Noninvasive tests as a substitute for histology in the diagnosis of Helicobacter pylori infection

Accuracy of gastric nodule combined with rapid urease test prediction in diagnosing Helicobacter pylori infection in children

BACKGROUND

The diagnosis of Helicobacter pylori (H. pylori) infection in children remains challenging with the lack of a rapid, cost-effective, and highly accurate diagnostic method. Consequently, this study aimed to investigate the accuracy of the combination of gastric nodule and rapid urease test (RUT) as a diagnostic method for H. pylori infection in children.

METHODS

The study included participants who underwent a thorough examination, including gastroscopy, a 13C breath test, RUT, and pathological methylene blue staining, with the gold standard for diagnosing of H. pylori infection being a positive result from both pathological methylene blue staining and 13C breath test. The sensitivity, specificity, positive and negative predictive values, and accuracy of the diagnostic methods were calculated.

RESULTS

The accuracy of the different tests for H. pylori infection was evaluated in 2202 participants. A total of 730 (33.2%) children were diagnosed with H. pylori infection (pathological methylene blue staining and 13C breath test, both positive). Gastric nodule had a sensitivity of 87.1% and a specificity of 93.1%, whereas combining gastric nodule and RUT in parallel had the higher accuracy of 95.4%. The accuracy of gastric nodule diagnosis was higher in younger age groups and increased after excluding patients with a history of anti-H. pylori treatment.

CONCLUSIONS

The findings of this study suggest that gastric nodules, particularly when combined with RUT, can be a valuable predictor of H. pylori infection in children, offering a simple and feasible alternative to other invasive methods.

RE.GA.IN.: the Real-world Gastritis Initiative-updating the updates

At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.The most relevant topics related to the gastric inflammatory diseases have been addressed by the Real-world Gastritis Initiative (RE.GA.IN.), from disease definitions to the clinical diagnosis and prognosis. This paper reports the conclusions of the RE.GA.IN. consensus process, which culminated in Venice in November 2022 after more than 8 months of intense global scientific deliberations. A forum of gastritis scholars from five continents participated in the multidisciplinary RE.GA.IN. consensus. After lively debates on the most controversial aspects of the gastritis spectrum, the RE.GA.IN. Faculty amalgamated complementary knowledge to distil patient-centred, evidence-based statements to assist health professionals in their real-world clinical practice. The sections of this report focus on: the epidemiology of gastritis; Helicobacter pylori as dominant aetiology of environmental gastritis and as the most important determinant of the gastric oncogenetic field; the evolving knowledge on gastric autoimmunity; the clinicopathological relevance of gastric microbiota; the new diagnostic horizons of endoscopy; and the clinical priority of histologically reporting gastritis in terms of staging. The ultimate goal of RE.GA.IN. was and remains the promotion of further improvement in the clinical management of patients with gastritis.

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy

BACKGROUND

Helicobacter pylori (H. pylori) infection has been well-established as a significant risk factor for several gastrointestinal disorders. The urea breath test (UBT) has emerged as a leading non-invasive method for detecting H. pylori. Despite numerous studies confirming its substantial accuracy, the reliability of UBT results is often compromised by inherent limitations. These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H. pylori infection.

AIM

To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H. pylori infection in adult patients with dyspepsia.

METHODS

We conducted an independent search of the PubMed/MEDLINE, EMBASE, and Cochrane Central databases until April 2022. Our search included diagnostic accuracy studies that evaluated at least one of the index tests (13C-UBT or 14C-UBT) against a reference standard. We used the QUADAS-2 tool to assess the methodological quality of the studies. We utilized the bivariate random-effects model to calculate sensitivity, specificity, positive and negative test likelihood ratios (LR+ and LR-), as well as the diagnostic odds ratio (DOR), and their 95% confidence intervals. We conducted subgroup analyses based on urea dosing, time after urea administration, and assessment technique. To investigate a possible threshold effect, we conducted Spearman correlation analysis, and we generated summary receiver operating characteristic (SROC) curves to assess heterogeneity. Finally, we visually inspected a funnel plot and used Egger's test to evaluate publication bias.

