Evaluation of a novel monoclonal enzyme immunoassay for detection of Helicobacter pylori antigen in stool from children

Optical detection using CRISPR-Cas12a of Helicobacter pylori for veterinary applications

Helicobacter pylori (H. pylori) is a zoonotic gastric microorganism capable of efficient interspecies transmission. Domesticated companion animals, particularly dogs and cats, serve as natural reservoirs for H. pylori. This phenomenon facilitates the extensive dissemination of H. pylori among households with pets. Hence, the prompt and precise identification of H. pylori in companion animals holds paramount importance for the well-being of both animals and their owners. With the assistance of Multienzyme Isothermal Rapid Amplification (MIRA) and CRISPR-Cas12a system, we successfully crafted a highly adaptable optical detection platform for H. pylori. Three sensor systems with corresponding visual interpretations were proposed. This study demonstrated a rapid turnaround time of approximately 45 min from DNA extraction to the result display. Moreover, this platform topped germiculture and real-time PCR in terms of sensitivity or efficiency in clinical diagnoses of 66 samples. This platform possesses significant potential as a versatile approach and represents the premiere application of CRISPR for the non-invasive detection of H. pylori in companion animals, thereby mitigating the dissemination of H. pylori among household members.

Current and Future Perspectives in the Diagnosis and Management of Helicobacter pylori Infection

Helicobacter pylori (Hp) is a prevalent organism infecting almost half the global population. It is a significant concern, given its associated risk of gastric cancer, which is the third leading cause of cancer death globally. Infection can be asymptomatic or present with dyspeptic symptoms. It may also present with alarm symptoms in the case of progression to cancer. Diagnosis can be achieved non-invasively (breath tests, stool studies, or serology) or invasively (rapid urease test, biopsy, or culture). Treatment involves acid suppression and regimens containing several antibiotics and is guided by resistance rates. Eradication is essential, as it lowers the risk of complications and progression to cancer. Follow-up after eradication is similarly important, as the risk of cancer progression remains. There have been many recent advances in both diagnosis and treatment of Hp. In particular, biosensors may be effective diagnostic tools, and nanotechnology, vaccines, and potassium-competitive acid blockers may prove effective in enhancing eradication rates.

Helicobacter pylori Infection in Tripoli, North Lebanon: Assessment and Risk Factors

Helicobacter pylori (H. pylori) infection occurs among half of the general population worldwide, with high geographic variability. Even though H. pylori is the leading cause of several gastric diseases, ranging from gastritis and peptic ulcers to gastric malignancies, such as gastric cancer and mucosa-associated lymphoid tissue lymphoma, most of the infections remain asymptomatic. Early detection and eradication of H. pylori can definitely prevent severe long-term gastric diseases associated with H. pylori. In Lebanon, the prevalence of H. pylori is not well documented, especially in healthy subjects. The aim of this study is to assess H. pylori infections and the associated risk factors in Tripoli, North Lebanon. A cross-sectional study was conducted on 300 healthy Lebanese volunteers, including both children and adults. The H. pylori stool antigens were detected using the Premier Platinum HpSA test. The socio-demographic data, lifestyle characteristics, and gastrointestinal characteristics of all participants were analyzed. Out of the 300 tested volunteer subjects, 31% were found to be positive for H. pylori. A multivariate binary logistic regression analysis for factors associated with H. pylori infection revealed a significant association between H. pylori infection and gastrointestinal disturbances, the crowding index, and occupation. A significant statistical correlation was found between sheesha smoking (p = 0.001) and H. pylori infection. These findings highlight the need for the development of preventive approaches and strategic indications for the appropriate treatment of H. pylori infections in Tripoli, North Lebanon.

<p>Observation of Changes in <em>Helicobacter pylori</em> Antigen and Antibody Positivity According to Non-Invasive Tests Before and After <em>Helicobacter pylori</em> Eradication Therapy in Symptomatic Patients</p>

Background

Non-invasive tests can help with the diagnosis of Helicobacter pylori (H. pylori) infection and in determining patient prognosis following H. pylori eradication therapy. The aim of the study was to detect H. pylori antigens in the stool in symptomatic patients and to observe changes in the antigen test results following H. pylori eradication therapy.

Methods

A prospective study was conducted. Blood, urine and stool samples were collected from 62 dyspeptic patients. Anti-H. pylori IgM and IgG antibodies were detected in the serum by ELISA, anti-H. pylori IgG antibodies were detected in the urine by ICT and H. pylori antigens were detected in the stool by ELISA. Among the 62 patients, 39 (62.90%) were positive with all three methods. These 39 patients were asked to complete a 2-week course of medication and return after 6 weeks following completion of therapy to undergo repeated tests. In total, 3 dropped out of the study.

Results

Among the 62 dyspeptic patients, 41 (66.13%) were positive for serum IgG according to ELISA, 39 (62.90%) were positive for urine IgG according to ICT, 8 (12.90%) were positive for serum IgM according to ELISA, and 42 (67.74%) were positive for HpSA according to ELISA. After eradication therapy, 18 (50.00%) patients were positive for serum IgG, 19 (52.78%) were positive for urine IgG, 4 (11.11%) were positive for serum IgM and 5 (13.88%) were positive for HpSA. The difference in HpSA positivity before and after eradication therapy was statistically significant (P <0.05).

Conclusion

This study involved non-invasive procedures that can be used as first-line screening tools for the detection of active H. pylori infection to observe the role of HpSA test in diagnosis and assessment of prognosis following eradication therapy for H. pylori.

Performances of the IDEIA HpStAR Stool Antigen Test in Detection of Helicobacter pylori Infection Before and After Eradication Treatment in Algerian Children

We aimed to evaluate in an Algerian pediatric population the diagnostic performances of the IDEIA HpStAR noninvasive stool antigen test (Oxoid, Cambridge, UK) to detect Helicobacter pylori infection before and after eradication therapy. A prospective study including 158 symptomatic Algerian children was conducted. Patients were initially diagnosed with invasive (culture, histology, and rapid urease test) and noninvasive tests (urea breath test and IDEIA HpStAR test). Infected patients were treated, and 101 were controlled after treatment with two invasive (culture and histology) and two noninvasive tests (urea breath test and IDEIA HpStAR test). In Algerian children, the IDEIA HpStAR test showed good performances for initial detection of H. pylori infection and also for subsequent control of eradication treatment. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of IDEIA HpStAR test before treatment were 93.6%, 100%, 100%, 87.3%, and 96%, respectively, and those after treatment were 100, 92.8, 78.6, 100, and 94.2%, respectively.

