accurate as the 13C-UBT. It is more affordable, simpler to perform and more tolerable, representing a viable alternative, especially in developing countries.

Updates on the Diagnosis of Helicobacter pylori Infection in Children: What Are the Differences between Adults and Children?

Helicobacter pylori infection is acquired mainly during childhood and causes various diseases such as gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and iron deficiency anemia. Although H. pylori infection in children differs from adults in many ways, this is often overlooked in clinical practice. Unlike adults, nodular gastritis may be a pathognomonic endoscopic finding of childhood H. pylori infection. Histopathological findings of gastric tissues are also different in children due to predominance of lymphocytes and plasma cells and the formation of gastric MALT. Although endoscopy is recommended for the initial diagnosis of H. pylori infection, several non-invasive diagnostic tests such as the urea breath test (UBT) and the H. pylori stool antigen test (HpSA) are available and well validated even in children. According to recent data, both the (13)C-UBT and HpSA using enzyme-linked immunosorbent assay are reliable non-invasive tests to determine H. pylori status after eradication therapy, although children younger than 6 years are known to have high false positives. When invasive or noninvasive tests are applied to children to detect H. pylori infection, it should be noted that there are differences between children and adults in diagnosing H. pylori infection.

Performance of a one-step fecal sample-based test for diagnosis of Helicobacter pylori infection in primary care and mass screening settings

BACKGROUND/PURPOSE

An alternative screening test is needed to efficiently eradicate Helicobacter pylori from a population with prevalent upper gastrointestinal lesions. We evaluated the performance of a new one-step fecal test for H. pylori for diagnosis of H. pylori infection in Taiwan.

METHODS

We developed a fecal test to detect H. pylori based on the immunochronomatographic assay and a mixture of monoclonal antibodies. We first recruited symptomatic patients from the primary care setting to evaluate fecal test performance using a reference standard consisting of (13)C urea breath test, rapid urease test, and histology. We also compared the performance of the fecal test with that of others. Next, we recruited asymptomatic participants from the mass screening setting to evaluate population attendance for the fecal test and compared its performance with that of (13)C urea breath test.

RESULTS

In the primary care setting, 117 patients were recruited; H. pylori infection was confirmed in 58 (49.6%). Fecal test sensitivity, specificity, positive and negative predictive values, and accuracy were 88.0% [95% confidence interval (CI): 79.6-96.4%], 100%, 100%, 89.4% (95% CI, 82.0-96.8%), and 94% (95% CI, 89.7-98.3%), respectively. Fecal test specificity and positive predictive value were significantly higher than those of the serological test, whereas the sensitivity and negative predictive value were lower than those of the (13)C urea breath test (p < 0.05). In the mass screening setting, 2720 of 3520 invited individuals participated (77.3%; 95% CI, 76-78.7%); 649 (23.9%) showed positive results. Concordance rate and kappa statistic between the fecal test and (13)C urea breath test were 91.7% (563/614; 95% CI, 89.9-94.1%) and 0.78 (95% CI, 0.73-0.84), respectively.

CONCLUSION

Given the acceptable sensitivity, excellent specificity, and high participation rate to screening, the one-step H. pylori stool antigen test is feasible for wide application in the community.

Accuracy of stool antigen test for the diagnosis of Helicobacter pylori infection in children: a meta-analysis

INTRODUCTION

Helicobacter pylori (H. pylori) is regarded as a major pathogen in gastrointestinal diseases and the infection rate is still at a high level in children. Therefore, the diagnosis is of great clinical importance. The objective was to perform a meta-analysis on H. pylori stool antigen test (SAT) for the diagnosis of the infection in children.

METHODS

Published information on the sensitivity and specificity of stool antigen test in each study was collected to assess the accuracy of the test for the diagnosis of H. pylori infection. Forty-five eligible studies were selected for analysis. Data on the publication year, H. pylori prevalence, eradication rate and gold standard of each study were summarized.

RESULT

Forty-five studies, including 5931 patients, evaluated the accurancy of H. pylori SAT. Pooled sensitivity, specificity, LR+ and LR- were: 92.1%, 94.1%, 17.01, 0.085, respectively. Subgroup analyses were conducted to evaluate the sensitivity and specificity of H. pylori SAT in different situations and found that sensitivity and specificity were significantly higher when monoclonal H. pylori SAT and two or more reference methods were used.

CONCLUSIONS

Detection of H. pylori antigen in stools with ELISA monoclonal antibodies is a non-invasive efficient test for the diagnosis of infection in children. However, the available one-step and polyclonal SAT tests are still unreliable.

[Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition]

Since the Korean College of Helicobacter and Upper Gastrointestinal Research has first developed the guideline for the diagnosis and treatment of Helicobacter pylori infection in 1998, the revised guideline was proposed in 2009 by the same group. Although the revised guideline was made by comprehensive review of previous articles and consensus of authoritative expert opinions, the evidence-based developmental process was not applied in the revision of the guideline. This new guideline has been revised especially in terms of changes in the indication and treatment of H. pylori infection in Korea, and developed by the adaptation process as evidence-based method; 6 guidelines were retrieved by systematic review and the Appraisal of Guidelines for Research and Evaluation (AGREE) II process, 21 statements were made with grading system and revised by modified Delphi method. After revision, 11 statements for the indication of test and treatment, 4 statements for the diagnosis and 4 statements for the treatment have been developed, respectively. The revised guideline has been reviewed by external experts before the official endorsement, and will be disseminated for usual clinical practice in Korea. Also, the scheduled update and revision of the guideline will be made periodically.

Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition

The Korean College of Helicobacter and Upper Gastrointestinal Research first developed guidelines for the diagnosis and treatment of Helicobacter pylori (H. pylori) infection in 1998, and revised guidelines were proposed in 2009 by the same group. Although the revised guidelines were based on a comprehensive review of published articles and the consensus of expert opinions, the revised guidelines were not developed using an evidence-based process. The new guidelines presented in this study include specific changes regarding indication and treatment of H. pylori infection in Korea, and were developed through the adaptation process using an evidence-based approach. After systematic review of the literature, six guidelines were selected using the Appraisal of Guidelines for Research and Evaluation (AGREE) II process. A total of 21 statements were proposed with the grading system and revised using the modified Delphi method. After the guideline revisions, 11 statements about indication of test and treatment, four statements about diagnosis, and four statements about treatment of H. pylori infection were developed. The revised guidelines were reviewed by external experts before receiving official endorsement from the Korean College of Helicobacter and Upper Gastrointestinal Research, and disseminated to physicians and other medical professionals for use in clinical practice in Korea. The guidelines will continue to be updated and revised periodically.

Prospective evaluation of a new stool antigen test for the detection of Helicobacter pylori, in comparison with histology, rapid urease test, (13)C-urea breath test, and serology

BACKGROUND AND AIMS

This study aimed to evaluate the efficacy of a new polyclonal enzyme immunoassay for the detection of Helicobacter pylori (H. pylori) antigen in stool by determination of the optimal cut-off value in the screening population.

METHODS

A consecutive 515 patients undergoing a routine health check-up were prospectively enrolled. H. pylori infection was defined if at least two of four tests (histology, rapid urease test, (13)C-urea breath test, and serology) were positive. A stool antigen test (EZ-STEP H. pylori) was performed for the detection of H. pylori. The optimal cut-off value was determined by the receiver-operator characteristic curve. The diagnostic performance of each test was evaluated with regard to the histological diagnosis of atrophic gastritis (AG)/intestinal metaplasia (IM), degree of AG/IM, and old age.

RESULTS

Sensitivity, specificity, positive and negative predictive values, and accuracy of the stool antigen test were 93.1%, 94.6%, 95.1%, 92.3%, and 93.8%, respectively. The sensitivity of histology, rapid urease test, and the (13)C-urea breath test ranged from 89.1% to 97.6%, and their specificity was > 98%, while serology had high sensitivity, but low specificity. The accuracy of the stool antigen test was comparable to that of other methods (93.6-95.9%), whereas it was higher than that of serology. The stool antigen test still showed good diagnostic performance in the setting of progression of AG/IM and in patients over 40 years.

CONCLUSIONS

The performance of a new stool antigen test was comparable to that of other methods in the diagnosis of H. pylori infection for the screening population, even with the presence of AG/IM.

Validation of a rapid stool antigen test for diagnosis of Helicobacter pylori infection

The aim of this study was to validate the rapid lateral flow Helicobacter pylori stool antigen test (One step H. pylori antigen test, ACON laboratories, San Diego, USA; Prime diagnostics, São Paulo), using 13C-Urea Breath Test as the gold standard for H. pylori infection diagnosis. A total of 98 consecutive patients, asymptomatic or dyspeptic, entered the study. Sixty-nine were women, with a mean age of 45.76 ± 14.59 years (14 to 79 years). In the H. pylori-positive group, the rapid stool antigen test detected H. pylori antigen in 44 of the 50 positive patients (sensitivity 88%; 95% CI: 75.7-95.5%), and six false-negative; and in the H. pylori-negative group 42 presented negative results (specificity 87.5%; 95% CI: 74.7-95.3%), and six false-positive, showing a substantial agreement (Kappa Index = 0.75; p < 0.0001; 95% CI: 0.6-0.9). Forty four of fifty patients that had positive stool antigen were H. pylori-positive, the PPV of the stool antigen test was 88% (95% CI: 75.7-95.5%), and 42 patients with negative stool antigen test were H. pylori-negative, the NPV of the stool antigen test was 87.5% (95% CI: 74.7-95.3%). We conclude that the lateral flow stool antigen test can be used as an alternative to breath test for H. pylori infection diagnosis especially in developing countries.