RESULTS

The titles and abstracts of 4621 studies were screened; 79 articles were retrieved and selected for full-text reading. Finally, 60 studies were included in the diagnostic test accuracy meta-analysis. Our analysis demonstrates superior diagnostic accuracy of 13C-UBT over 14C-UBT, indicated by higher sensitivity (96.60% vs 96.15%), specificity (96.93% vs 89.84%), likelihood ratios (LR+ 22.00 vs 10.10; LR- 0.05 vs 0.06), and area under the curve (AUC; 0.979 vs 0.968). Notably, 13C-UBT's DOR (586.47) significantly outperforms 14C-UBT (DOR 226.50), making it the preferred diagnostic tool for dyspeptic individuals with H. pylori infection. Correlation analysis revealed no threshold effect (13C-UBT: r = 0.48; 14C-UBT: r = -0.01), and SROC curves showed consistent accuracy. Both 13C-UBT and 14C-UBT showed high AUC values (13C-UBT 0.979; 14C-UBT 0.968) near 1.00, reinforcing their excellent accuracy and endorsing both as reliable diagnostic tools in clinical practice.

CONCLUSION

In summary, our study has demonstrated that 13C-UBT has been found to outperform the 14C-UBT, making it the preferred diagnostic approach. Additionally, our results emphasize the significance of carefully considering urea dosage, assessment timing, and measurement techniques for both tests to enhance diagnostic precision. Nevertheless, it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

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.

Systematic Review and Meta-Analysis on the Sensitivity and Specificity of (13)C/(14)C-Urea Breath Tests in the Diagnosis of Helicobacter pylori Infection

Helicobacter pylori (H. pylori) continues to be a major health problem worldwide, causing considerable morbidity and mortality due to peptic ulcer disease and gastric cancer. The aim of the present systematic review and meta-analysis was to determine the sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection. A PRISMA systematic search appraisal and meta-analysis were conducted. A systematic literature search of PubMed, Web of Science, EMBASE, Scopus, and Google Scholar was conducted up to August 2022. Generic, methodological and statistical data were extracted from the eligible studies, which reported the sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection. A random effect meta-analysis was conducted on crude sensitivity and specificity of 13C/14C-urea breath test rates. Heterogeneity was assessed by Cochran’s Q and I2 tests. The literature search yielded a total of 5267 studies. Of them, 41 articles were included in the final analysis, with a sample size ranging from 50 to 21857. The sensitivity and specificity of 13C/14C-urea breath tests in the diagnosis of H. pylori infection ranged between 64−100% and 60.5−100%, respectively. The current meta-analysis showed that the sensitivity points of estimate were 92.5% and 87.6%, according to the fixed and random models, respectively. In addition, the specificity points of estimate were 89.9% and 84.8%, according to the fixed and random models, respectively. There was high heterogeneity among the studies (I2 = 98.128 and 98.516 for the sensitivity and specificity, respectively, p-value < 0.001). The 13C/14C-urea breath tests are highly sensitive and specific for the diagnosis of H. pylori infection.

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.

Link between Serum Pepsinogen Concentrations and Upper Gastrointestinal Endoscopic Findings

The serum pepsinogen (PG) assay findings are correlated with the status of Helicobacter pylori infection, but there are controversies on the link with upper gastrointestinal (UGI) endoscopic findings. The aim of this study was to determine the significance of a serum PG assay for correlating with endoscopic findings in H. pylori-seroprevalent adult population. Korean adults who visited for a health check-up were included consecutively. Subjects after gastrectomy or H. pylori eradication were excluded. After completing the serum PG assay and anti-H. pylori immunoglobulin G (IgG) titer on the same day of UGI endoscopy, subjects with equivocal serology test finding or gastric neoplasm were excluded. Of the 4,830 included subjects, 3,116 (64.5%) were seropositive for H. pylori. Seropositive finding was related to high serum PG I (P < 0.001) and PG II (P < 0.001) concentrations, low PG I/II ratio (P < 0.001), old age (P < 0.001), and male gender (P = 0.006). After adjusting age and gender, the serum PG I and II concentrations were positively correlated with the presence of nodular gastritis (NG) (all P = 0.003). The serum PG I was positively correlated with gastric ulcer (P = 0.003), and it was correlated with duodenal ulcer in seropositive subjects (P = 0.008). The PG I/II ratio was positively correlated with erosive esophagitis, while it was inversely related to chronic atrophic gastritis and metaplastic gastritis (all P < 0.001). Our findings suggest that the serum PG assay finding correlates well with the UGI endoscopic finding. A higher serum PG concentration in subjects with NG and peptic ulcer disease suggests that endoscopic findings reflect gastric secreting ability.