Prevalence of Helicobacter pylori and Its Associated Factors among Healthy Asymptomatic Residents in the United Arab Emirates

The United Arab Emirates (UAE) has been under continuous populational influences from Asia, Europe, and Africa, making it an ideal site for epidemiological studies on Helicobacter pylori. However, there has been a paucity of well-designed prevalence studies on H. pylori from UAE. The aim of this study was to determine the prevalence of H. pylori and its associated risk factors in the UAE. A prospective cross-sectional study was conducted on healthy asymptomatic residents of UAE. Socio-demographic, lifestyle, and gastrointestinal characteristics of participants were obtained through a questionnaire in parallel within the stool sample collection. A total of 350 participants were included in this study and were tested for H. pylori using the stool antigen test (Premier Platinum HpSAT). Out of the total tested study participants, 41% were found to be H. pylori-infected. Logistic regression analysis has shown a significant association between H. pylori infection and gender, age, ethnicity, profession, domestic overcrowding, source of drinking water, and gastrointestinal characteristics of participants. Based on the results from this study, we suggest that preventive measures against H. pylori infection should be considered worthy by public health authorities.

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.

Diagnosis of Helicobacter pylori Using Invasive and Noninvasive Approaches

Helicobacter pylori (H. pylori) as gram-negative and spiral microorganism is responsible for colonization in the gastric microniche for more than 50% of world population. Recent studies have shown a critical role of H. pylori in the development of peptic ulcers, gastric mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. Over the past decade, there has been a sharp interest to use noninvasive tests in diagnosis of the H. pylori infection. During the years after discovery by Marshall and Warren, it has been frequently declared that the rapid urease test (RUT) is one of the cheapest and rapid diagnostic approaches used in detecting the infection. Although the specificity and sensitivity are durable for this test, clinical experiences had shown that the ideal results are only achieved only if we take biopsies from both corpus and antrum at the same time. Given the diagnosis of the H. pylori in clinical samples, gastroenterologists are facing a long list of various molecular and nonmolecular tests. We need more in-depth researches and investigations to correctly generalize rapid and accurate molecular tests determining both bacterial identity and antibiotic resistance profile.

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.

Detection of Helicobacter pylori by Real-Time PCR for 16s rRNA in Stools of NonInfected Healthy Children, Using ELISA Antigen Stool Test as the Gold Standard

BACKGROUND

We previously detected Helicobacter pylori infection by stool antigen ELISA assay in 33-41% of asymptomatic Chilean children between 2-3 years of age, of which 11-20% had a transient infection and 21-22% a persistent infection. A total of 88% of ELISA-positive samples were also rtPCR positive, while 37/133 (33%) of ELISA-negative stool samples were rtPCR positive. The significance of a ELISA-negative/rtPCR-positive sample requires clarification. We aimed to determine whether rtPCR is able to detect persistent infections not detected by ELISA.

MATERIALS AND METHODS

We selected 36 children with an ELISA-negative/rtPCR-positive stool sample, of which 25 were never H. pylori infected according to ELISA, and 11 had a transient infection with an ELISA-positive sample before or after the discordant sample. At least two additional consecutive ELISA-negative samples per child were tested in duplicate by rtPCR for the 16s rRNA gene.

RESULTS

A total of 14 of 78 (17.9%) rtPCR reactions were positive, but only 4/78 (5.1%) were positive in both duplicates, representing a total of 3/36 (8.3%) children with an additional rtPCR-positive sample, only one of whom was persistently negative by ELISA. One child with a transient infection had two positive rtPCR reactions despite negative ELISA samples.

CONCLUSIONS

In H. pylori noninfected or transiently infected children, as determined by stool ELISA, additional ELISA-negative/rtPCR-positive stool samples were found in 8.3% of children, but a possible persistent infection was only identified in 2.7% of children. Thus, the characterization of infection dynamics in children is not being misrepresented by application of stool ELISA. Furthermore, rtPCR does not significantly improve dynamic characterization.

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.

Prevalence and risk factors of Helicobacter pylori infection in asymptomatic Chinese children: a prospective, cross-sectional, population-based study

BACKGROUND

Limited research has been published on current Helicobacter pylori infection rate in asymptomatic children in China.

AIM

To assess current Helicobacter pylori infection rate, distribution characteristics and risk factors in Chinese asymptomatic children.

METHODS

A prospective, cross-sectional, population-based study was performed from 2009 to 2011 in three cities of China. Helicobacter pylori infection was diagnosed by a stool antigen test. Multi-stage cluster random sampling was used to select asymptomatic children including neonates. Socioeconomic details were obtained through a standardised questionnaire.

RESULTS

Among total of 3491 children (0-18 years), the global infection rate was 6.8% and there were no significant differences between genders. Age specific infection rate between regions was significantly different (P < 0.05). The infection rate significantly increased with age (P for trend <0.01). It was low during the newborn (0.6%) to preschool period and was significantly increased in high school students (13.5%) (P < 0.01). Multivariable regression indicated that hand sanitisation, individually served meals, higher education level of mother, above average living space and residence in urban areas were significantly protective against infection (OR 0.749, 0.698, 0.720, 0.838 and 0.770 respectively). Conversely, consuming meals in unsanitised conditions, sharing towels, receiving pre-chewed food from the mother, artificial feeding and family history of gastrointestinal disease were significantly associated with the risk of infection (OR 1.200, 1.965, 2.002, 1.071 and 2.093 respectively).

CONCLUSIONS

Helicobacter pylori infection rate increases with age in Chinese asymptomatic children and is common after 10 years of age. The rate of infection is related to socioeconomic status.

New Diagnostic Strategies for Detection of Helicobacter pylori Infection in Pediatric Patients

Helicobacter pylori (H pylori) is a common chronic bacterial infection that is an important cause of peptic ulcer disease and gastroduodenal disease in children. H pylori is also associated with extragastric manifestations, including growth reduction, iron-deficiency anemia, and idiopathic thrombocytopenic purpura. Current guidelines recommend endoscopy with biopsy for the definitive demonstration of H pylori infection. In contrast to serology, the fecal antigen test and the urea breath test provide reliable, sensitive, and specific results for detecting active H pylori infection in children before and after treatment. The first-line treatment option for pediatric patients is triple therapy with a proton pump inhibitor and 2 antibiotics, which include amoxicillin and clarithromycin or metronidazole. Decreasing eradication rates and the emergence of antibiotic-resistant strains of H pylori have led to the use of other treatments, such as sequential therapy or triple therapy with newer antibiotics, particularly in geographic areas with high rates of antibiotic resistance. Patients should be tested after treatment to confirm eradication, as the absence of symptoms does not necessarily mean that H pylori is no longer present. This clinical roundtable monograph provides an overview of H pylori infection, as well as expert insight into the diagnosis and management of H pylori infection in children.

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.

Association between abnormal gastric function risk and Helicobacter pylori infection assessed by ELISA and 14C-urea breath test

OBJECTIVE

Epidemiological studies found a significant correlation between Helicobacter pylori infection and elevated serum pepsinogen, especially pepsinogen II (PGII), and reduced pepsinogen I (PGI)/PGII ratio. The study aimed to evaluate the association between abnormal gastric function risk and H. pylori infection assessed by H. pylori IgG assay and (14)C-urea breath test (UBT).

METHODS

A total of 1555 subjects who underwent a health check were enrolled. Serum PGI, serum PGII, PGI/PGII ratio, gastrin 17 (G17), H. pylori IgG antibody titer, and UBT results were collected.