Upper gastrointestinal bleeding in children with haemophilia: a clinical significance of Helicobacter pylori infection

For patients with haemophilia, gastrointestinal (GI) bleeding is a life-threatening complication and can be caused by the Helicobacter pylori infection. Among children with haemophilia who had visited with GI bleeding, the prevalence of H. pylori infection and the recurrence rate after H. pylori eradication was investigated. Seven children with haemophilia A with hematemesis (age: 5.3-17.0 years) were evaluated for the causes of GI bleeding and the detection of H. pylori. Gastroendoscopy was done to find the bleeding focus and for further evaluation including rapid urease test and mucosal biopsy. Four patients had dyspepsia and abdominal pain for several weeks or months prior to hematemesis. Three patients did not show any symptoms of bleeding. From gastroendoscopy, four patients were diagnosed as duodenal ulcer, one as H. pylori associated chronic gastritis and one as haemorrhagic gastritis. One patient showing a normal finding was diagnosed with adenoid haemorrhage after nasopharyngoscopy. Helicobacter pylori infection was found in four of six patients with GI bleeding (3, duodenal ulcer; 1, H. pylori associated chronic gastritis). The patients with H. pylori infection had an eradication treatment of triple therapy and no recurrence happened. In children with haemophilia, H. pylori should also be considered as an important cause of GI bleeding. The recurrence of the infection and GI bleeding can be prevented with eradication of H. pylori. Screening test for H. pylori would be needed in children with haemophilia in endemic area.

[Diagnosis and treatment guidelines for Helicobacter pylori infection in Korea]

Eleven years has passed since the guideline of the Korean College of Helicobacter and Upper Gastrointestinal Research group for H. pylori infection was produced in 1998. During this period the research for H. pylori has much progressed that H. pylori is now regarded as the major cause of gastric cancer. The seroprevalence of H. pylori in Korea was found to be decreased especially below the age of 40s and in the area of Seoul-Gyeonggi province, and annual reinfection rate of H. pylori has decreased up to 2.94%. In the aspect of diagnostic tests of H. pylori the biopsy is recommended in the body instead of antrum in the subjects with atrophic gastritis and/or intestinal metaplasia for the modified Giemsa staining or Warthin Starry silver staining. The urea breath test is the test of choice to confirm eradication when follow-up endoscopy is not necessary. Definite indication for H. pylori eradication is early gastric cancer in addition to the previous indications of peptic ulcer including scar and Marginal zone B cell lymphoma (MALT type). Treatment is also recommended for the relatives of gastric cancer patient, unexplained iron deficiency anemia, and chronic idiopathic thrombocytopenic purpura. One or two week treatment of proton pump inhibitor (PPI) based triple therapy consisting of one PPI and two antibiotics, clarithromycin and amoxicillin, is recommended as the first line treatment regimen. In the case of treatment failure, one or two weeks of quadruple therapy (PPI+metronidazole+tetracycline+bismuth) is recommended. Herein, Korean College of Helicobacter and Upper Gastrointestinal Research proposes a diagnostic and treatment guideline based on currently available evidence.

Helicobacter pylori diagnostic tests in children: review of the literature from 1999 to 2009

The array of tests that can be used for diagnosis of Helicobacter pylori infection is large, and it can be confusing to define which test to use particularly in children where results may not be comparable to those obtained in adult patients. Using PubMed, we reviewed the English literature from January 1999 to May 2009 to identify articles that determined sensitivity and specificity of H. pylori invasive and non-invasive diagnostic tests in children. We excluded articles that presented a review of the literature, abstracts, case reports, or series where children's results could not be separated from adult populations. Of the tissue based methods, rapid urease tests have better sensitivity than histology to detect presence of H. pylori; however, histology can detect the pathology associated with disease including gastritis, intestinal metaplasia, and other conditions that could be the cause of the child's symptoms. Culture of gastric tissues or stool has 100% specificity but sensitivity is low. Of the serologic tests, immunoblot has the best sensitivity. The urea breath tests have >75% sensitivity for detection of H. pylori before and after treatment. Immunoassays in stool using monoclonal antibodies have >95% sensitivity for detection of H. pylori before and after treatment. PCR testing can be performed in tissue and stool samples and can detect genes associated to antibiotic resistance. In summary, the current commercial non-invasive tests have adequate sensitivity and specificity for detecting the presence of H. pylori; however, endoscopy with histopathology is the only method that can detect H. pylori and lesions associated with the infection.