Herpes Simplex Virus Type 1 and Other Pathogens are Key Causative Factors in Sporadic Alzheimer's Disease

This review focuses on research in epidemiology, neuropathology, molecular biology, and genetics regarding the hypothesis that pathogens interact with susceptibility genes and are causative in sporadic Alzheimer's disease (AD). Sporadic AD is a complex multifactorial neurodegenerative disease with evidence indicating coexisting multi-pathogen and inflammatory etiologies. There are significant associations between AD and various pathogens, including Herpes simplex virus type 1 (HSV-1), Cytomegalovirus, and other Herpesviridae, Chlamydophila pneumoniae, spirochetes, Helicobacter pylori, and various periodontal pathogens. These pathogens are able to evade destruction by the host immune system, leading to persistent infection. Bacterial and viral DNA and RNA and bacterial ligands increase the expression of pro-inflammatory molecules and activate the innate and adaptive immune systems. Evidence demonstrates that pathogens directly and indirectly induce AD pathology, including amyloid-β (Aβ) accumulation, phosphorylation of tau protein, neuronal injury, and apoptosis. Chronic brain infection with HSV-1, Chlamydophila pneumoniae, and spirochetes results in complex processes that interact to cause a vicious cycle of uncontrolled neuroinflammation and neurodegeneration. Infections such as Cytomegalovirus, Helicobacter pylori, and periodontal pathogens induce production of systemic pro-inflammatory cytokines that may cross the blood-brain barrier to promote neurodegeneration. Pathogen-induced inflammation and central nervous system accumulation of Aβ damages the blood-brain barrier, which contributes to the pathophysiology of AD. Apolipoprotein E4 (ApoE4) enhances brain infiltration by pathogens including HSV-1 and Chlamydophila pneumoniae. ApoE4 is also associated with an increased pro-inflammatory response by the immune system. Potential antimicrobial treatments for AD are discussed, including the rationale for antiviral and antibiotic clinical trials.

Accuracy of urea breath test in Helicobacter pylori infection: Meta-analysis

AIM: To quantitatively summarize and appraise the available evidence of urea breath test (UBT) use to diagnose Helicobacter pylori (H. pylori) infection in patients with dyspepsia and provide pooled diagnostic accuracy measures.

METHODS: We searched MEDLINE, EMBASE, Cochrane library and other databases for studies addressing the value of UBT in the diagnosis of H. pylori infection. We included cross-sectional studies that evaluated the diagnostic accuracy of UBT in adult patients with dyspeptic symptoms. Risk of bias was assessed using QUADAS (Quality Assessment of Diagnostic Accuracy Studies)-2 tool. Diagnostic accuracy measures were pooled using the random-effects model. Subgroup analysis was conducted by UBT type (¹³C vs¹⁴C) and by measurement technique (Infrared spectrometry vs Isotope Ratio Mass Spectrometry).

RESULTS: Out of 1380 studies identified, only 23 met the eligibility criteria. Fourteen studies (61%) evaluated ¹³C UBT and 9 studies (39%) evaluated ¹⁴C UBT. There was significant variation in the type of reference standard tests used across studies.Pooled sensitivity was 0.96 (95%CI: 0.95-0.97) andpooled specificity was 0.93 (95%CI: 0.91-0.94). Likelihood ratio for a positive test was 12 and for a negative test was 0.05 with an area under thecurve of 0.985. Meta-analyses were associated with a significant statistical heterogeneity that remained unexplained after subgroup analysis. The included studies had a moderate risk of bias.

CONCLUSION: UBT has high diagnostic accuracy for detecting H. pylori infection in patients with dyspepsia. The reliability of diagnostic meta-analytic estimates however is limited by significant heterogeneity.

Accuracy of urea breath test performed immediately after emergency endoscopy in peptic ulcer bleeding

AIMS

The aim of this work is to investigate the accuracy of the urea breath test (UBT) performed immediately after emergency endoscopy in peptic ulcer bleeding (PUB).

METHODS

Urea breath test was carried out right after emergency endoscopy in patients with PUB. The accuracy of this early UBT was compared to a delayed one after hospital discharge that was considered the gold standard. Clinical and epidemiological factors were analyzed in order to study their influence on the accuracy of the early UBT.

RESULTS

Early UBT was collected without any complication and good acceptance from all the 74 patients included. In 53 of the patients (71.6%), a delayed UBT was obtained. Comparing concordance between the two tests we have calculated an accuracy of 83% for the early UBT. Sensibility and specificity were 86.36 and 66%, respectively, with a positive predictive value of 92.68% and negative predictive value of 50% (Kappa index = 0.468; p = 0.0005; CI: 95%). We found no influence of epidemiological factors, clinical presentation, drugs, times to gastroscopy, Forrest classification, endoscopic therapy, hemoglobin, and urea levels over the accuracy of early UBT.