RESULTS

Median PGII and G17 levels were higher, but PGI/PGII ratio was lower in H. pylori-seropositive compared with seronegative participants (P<0.001, respectively). Similar effects were demonstrated by UBT. The consistency between H. pylori IgG assay, and UBT results were 86.9%, 82.29%, and 84.64% in individuals with normal gastric function, but only 73.4%, 67.98%, and 74.6% in those with abnormal gastric function. The correlation coefficients for H. pylori infection and abnormal gastric function diagnosed by PGI/PGII <7 were 0.336 (P<0.001) by H. pylori IgG assay and 0.231 (P<0.001) by UBT, diagnosed by PGII ≥ 8.25 µg/L were 0.594(P<0.001) by H. pylori IgG assay and 0.493 (P<0.001) by UBT, diagnosed by G17 >3 pmol/L was 0.469 (P<0.001) by H. pylori IgG assay and 0.394 (P<0.001) by UBT. The odds ratios (ORs) (95% confidence intervals) of abnormal gastric function were 7.477 (5.278-10.594), 19.204 (14.526-25.387), and 7.921 (6.286-9.982) comparing positive versus negative by H. pylori IgG assay and 4.084 (2.98-5.598), 9.552 (7.494-12.174), and 5.402 (4.335-6.731) comparing positive versus negative by UBT.

CONCLUSIONS

H. pylori infection assessments by antibody-based or bacterial component-based detection are both related with abnormal gastric function. Moreover, serum H. pylori IgG assay was stronger associated with abnormal gastric function than UBT assay.

Comparison of stool antigen test with gastric biopsy for the detection of Helicobacter Pylori infection

Objective: Helicobacter Pylori (H.pylori) is one of the most important causes of dyspepsia and diagnosis can be made by invasive or non-invasive methods. One of the non-invasive methods, H.pylori stool antigen test (HpSA) is simple, fast and relatively inexpensive. According to this view with regard to gastric biopsy as a gold standard the sensitivity, specificity, positive and negative predictive values of this method were calculated.

Methodology: Stool samples of 61 patients who underwent upper endoscopy and gastric biopsy due to dyspepsia were evaluated for H. Pylori stool antigen using sandwich ELISA method.

Results: From the 61 patients who participated in this study, H.pylori was diagnosed in 38 (62.3%) gastric biopsies, 25(66%) of these had positive HpSA test. Also, of 27 (37.7%) positive HpSA cases, H.pylori was seen in 25 gastric biopsies. For this method, sensitivity of 66% with 93% positive predictive value was calculated. Also, 91% specificity with 62% negative predictive value was estimated.

Conclusion: High positive HpSA indicates high risk of H.pylori infection and high specificity shows that the likelihood of false positive is low. Therefore, physicians can trust on this method and start patient`s treatment.

Helicobacter pylori infection in infants and toddlers in South America: concordance between [13C]urea breath test and monoclonal H. pylori stool antigen test

Accurate noninvasive tests for diagnosing Helicobacter pylori infection in very young children are strongly required. We investigated the agreement between the [(13)C]urea breath test ([(13)C]UBT) and a monoclonal ELISA (HpSA) for detection of H. pylori antigen in stool. From October 2007 to July 2011, we enrolled 414 infants (123 from Brazil and 291 from Peru) of ages 6 to 30 months. Breath and stool samples were obtained at intervals of at least 3 months from Brazilian (n = 415) and Peruvian (n = 908) infants. [(13)C]UBT and stool test results concurred with each other in 1,255 (94.86%) cases (kappa coefficient = 0.90; 95% confidence interval [CI] = 0.87 to 0.92). In the H. pylori-positive group, delta-over-baseline (DOB) and optical density (OD) values were positively correlated (r = 0.62; P < 0.001). The positivity of the tests was higher (P < 0.001; odds ratio [OR] = 6.01; 95% CI = 4.50 to 8.04) in Peru (546/878; 62.2%) than in Brazil (81/377; 21.5%) and increased with increasing age in Brazil (P = 0.02), whereas in Peru it decreased with increasing age (P < 0.001). The disagreement between the test results was associated with birth in Brazil and female gender but not with age and diarrhea. Our results suggest that both [(13)C]UBT and the stool monoclonal test are reliable for diagnosing H. pylori infection in very young children, which will facilitate robust epidemiological studies in infants and toddlers.

Dynamics of Helicobacter pylori detection in stools during the first 5 years of life in Chile, a rapidly developing country

BACKGROUND

: Helicobacter pylori colonization/infection can be transitory or persistent, conditions that have not been thoroughly evaluated in young children. We aimed to characterize the dynamics of H. pylori stool detection and to determine host and environmental factors and symptoms associated with persistence.

METHOD

: In a 5-year cohort study, we followed-up infants from birth with clinic visits every 3 months. Symptoms and environmental risk factor survey and a stool sample for H. pylori antigen detection were requested in every visit. Secretor/ABH histo-blood group phenotype was determined in saliva.

RESULTS

: Overall, 218 of 1456 (15%) stool samples were positive for H. pylori and 39 of 96 (41%) children had at least 1 positive sample. Stool detection was transitory in 16 of 39 (41%), persistent in 19 (49%) and undetermined in 4 (10%) children. Persistence was acquired largely during the first 24 months (17/19 cases) and was associated with nonsecretor phenotype (32% versus 0% for transitory infection; P = 0.02) and daycare attendance (67% versus 26% for never infected; P = 0.019). Symptoms possibly associated with persistence were referred in only 1 child.

CONCLUSIONS

: Nearly 20% of this Chilean cohort had persistent H. pylori stool sample detections during the first 5 years of life, acquired mostly during the first 24 months. Persistence was significantly associated with nonsecretor phenotype and daycare attendance, and possibly associated gastrointestinal symptoms were rare. This relatively common group of young children with persistent H. pylori colonization/infection will require further study.

Evidence-based guidelines from ESPGHAN and NASPGHAN for Helicobacter pylori infection in children

OBJECTIVE

As the clinical implications of Helicobacter pylori infection in children and adolescents continue to evolve, ESPGHAN and NASPGHAN jointly renewed clinical guidelines using a standardized evidence-based approach to develop updated recommendations for children and adolescents in North America and Europe.

METHODS

An international panel of 11 pediatric gastroenterologists, 2 epidemiologists, 1 microbiologist, and 1 pathologist was selected by societies that developed evidence-based guidelines based on the Delphi process with anonymous voting in a final face-to-face meeting. A systematic literature search was performed on 8 databases of relevance including publications from January 2000 to December 2009. After excluding nonrelevant publications, tables of evidence were constructed for different focus areas according to the Oxford classification. Statements and recommendations were formulated in the following areas: whom to test, how to test, whom to treat, and how to treat. Grades of evidence were assigned to each recommendation based on the GRADE system.

RESULTS

A total of 2290 publications were identified, from which 738 were finally reviewed. A total of 21 recommendations were generated, and an algorithm was proposed by the joint committee providing evidence-based guidelines on the diagnostic workup and treatment of children with H pylori infection.

CONCLUSIONS

These clinical practice guidelines represent updated, best-available evidence and are meant for children and adolescents living in Europe and North America, but they may not apply to those living on other continents, particularly in developing countries with a high H pylori infection rate and limited health care resources.