Improved performance of a rapid office-based stool test for detection of Helicobacter pylori in children before and after therapy

A modified version of a rapid office based one-step monoclonal immunoassay for detection of Helicobacter pylori antigen in stool samples from children was evaluated against biopsy specimen-based methods and compared to a monoclonal enzyme immunoassay using the same antigen. Blinded stool samples from 185 children (0.3 to 18.2 years) were investigated at the time of upper endoscopy prior to anti-H. pylori therapy; 62 children were H. pylori infected and 123 noninfected according to predefined reference standards. Samples obtained 6 to 8 weeks after anti-H. pylori therapy were available from 58 children (3.8 to 17.7 years) and were compared to results of the [(13)C]urea breath test (14/58 were positive). The rapid stool tests were performed by two independent readers. Of 243 rapid tests performed, 1 (0.4%) was invalid for technical reasons. Equivocal results (very weak line) were reported 16 times by reader 1 and 27 times by reader 2. When equivocal results were considered positive, the two observers agreed on 76 positive and 160 negative results and disagreed on 7 samples (2.9%). The sensitivity was 90.8% for reader 1 and 85.5% for reader 2, and the specificity was 91.0% and 93.4%, respectively. The monoclonal enzyme immunoassay revealed a sensitivity and specificity of 94.7% and 97.6%, respectively. The modified chromatographic immunoassay is a good alternative in settings or situations when the monoclonal enzyme immunoassay or the [(13)C]urea breath test are not available or feasible. In order to improve sensitivity, very weak lines should be considered positive test results.

Helicobacter pylori infection in pediatrics

his review summarizes the articles published on Helicobacter pylori infection in children between April 2008 and March 2009. Recent evidence highlights the decreasing prevalence trend of H. pylori infection and supports both intrafamilial and extrafamilial transmission. The association with various symptoms is still being debated. Interestingly, H. pylori infection seems inversely associated with allergic diseases. Monoclonal stool antigen tests are widely used and accurate for the diagnosis of H. pylori infection, but less accurate in young children. The new biprobe real-time PCR assay applied to stools showed a poor sensitivity in children. Using the urea hydrolysis rate next to the delta over baseline values, the (13)C-urea breath test provides excellent results for all age children, even for young children. Treatment of H. pylori infection remains a challenge, considering suboptimal efficacy of current therapy. Among emerging alternatives, sequential treatment appears promising. The adjunction of probiotics to conventional regimens, although eliciting great interest, has shown limited therapeutic benefit.

Helicobacter pylori infection in children

The review summarizes the articles published on Helicobacter pylori in children between April 2007 and March 2008. Evidence is emerging in different populations including developing countries that the prevalence of H. pylori is declining in all age groups. The reasons for this are unclear but it is unlikely that treatment of infection or improvement in socioeconomic conditions fully explains the decline. For the first time, differences in the inflammatory response between adults and children have been well characterized in a group of adults and children from Chile with similar levels of H. pylori infection. This study suggests that the reduced inflammatory response to H. pylori at a cellular level in children could be the consequence of an enhanced Treg cell response, which in turn down-regulates H. pylori-induced inflammation. The publication of the Paediatric European Register for Treatment of Helicobacter pylori study (PERTH) is important as it demonstrates the advantages of different centers working in collaboration for the benefit of children. It also highlights the fact that while bismuth-based treatment is more effective than proton pump inhibitor-based treatment in children, bismuth preparations are not widely available for use in children.

Diagnosis of Helicobacter pylori

The different invasive and noninvasive diagnostic tests for Helicobacter pylori have been applied mainly in emerging countries. Molecular methods have been developed, especially a test for detection of H. pylori and its clarithromycin resistance directly from stools. The long-term effects of eradication on histologic lesions have been studied in a meta-analysis and the prognostic value of post-treatment in gastric mucosa-associated lymphoid tissue lymphoma has been assessed. An operating link for gastritis assessment (the OLGA staging) has also been published. Attempts to simplify the urea breath test protocol have been made, and new stool antigen tests have been proposed and compared to those previously available.