CONCLUSIONS

Urea breath test carried out right after emergency endoscopy in PUB is an effective, safe, and easy-to-perform procedure. The accuracy of the test is not modified by clinical or epidemiological factors, ulcer stage, or by the type of therapy applied. However, we have found a low negative predictive value for early UBT, so a delayed test is mandatory for all negative cases.

Non-invasive testing for Helicobacter pylori in patients hospitalized with peptic ulcer hemorrhage: a cost-effectiveness analysis

PURPOSE

Guidelines recommend routine invasive screening for Helicobacter pylori in patients with peptic ulcer hemorrhage (PUH). However, compliance with screening remains suboptimal. The aim of this study was to determine if a simplified approach based on noninvasive screening is cost effective in PUH.

RESULTS

In the base case, post-endoscopy urea breath test (UBT) dominated the invasive testing with 34 fewer hemorrhages and cost savings of $406,600 in a cohort of 10,000 patients. When compliance with invasive testing decreases to 60%, post-endoscopy UBT leads to 109 fewer hemorrhages and cost savings of $1,089,600. The invasive strategy becomes the preferred choice if the sensitivity of UBT reduces to <75%, such as in patients taking proton-pump inhibitors (PPI) before hospitalization.

CONCLUSIONS

Post-endoscopy UBT is cost effective in PPI-naïve patients presenting with PUH. This strategy, once prospectively validated, can prove to be a preferred approach in institutions where compliance with invasive testing is suboptimal.

The Clinical Application of Ozonetherapy

The reader may be eager to examine in which diseases ozonetherapy can be proficiently used and she/he will be amazed by the versatility of this complementary approach (Table 9 1). The fact that the medical applications are numerous exposes the ozonetherapist to medical derision because superficial observers or sarcastic sceptics consider ozonetherapy as the modern panacea. This seems so because ozone, like oxygen, is a molecule able to act simultaneously on several blood components with different functions but, as we shall discuss, ozonetherapy is not a panacea. The ozone messengers ROS and LOPs can act either locally or systemically in practically all cells of an organism. In contrast to the dogma that “ozone is always toxic”, three decades of clinical experience, although mostly acquired in private clinics in millions of patients, have shown that ozone can act as a disinfectant, an oxygen donor, an immunomodulator, a paradoxical inducer of antioxidant enzymes, a metabolic enhancer, an inducer of endothelial nitric oxide synthase and possibly an activator of stem cells with consequent neovascularization and tissue reconstruction.

Endoscopic diagnoses and CLO test results in 9239 cases, prevalence of Helicobacter pylori in Istanbul, Turkey

BACKGROUND

Helicobacter pylori is implicated in the etiology of gastric and duodenal ulcer, non-ulcer dispepsia, atrophic gastritis, gastric adenocarcinoma and lymphoma.

METHODS

Between November 1995 and December 2004, the presence of H. pylori was investigated using the CLO test in 9239 patients who underwent upper gastrointestinal endoscopy at a single institution in Istanbul, Turkey. The results were evaluated as early-late positive, and negative.

RESULTS

There were 4667 women (50.51%) with a mean age of 44.5 years (range, 13-90 years), and 4572 men (49.49%) with a mean age of 45.7 years (range, 11-85 years). The CLO test was positive in 41.44% of cases. The most frequent symptoms on admission were epigastric pain (46.2%) and burning (19.6%). The most frequent endoscopic diagnosis was pangastritis (64%) and non-erosive duodenitis (30.5%). The H. pylori positivity was 61.53% during the first 5-year period and 38.47% during the second 5-year period. The H. pylori positivity was significant in patients using non-steroidal anti-inflamatory drugs and tobacco (P < 0.001).

DISCUSSION AND CONCLUSION

Helicbacter pylori prevelance remains an important health problem for Turkey although it has diminished in parallel to the national development during the last years. Helicbacter pylori, as a first-degree carcinogen, should be investigated and eradicated particularly in high-risk patients.