Fermented soybean liquid alleviated peptic ulcer through the destruction of acidic proton pump rather than suppression of urease of Helicobacter pylori: a kinetic analysis

Fermented soybean liquid (FSL) has been well cited for its broad spectrum of biological effects, yet its documented gastropeptic ulcer (GPU) ameliorating effect is still lacking. It was hypothesized that to avoid the injury exerted by gastric fluid, HP has to be sheltered in chyme emulsions immediately on infection. The HP urease (HPU) and the acidic proton pump (PP) may act as the "two-point pH modulator" to maintain an optimum pH between 6 and 7, and FSL is able to destroy such a modulating mechanism. FSL exhibited higher contents of isoflavonoids (2.5-17.3-fold) and essential amino acids (1.5-4.0-fold) than the nonfermented. FSL administered at 1 g/20 mL tid for 3 months eradicated Helicobacter pylori (HP) by 82% in 37 volunteers having GPU (p < 0.20); simultaneously, the plasma conjugated diene and TBARs levels were significantly resumed (p < 0.05). Kinetic analysis based on the conventional "urease theory" revealed that a cluster of 2.0 × 10(9) of HP cells is required for a single attack in the gastric lumen at pH 1.0-2.5. To verify the hypothesis, chyme-shelter testing was conducted in artificial gastric fluid (pH 2.4 ± 0.20). Results showed the HP cell viability was time- and size-dependent. At 20 min of contact time, the viability was 100, 4.2, 31.4, 43.3, 57.2, and 82.6%, respectively, in intact, dispersed, and particulate chymes (mesh sizes 80, 60, 40, and 20). The corresponding data became 96.2, 0.0, 14.5, 18.5, 21.3, and 28.6%, respectively, at a contact time of 40 min. Conclusively, the kinetic analysis and the chyme-shelter testing revealed that direct infection by bare HP cells is unlikely in real status. FSL is beneficial to GPU most probably due to its ability to raise blood alkalinity levels, destroying the PP and its ROS suppressing effect.

Utility of stool sample-based tests for the diagnosis of Helicobacter pylori infection in children

OBJECTIVE

Helicobacter pylori antigen or DNA in stool are meant to detect the bacteria; however, in children the colonization of the gastric mucosa by H pylori is usually weak and fecal excretion of antigen or DNA varies considerably, challenging the utility of these tests in this age group. The aim of the present study was to carry out a systematic review and meta-analysis to evaluate the performance of stool H pylori DNA and antigen tests for the diagnosis of infection in children.

METHODS

We conducted a systematic review and meta-analysis to assess the accuracy of stool tests for diagnosis of H pylori infection in children. We searched PubMed, EMBASE, and LILACS databases. Selection criteria included participation of at least 30 children and the use of a criterion standard for H pylori diagnosis. In a comprehensive search, we identified 48 studies.

RESULTS

Regarding antigen-detection tests, enzyme-linked immunosorbent assay (ELISA) monoclonal antibodies showed the best performance, with sensitivity and specificity of 97%, positive likelihood ratio (LR+) of 29.9, and negative likelihood ratio (LR-) of 0.03. ELISA polyclonal antibodies had sensitivity of 92%, specificity of 93%, LR+ of 16.2, LR- of 0.09, and high heterogeneity (P < 0.0001). One-step monoclonal antibody tests demonstrated sensitivity of 88%, specificity of 93%, LR+ of 10.6, and LR- of 0.11. For DNA detection, polymerase chain reaction-based test showed sensitivity of 80.8%, specificity of 98%, LR+ of 17.1, and LR- of 0.18.

CONCLUSIONS

Detection of H pylori antigen in stools with ELISA monoclonal antibodies is a noninvasive efficient test for diagnosis of infection in children. One-step tests showed low accuracy and more studies are needed to obtain a useful office-based screening test. The available molecular tests are still unreliable.

Evaluation of a new antigen for diagnosis of Helicobacter pylori infection in stool of adult and children

BACKGROUND

Nowadays, there is an increasing interest in noninvasive methods to diagnose Helicobacter pylori infection. Indeed, they can profitably replace endoscopy in predicting the diagnosis. The stool antigen test for H. pylori is a noninvasive immunoassay to diagnose active infection with this bacterium in human fecal samples. The aim of this study was detection of alkyl hydroperoxide reductase protein (AhpC) antigen by immunoblotting in stool samples for diagnosis of H. pylori.

MATERIALS AND METHODS

Chromosomal DNA from H. pylori was isolated. AhpC gene was amplified by PCR, These amplicons were cloned into pTZ57R/T cloning vector then subcloned into pQE30 expression vector and overexpressed using isopropyl-beta-D-thiogalactopyranoside in E. coli M15. AhpC protein was purified by affinity chromatography. Rabbits were immunized with the purified AhpC protein for the production of antibodies. To determine the accuracy of the test for diagnosing H. pylori infection from stool, we evaluated 84 patients (6-81 years old) using Western blot analysis by rabbit anti-AhpC antibody. Positive rapid urease test on biopsy samples was considered as the gold standard.

RESULTS

AhpC gene was overexpressed, and AhpC protein was purified. Rabbit anti-AhpC antibody produced after immunization with the purified AhpC protein. By immunoblotting, we detected AhpC protein in the positive stool samples. The test showed a 83.3% sensitivity (95% CI: 69.8-92.5%) and a 91.7% specificity (95% CI: 77.5-98.2). Among the children, the sensitivity was 88.2% (95% CI: 63.6-98.5) and the specificity was 100% (95% CI: 69.2-100); in adults, the sensitivity and specificity were 80.6% (95% CI: 62.5-92.5) and 88.5% (95% CI: 69.8-97.6), respectively.

CONCLUSIONS

Using of AhpC antigen for diagnosis of H. pylori infection is a useful noninvasive method, accurate in adolescents and children, and can be used for the development of a stool antigen detection kit for H. pylori.

The effect of Helicobacter pylori infection on growth velocity in young children from poor urban communities in Ecuador

OBJECTIVE

To characterize the potential effects of Helicobacter infections on growth velocity in low socioeconomic status young children in a developing country.

METHODS

Children were recruited in poor suburbs of Quito, Ecuador. Normally nourished, mildly and substantially malnourished children (defined using weight-for-age Z-scores at recruitment) formed equal strata. Six height and weight measurements were collected during one year. Enrollment and exit serum samples were analyzed for anti-Helicobacter IgG and exit non-diarrheal feces tested for Helicobacter antigen.

RESULTS

Among 124 participants (enrollment age 19 ± 9 months), 76 (61%) excreted fecal antigen at exit (were infected). Of these, 44 were seropositive at least once (chronic infections) and 32 tested seronegative both times (new or acute phase infections). The adjusted linear growth velocity during follow-up in children with new infections was reduced by 9.7 (3.8, 15.6) mm/year compared to uninfected controls and 6.4 (0.0, 12.9) mm/year compared to children with chronic infections. The effects of Helicobacter infections on ponderal growth were not significant.

CONCLUSION

These results suggest that linear growth velocity is reduced in young children during the initial phase of Helicobacter infection.

Validation of a monoclonal stool antigen test for diagnosing Helicobacter pylori infection in young children

BACKGROUND AND OBJECTIVE

The monoclonal stool antigen test for diagnosing Helicobacter pylori infection in children has been tested in developed countries, showing sensitivity and specificity higher than 90%. However, its accuracy in young children from developing countries is not well established. The aim of the study was to determine the accuracy of the monoclonal stool antigen test for diagnosing H pylori infection in children up to 7 years old.

PATIENTS AND METHODS

Two hundred seventy-six patients (53.6% female; ages 0.35-6.99 years) were evaluated. Gold standard positive culture or positive histology and rapid urease tests were performed. The test (Amplified IDEIATM Hp StAR) was done according to the manufacturer's instructions. Results were expressed as optical density (OD) and an OD more than or equal to 0.190 was considered positive. Additionally, a receiver operating characteristic curve was used to find the best cutoff.

RESULTS

The monoclonal stool antigen test for diagnosing H pylori infection showed 100% sensitivity (95% confidence interval [CI] 92.7%-100%) and 76.2% specificity (95% CI 70.1%-81.4%), considering the manufacturer's cutoff. After setting a new cutoff with the receiver operating characteristic curve (OD = 0.400), sensitivity remained 100% (95% CI 92.7%-100%), but the specificity improved to 97.7% (95% CI 94.7%-99%). At ages up to 2 years, sensitivity was 100% (95% CI 43.8%-100%) and specificity was 100% (95% CI 92.4%-100%); at ages 2 to 4 years, 100% (95% CI 80.6%-100%) and 97.6% (95% CI 96%-99.2%); at ages older than 4 years, 100% (95% CI 88.6%-100%) and 96.6% (95% CI 94.7%-98%), respectively.

CONCLUSIONS

The monoclonal stool antigen test is accurate for diagnosing H pylori in children younger than 7 years old, but it must be locally validated in order to find the best cutoff for each population.

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 children

Helicobacter pylori infection is a common problem in pediatric practice, and its acquisition is related with poor socioeconomic conditions. Although the organism is thought to be responsible for many diseases, only a handful of them have a direct causal relationship. At present, only a small number of children with well-defined clinical syndromes are benefited from testing and treatment. The treatment should include at least two antibiotics with a proton pump inhibitor.

Antibody-based detection tests for the diagnosis of Helicobacter pylori infection in children: a meta-analysis

Background

Numerous serologic tests are available for the diagnosis of H. pylori infection in children. Common designs of antibody-based detection tests are ELISA and Western Blot (WB). For developing countries with limited laboratory resources and access, ELISA would be the preferred method because of its simplicity, lower cost and speed. Although in adults ELISA has proven to be highly accurate in diagnosing H. pylori infection; in children, it has shown variable accuracy.

Methods/Findings

We conducted a systematic review and meta-analysis to assess the accuracy of antibody-based detection tests for the diagnosis of H. pylori infection in children. Selection criteria included participation of at least 30 children and the use of a gold standard for H. pylori diagnosis. In a comprehensive search we identified 68 studies. Subgroup analyses were carried out by technique, immunoglobulin class, and source of test (commercial and in-house). The results demonstrated: 1) WB tests showed high overall performance, sensitivity 91.3% (95% CI, 88.9–93.3), specificity 89% (95% CI, 85.7–91.9), LR+ 8.2 (95% CI, 5.1–13.3), LR− 0.06 (95% CI, 0.02–0.16), DOR 158.8 (95% CI, 57.8–435.8); 2) ELISA-IgG assays showed low sensitivity 79.2% (95% CI, 77.3–81.0) and high specificity (92.4%, 95% CI, 91.6–93.3); 3) ELISA commercial tests varied widely in performance (test for heterogeneity p<0.0001); and 4) In-house ELISA with whole-cell antigen tests showed the highest overall performance: sensitivity 94% (95% CI, 90.2–96.7), specificity 96.4% (95% CI, 94.2–97.9), LR+ 19.9 (95% CI, 7.9–49.8), LR− 0.08 (95% CI, 0.04–0.15) DOR 292.8 (95% CI, 101.8–841.7).

Conclusions/Significance

WB test and in-house ELISA with whole-cell antigen tests are the most reliable tests for the diagnosis of H. pylori infection in children. Antigens obtained from local strains of the community could partially explain the good overall accuracy of the in-house ELISA. Because of its cost and technical demands, in-house ELISA might be more suitable for use in developing countries.

Low prevalence of Helicobacter pylori infection in Canadian children: a cross-sectional analysis

BACKGROUND

The incidence and prevalence rates of childhood Helicobacter pylori infection vary greatly by nation, with infection rates of 8.9% to 72.8% reported in developed and developing countries, respectively. To date, few studies have assessed the prevalence of H pylori in Canadian children, with studies limited to Aboriginal communities and single tertiary care centres from Ontario and Quebec.

OBJECTIVES

To determine the prevalence of H pylori in consecutive children referred to three Canadian tertiary care academic centres for upper gastrointestinal (GI) endoscopy due to upper GI symptoms, and to determine the sensitivity and specificity of the carbon-13-labelled urea breath test, the rapid urease test and the H pylori stool monoclonal antigen test.

RESULTS

Two hundred four patients were recruited. The prevalence of H pylori was 7.1%. Of the H pylori-positive patients, 41.7% were male, with a mean age of 10.3 years. Ethnic minorities accounted for 42% of the H pylori-positive patients. Consistent with previous observations, the sensitivity and specificity of the carbon-13-labelled urea breath test were 1.0 and 0.98, respectively. The sensitivity and specificity of the rapid urease test were 1.0 and 0.99, respectively. Stool samples were collected from 34 patients from one centre, with a sensitivity and specificity of 1.0 and 0.68, respectively. No defining symptoms of H pylori infection were evident and no peptic ulcer disease was demonstrated.

CONCLUSION

H pylori infection rates in Canadian children with upper GI symptoms are low, and are lower than those reported for other developed countries. Further studies are required in Canada to determine the prevalence in the general population and specifically in the populations at risk.

Diagnosis of Helicobacter pylori infection in a high-prevalence pediatric population: a comparison of 2 fecal antigen testing methods and serology

OBJECTIVES

Accurate methods for diagnosing active Helicobacter pylori infection in children have been limited to invasive or time-consuming techniques. Recently, fecal antigen testing has been used successfully for the diagnosis of H pylori infection in the pediatric population. We compared 2 monoclonal fecal antigen diagnostic methods in a population of children with a suspected high prevalence of H pylori infection. We also assessed the diagnostic performance of H pylori immunoglobulin G serology.

MATERIALS AND METHODS

In a cross-sectional study of African refugee children (<16 years) we compared an immunochromatographic technique (ICT) and serology with a monoclonal fecal antigen enzyme immunoassay (MFAT) method for the detection of active H pylori infection. Following the manufacturer's instructions, an optical density of >or=0.190 was used as a cutoff for MFAT. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Of the 193 eligible children enrolled, active H pylori infection was detected in 149 of 182 (81.9%) in whom MFAT was performed. The prevalence of active infection increased with age; children with active infection were significantly older, and there were no sex differences. ICT and serology underperformed in comparison with MFAT (ICT sensitivity 74.6%, specificity 63.6%, positive predictive value 89.8%, negative predictive value 36.8%; and serology sensitivity 57.9%, specificity 77.4%, positive predictive value 92.0%, negative predictive value 29.9%).

CONCLUSIONS

Monoclonal enzyme immunoassay fecal antigen testing is a practical and feasible alternative to traditional invasive diagnostic methods in high-prevalence pediatric populations. Neither immunochromatography nor serology is useful for the diagnosis of active H pylori infection in these children.

Evaluation of a novel monoclonal-based antigen-in-stool enzyme immunoassay (Premier Platinum HpSA PLUS) for diagnosis of Helicobacter pylori infection in Vietnamese children

BACKGROUND

Helicobacter pylori infection is difficult to diagnose in children, especially in developing countries where noninvasive methods such as urea breath test are often not available. We evaluate the sensitivity and specificity of a new monoclonal antibody-based antigen-in-stool enzyme immunoassay (Premier Platinum HpSA PLUS) for diagnosis of H. pylori infection in Vietnamese children.

MATERIALS AND METHODS

Sensitivity of the antigen-in-stool test was evaluated in 232 children, 3-15 years of age, who were positive for H. pylori infection by culture from biopsies. For evaluation of the specificity 98 children of similar age with nongastrointestinal conditions and who were negative for H. pylori infection by serologic assays were included with blood and stool samples.

RESULTS

Of the 232 culture-positive children, 224 were also positive by Premier Platinum HpSA PLUS. Of the 98 control children, 93 were H. pylori negative also in the stool test. The sensitivity of Premier Platinum HpSA PLUS was thus 96.6% (95% CI 93.3-98.5) and the specificity was 94.9% (95% CI 88.5-98.3).

CONCLUSIONS

The findings have demonstrated Premium Platinum HpSA PLUS to be a reliable method for detection of H. pylori infection also in children in our area.

Evaluation of the monoclonal stool antigen test for Helicobacter pylori in an Asian population with dyspepsia

OBJECTIVE

Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori.

METHODS

Consecutive new patients with dyspepsia, referred to the endoscopy unit were recruited. At endoscopy, biopsies were taken for rapid urease tests and histology. Stool specimens were collected before any therapy was given and were tested for H. pylori using the monoclonal SAT HpSTAR test. Samples were collected from 90 patients. The stool antigen results were compared with the results of rapid urease tests and histopathology, which were used together as the gold standard test in the diagnosis of H. pylori.

RESULTS

Of the 90 patients tested, 45 were H. pylori positive and 45 were H. pylori negative. There was one false positive and one false negative test. The sensitivity, specificity, positive predictive value and negative predictive value for the Hp STAR were identical: 97.8% with a 95% confidence interval of 88.2-99.9%. The diagnostic accuracy was 97.8% with a 95% confidence interval of 92.2-99.7%.

CONCLUSION

The monoclonal stool antigen test, HpSTAR is a highly accurate test for the diagnosis of H. pylori.

Helicobacter pylori and Helicobacter heilmannii in untreated Bulgarian children over a period of 10 years

The aims of the study were to evaluate the incidence of Helicobacter pylori and Helicobacter heilmannii in untreated Bulgarian children from 1996 to 2006, to analyse the performance of diagnostic tests, and to look at H. pylori density in specimens by culture. Antral specimens from children with chronic gastritis (n=513), peptic ulcers (n=54) and other diseases (n=91) were evaluated by direct Gram staining (DGS), in-house rapid urease test (RUT) and culture. The living environment and semi-quantitative H. pylori density were assessed in 188 and 328 children, respectively. H. pylori infection was found in children with ulcers (77.8 %), chronic gastritis (64.5 %) and other diseases (36.3 %). Half (51.4 %) of patients aged 1-5 years and 77.4 % of those aged 16-17 years were H. pylori-positive. Of all children, 328 (49.8 %) showed positive DGS, 184 (28 %) had a positive RUT, and 386 (58.7 %) were culture-positive. Unlike gastric mucus specimens, frozen biopsy specimens provided reliable diagnosis. H. heilmannii was observed in two (0.3 %) children. High H. pylori density (growth into all quadrants of plates) was found in 18 % of 328 children evaluated, involving 31 % of ulcer and 16.7 % of non-ulcer patients. H. pylori infection was more common in rural children with chronic gastritis (91.3 %) than in the remainder (66.7 %). In conclusion, H. pylori infection was common in symptomatic Bulgarian children. The infection prevalence was >77 % in patients aged 16-17 years, in children with a duodenal ulcer, and in rural patients. H. heilmannii infection was uncommon. The performance of the bacterial culture was good. The impact of H. pylori density on the clinical expression and eradication of the infection requires further evaluation. The results highlight the need for routine H. pylori diagnosis in rural children with chronic gastritis.

Immunochromatographic monoclonal test for detection of Helicobacter pylori antigen in stool is useful in children from high-prevalence developing country

BACKGROUND

Tests to detect Helicobacter pylori antigens in feces for diagnosis of infection in children demonstrate controversial results. One novel and fast monoclonal test improves diagnostic accuracy in adults, but clinical evidence of its usefulness at pediatric age is insufficient to date. The objective of this work was to evaluate the diagnostic accuracy of this test in a sample of Mexican children.

METHODS

We conducted a transversal study in 150 selected children with digestive symptoms suggestive of organic disease in whom a clinical history was conducted in addition to a fast monoclonal test (ImmunoCardSTAT HpSA, Meridian Diagnostics) performed by immunochromatography. Patients were submitted to endoscopy and histopathologic study.

RESULTS

Of the 150 children (mean age 7.8 +/- 4.7 years), 107 (71.3%) were positive for the test, and presence of H. pylori was confirmed histologically in 109 (72.7%) children, with sensitivity of 96.3% (95% CI = 95.8-96.8), specificity of 95.1% (95% CI = 93.9-96.4), and accuracy of 96.0% (95% CI, -95.6 to -96.3); pretest probability was 0.73, while post-test probability was 0.98. Infection rate and test accuracy increased with age.

CONCLUSIONS

This test is useful for detecting H. pylori infection in children of all ages, and is a good alternative for screening studies in developing countries with elevated prevalence, due to its being fast, noninvasive, inexpensive, and easy to carry out.

Evaluation of a novel rapid one-step monoclonal chromatographic immunoassay for detection of Helicobacter pylori in stool from children

A new rapid office-based one-step monoclonal immunoassay (RAPID Hp StAR, DakoCytomation, Cambridge, UK) for detection of Helicobacter pylori antigen in stool was evaluated in children against invasive diagnostic methods and compared to the results of a monoclonal EIA targeting the same antigen (Amplified IDEIA Hp StAR, DakoCytomation, Cambridge, UK). Coded stool samples from 118 symptomatic children (0.3-18.8 years) were investigated prior to any anti-H. pylori therapy. Fifty-four children were H. pylori infected defined by positive culture and/or two other positive tests ((13)C-urea breath test, histology, rapid urea test), the remaining 64 children showed concordant negative results. Thirty-four infected children (4.8-17.8 years) were monitored with (13)C-urea breath test (five remained positive) and stool test 6-8 weeks after anti-H. pylori therapy. The immunoassays were independently read by two investigators. The monoclonal EIA showed excellent sensitivity and specificity before (98% and 100%, respectively) and after therapy (100%; 96.2%). The rapid immunoassay was invalid for technical reasons in nine samples (5.9%). The two observers agreed in 31 positive and 93 negative results, but had discordant results in 17 samples (11.2%). Overall, the rapid test showed a poor sensitivity (63.8%-71.1%), but a good specificity (91.1%-96.2%) before treatment. We conclude that the new office based monoclonal enzyme immunoassay for diagnosis of H. pylori should be modified to improve sensitivity, inter-observer-variability and some technical problems. In contrast, the monoclonal EIA stool test is highly reliable, both pre- and post therapy, and equivalent to the (13)C-urea breath test.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

Evaluation of the novel Helicobacter pylori ClariRes real-time PCR assay for detection and clarithromycin susceptibility testing of H. pylori in stool specimens from symptomatic children

The aim of the present study was to evaluate the Helicobacter pylori ClariRes assay (Ingenetix, Vienna, Austria) for the detection of H. pylori infection and the simultaneous clarithromycin susceptibility testing of the H. pylori isolates in stool samples from 100 symptomatic children. The results obtained by this novel biprobe real-time PCR method were directly compared with the results obtained from histological examination of gastric biopsy specimens, culturing, the [13C]urea breath test, and a monoclonal antibody-based stool antigen enzyme immunoassay (EIA). Fecal specimens from all 54 children who were shown to be noninfected by "gold standard" tests gave true-negative PCR results (specificity, 100%). Of the remaining 46 individuals with a positive H. pylori status, 29 were found to be positive by real-time PCR (sensitivity, 63%). For these 29 cases, the H. pylori ClariRes assay confirmed all results from phenotypic clarithromycin susceptibility testing by Etest. In summary, this investigation demonstrates that detection of Helicobacter DNA in stool samples by real-time PCR is a difficult task and that this method cannot replace the stool antigen EIA (sensitivity, 95.7%) for the accurate diagnosis of H. pylori infection in children.

Infantile hypertrophic pyloric stenosis: an infectious cause?

The aetiology of infantile hypertrophic pyloric stenosis (IHPS) remains unclear. The aim of this study was to test the hypothesis that a common bacterium, Helicobacter pylori (HP) may be implicated in the pathogenesis of IHPS. Thirty-nine consecutive infants with confirmed IHPS had their stool analysed with an enzyme immunoassay for the presence of HP. An age/sex-matched group of infants with unrelated surgical conditions were also tested. No positive results for the presence of HP stool antigen were obtained in the study nor the control group. The results of this study demonstrate no causative link between HP and IHPS. A genetic basis has been implicated for IHPS. However, evidence does exist that IHPS is a condition acquired after birth and that an infective agent may be involved in the pathogenesis. Further studies are required to elucidate perinatal factors that may induce the expression of this condition in a genetically sensitive individual.

Usefulness of a serological panel test in the assessment of gastritis in symptomatic children

BACKGROUND

Non-invasive methods are advisable for the detection of Helicobacter pylori-related chronic gastritis in pediatric patients. Serum pepsinogens I and II (sPGII and sPGII), gastrin-17 (G-17) and anti-H. pylori antibodies (IgG-Hp) have been proposed as a 'serological gastric biopsy'.

AIM

To assess H. pylori infection and to evaluate gastric mucosa status in a pediatric population by means of serological parameters such as sPGI, sPGII, G-17 and IgG-Hp.

METHODS

45 consecutively children evaluated for upper gastrointestinal symptoms were analyzed. All children were submitted to upper gastrointestinal endoscopy with biopsies. Serum samples were analyzed for IgG-Hp, sPGII, sPGI and G-17 (Biohit, Helsinki, Finland).

RESULTS

18 children had H. pylori-related mild or moderate non-atrophic chronic gastritis. They presented significantly higher mean levels of sPGII and of IgG-Hp than negative ones, either under or up to 10 years. sPGI showed significantly increased levels in H. pylori-positive patients only over 10 years. G-17 levels were not different between H. pylori-positive and -negative ones. The best cut-offs of IgG-Hp, sPGII and of product IgG-Hp x sPGII, to identify H. pylori infection, were 30 IU/l, 9 microg/l, and 241 IU/l x microg/l, respectively. The product IgG-Hp x sPGII identified H. pylori infection with a 100% sensitivity, 92% specificity, 90% positive predictive value and 100% negative predictive value. IgG-Hp and IgG-Hp showed a correlation (r = 0.94; p < 0.001).

CONCLUSIONS

Combined analysis of sPGII and IgG-Hp antibody levels could be recommended as a non-invasive panel for the assessment of H. pylori-related histological alterations of gastric mucosa in childhood.

Prospective multicentre study on antibiotic resistance of Helicobacter pylori strains obtained from children living in Europe

AIM

To prospectively assess the antibacterial resistance rate in Helicobacter pylori strains obtained from symptomatic children in Europe.

METHODS

During a 4-year period, 17 paediatric centres from 14 European countries reported prospectively on patients infected with H pylori, for whom antibiotic susceptibility was tested.

RESULTS

A total of 1233 patients were reported from Northern (3%), Western (70%), Eastern (9%) and Southern Europe (18%); 41% originated from outside Europe as indicated by mother's birth-country; 13% were <6 years of age, 43% 6-11 years of age and 44% >11 years of age. Testing was carried out before the first treatment (group A, n = 1037), and after treatment failure (group B, n = 196). Overall resistance to clarithromycin was detected in 24% (mean, A: 20%, B: 42%). The primary clarithromycin resistance rate was higher in boys (odds ratio (OR) 1.58; 1.12 to 2.24, p = 0.01), in children <6 years compared with >12 years (OR 1.82, 1.10 to 3.03, p = 0.020) and in patients living in Southern Europe compared with those living in Northern Europe (OR 2.25; 1.52 to 3.30, p<0.001). Overall resistance rate to metronidazole was 25% (A: 23%, B: 35%) and higher in children born outside Europe (A: adjusted. OR 2.42, 95% CI: 1.61 to 3.66, p<0.001). Resistance to both antibiotics occurred in 6.9% (A: 5.3%, B: 15.3%). Resistance to amoxicillin was exceptional (0.6%). Children with peptic ulcer disease (80/1180, 6.8%) were older than patients without ulcer (p = 0.001).

CONCLUSION

The primary resistance rate of H pylori strains obtained from unselected children in Europe is high. The use of antibiotics for other indications seems to be the major risk factor for development of primary resistance.

Helicobacter pylori and Clostridium difficile in cystic fibrosis patients

We describe the prevalence of H. pylori and toxigenic Clostridium difficile (CD) infection and its relationship with gastrointestinal symptoms and pancreatic sufficiency (PS) or insufficiency (PI) in cystic fibrosis (CF) patients. Stool specimens from 30 consecutive patients with CF, aged 1-44, and from 30 healthy similarly aged subjects were tested for the H. pylori antigen by specific monoclonal antibodies and for CD toxins by Tox A/B assay and Tox A assay. CF patients were assessed clinically and tested for specific H. pylori serum antibodies and for mutations. In CF patients, the prevalence of H. pylori antigen was 16.6% (5/30), compared to 30% (9/30) in controls. Of the 26 CF patients with PI, only 2 (7.6%) were infected by H. pylori, compared with 3 of the 4 (75%) patients with PS (P=0.001). H. pylori infection was diagnosed in 3 of 5 (60%) CF patients carrying mild mutations, compared to 1 of 25 (4%) CF patients carrying severe mutations (P=0.01). Fourteen of 30 (46.6%) stool specimens from CF patients tested positive in the ToxA/B assay, and 3 of 14 tested positive for ToxA. No significant differences in antibiotic use, severity of lung disease, PI, chronic abdominal pain, or genotype were found between the two groups. None of the controls was positive for CD toxins. Prevalence of H. pylori infection in CF patients was lower than in similarly aged non-CF controls. CF patients with PI or a history of distal intestinal obstruction syndrome and those carrying mutations associated with a severe phenotype were protected against H. pylori infection. Almost half of the CF patients were asymptomatic carriers of CD producing mostly toxin B. More studies are needed to confirm our results in a larger group of CF patients.

High accuracy of noninvasive tests to diagnose Helicobacter pylori infection in very young children

OBJECTIVE

To validate the (13)C-urea-breath-test (UBT) and stool antigen test (HpSA) in children aged 5 years or younger, against invasive histologic study and rapid-urease-testing or culture.

STUDY DESIGN

On all consecutive children aged 5 years or younger undergoing endoscopy in 1 single center during the last 7.5 years, UBT and HpSA were performed.

RESULTS

Of a total of 184 children (median age 2.2 years, range 0.2-5.5), 30 were Helicobacter pylori-positive (16.3%). Sensitivity and specificity of UBT were 93.3% (95%CI 77.9%-99.2%) and 95.5% (90.9-98.2), with a cutoff of 5 per thousand, but specificity increased to 98.1% (94.4%-99.6%) with a cutoff of 8 per thousand. Sensitivity and specificity of HpSA were 93.3% (77.9%-99.2%) and 98.7% (95.4%-99.8%).

CONCLUSION

Accuracy of noninvasive tests in our single-center study were satisfactory: specificity of UBT improved with a cutoff at 8%, and sensitivity of HpSA was high when determined locally without transportation after long or inadequate storage that could impair results.

Evaluation of four different fecal tests for determination of cure after Helicobacter pylori treatment

BACKGROUND

Data evaluating the monoclonal tests for determination of cure after Helicobacter pylori treatment are scarce.

GOALS

This study was aimed to evaluate the usefulness of 4 stool tests-2 new RAPID monoclonal immunochromatographic tests (RAPID Hp StAR, DakoCytomation, Cambridge, UK and ImmunoCard STAT! HpSA, Meridian Diagnostics, Cincinnati, OH) a monoclonal EIA test (Amplified IDEIA Hp StAR, DakoCytomation, Cambridge, UK), and a polyclonal EIA test (Premier Platinum HpSA, Meridian Diagnostics, Cincinnati, OH)-to confirm cure of H. pylori infection after eradication treatment.

STUDY

Ninety-seven patients who underwent eradication treatment were included. Cure of H. pylori infection was determined using 2 consecutive reference tests. Fecal tests were performed according to the specifications of the manufacturer. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

After H. pylori eradication, the RAPID Hp StAR test has a sensitivity of 73% for detecting persistent infection, a specificity of 96% to 98%, a positive predictive value of 73% to 80% and a negative predictive value of 96%. For ImmunoCard STAT! HpSA the corresponding values were 91%, 97%, 77%, and 99%, for Amplified IDEIA Hp StAR 73%, 97%, 73%, and 97%, and for Premier Platinum HpSA 91%, 79%, 35%, and 98%.

CONCLUSIONS

All tests except Premier Platinum HpSA were highly accurate confirming eradication after treatment.

The mother as source of Helicobacter pylori infection

BACKGROUND

To further elucidate the intrafamilial transmission of Helicobacter pylori infection, we investigated the occurrence of infection by parental infection status in a large community-based birth cohort of children from Germany.

METHODS

Parental infection (at birth) and children's infection (at age 3 years) were determined by C-urea breath test and by monoclonal antigen stool test.

RESULTS

Twenty of 834 children (2.4%) were found to be infected. The odds ratio for H. pylori infection of the child was 12.9 (95% confidence interval = 3.2-52.5) if the mother was infected and 1.4 (0.4-4.6) if the father was infected, after adjustment for infection status of the other parent and for nationality. The number of older siblings was not a risk factor for H. pylori infection of the child.

CONCLUSIONS

This longitudinal study suggests that infected mothers are the main source of H. pylori infection of their children.

Accuracy of monoclonal stool antigen test for the diagnosis of H. pylori infection: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of accuracy of monoclonal stool antigen test (SAT) for the diagnosis of Helicobacter pylori infection.

SELECTION OF STUDIES

assessing the accuracy of monoclonal SAT for the diagnosis of H. pylori infection.

SEARCH STRATEGY

electronic and manual bibliographical searches.

DATA EXTRACTION

independently done by two reviewers.

DATA SYNTHESIS

meta-analyses combining the sensitivities, specificities, and likelihood ratios (LRs) of the individual studies.

RESULTS

Twenty-two studies, including 2,499 patients, evaluated the monoclonal SAT before eradication therapy. Pooled sensitivity, specificity, LR+, and LR- were: 0.94 (95% CI 0.93-0.95), 0.97 (0.96-0.98), 24 (15-41), and 0.07 (0.04-0.12). The accuracy of both monoclonal and polyclonal SAT was evaluated together in 13 pretreatment studies, and higher pooled sensitivity was demonstrated with the monoclonal technique (0.95 vs 0.83). Twelve studies, including 957 patients, assessed the monoclonal SAT to confirm eradication after therapy. Pooled sensitivity, specificity, LR+, and LR- were 0.93 (0.89-0.96), 0.96 (0.94-0.97), 17 (12-23), and 0.1 (0.07-0.15). Both tests were evaluated together in eight post-treatment studies and, again, the monoclonal technique showed higher sensitivity (0.91 vs 0.76). Heterogeneity among studies disappeared when a single outlier study was excluded. Subanalysis depending on the reference method, the study population, or the study quality showed similar results.

CONCLUSION

Monoclonal SAT is an accurate noninvasive method both for the initial diagnosis of H. pylori infection and for the confirmation of its eradication after treatment. The monoclonal technique has higher sensitivity than the polyclonal one, especially in the post-treatment setting.