Immunoperoxidase in the interpretation of discordant histologic and urease findings for Helicobacter pylori

Azure A and methylene blue ("Diff-Quik," DQ) and tissue urease (U) tests are popular methods to diagnose Helicobacter pylori. These tests usually correlate well but sometimes produce discordant results. This study evaluates the DQ and U tests by comparing them with the immunoperoxidase reference method to resolve discordant results. DQ and U tests were performed on gastric biopsies. Results were tabulated as DQ(+)/U(+), DQ(+)/U(-), DQ(-)/U(+), and DQ(-)/U(-). Cases that were DQ(+)/U(+) were recorded as positive and not tested with immunoperoxidase. Cases that had discordant DQ/U results were tested by immunoperoxidase to resolve the discordance. Cases which were negative for both DQ/U were evaluated by immunoperoxidase to confirm the validity of DQ(1-)/U(-). The groups were compared with concordant results (DQ(1-)/U(-) group) and immunoperoxidase versus discordant DQ/U results and immunoperoxidase. There were 56 gastric biopsy specimens. Among all cases, 6 were DQ(+)/U(+). Of the remaining 50 cases, 38 were concordant DQ(-)/U(-), whereas 12 showed discordant DQ/U results. All 38 concordant DQ(-)/U(-) specimens were confirmed negative, 11 discordant DQ/U cases were confirmed negative, and 1 DQ(+)/U(-) specimen was confirmed positive by immunoperoxidase. Comparison of concordant versus discordant results was not statistically significant (P=0.10). Among all discordant DQ and U, 11/12 (92%) were confirmed negative by immunoperoxidase. Thus, both concordant negative results and discordant results can be considered negative. Such interpretation of discordant results might prevent unnecessary additional procedures or treatment.

Stool antigen testing for the diagnosis and confirmation of eradication of Helicobacter pylori infection: a prospective blinded trial

BACKGROUND AND AIMS

Helicobacter pylori is an established pathogen for a wide spectrum of gastroduodenal diseases. We investigated the usefulness of H. pylori stool antigen test (HpSA) before and after eradication therapy on patients referred for gastroscopy.

METHODS

Over a 12-month period, 127 adult patients (47% males) underwent HpSA and gastroscopy with dual biopsies from the antrum and proximal body of the stomach for urease and histology. The positive patients (histology, urease or combined positive) received triple therapy consisting of clarithromycin 500 mg, amoxycillin 1 g and omeprazole 20 mg, each given twice daily for 7 days. Six weeks post-therapy, eradication was verified with the 13C-urea breath test (UBT) and the HpSA results compared on a second stool sample.

RESULTS

Pre-therapy, 23/113 patients were positive by urease test, 22/112 by histology and 22/112 were combined positive. For the HpSA, compared to combined urease and histology as the reference standards, the sensitivity and specificity were 79 and 92% while the positive and negative predictive values (PPV and NPV) were 68 and 96%, respectively. Post-therapy, UBT was adopted as the reference standard and 18 paired samples were available for analysis: three were positive and 15 were negative. Sensitivity and specificity were 67 and 100% while the PPV and NPV were 100 and 94%, respectively.

CONCLUSIONS

In this prospective study, HpSA was found to be a reasonably useful diagnostic test for H. pylori infection. Post-eradication, it was highly specific and similar to UBT in terms of PPV and NPV. The test is non-invasive and cheaper than the urease test or the UBT, making it a candidate in the investigation of dyspepsia.

Helicobacter pylori and cagA gene detected by polymerase chain reaction in gastric biopsies: correlation with histological findings, proliferation and apoptosis

CONTEXT AND OBJECTIVE

The virulence of Helicobacter pylori (HP) in gastroduodenal disease is related to pathogenicity islands (cagPAI) present in some strains. Infection with cagPAI induces IL-8 secretion, increases epithelial cell proliferation and may be important in carcinogenesis. Our objective was to detect HP and the cagA gene (cagPAI marker) by polymerase chain reaction (PCR) and to correlate these results to histological findings, epithelial cell proliferation and apoptosis.

DESIGN AND SETTING

Retrospective, at the Surgical and Molecular Pathology Laboratory, Hospital Sírio-Libanês.

METHODS

DNA samples isolated from 164 gastric biopsies were used for HP detection by PCR. cagPAI+ was identified in HP+ cases by cagA gene amplification. All cases were submitted to immunohistochemistry to evaluate cell proliferation, and TUNEL to detect apoptosis. Statistical analysis was performed to compare results.

RESULTS

HP was detected in 67.7% of the patients, with good correlation between HP infection and moderate to severe gastritis, gastric ulcer and MALT lymphoma. There was a correlation between cagPAI+ strains and severe gastric diseases including cancer. The risk of gastric ulcer, adenocarcinoma and MALT lymphoma was 8.8 times higher for cagPAI+ patients. cagPAI+ infection was related to higher proliferation rates. The proliferation/apoptosis index was significantly higher for cagPAI+ patients.

CONCLUSION

Cell growth deregulation in cagPAI+ patients could be demonstrated by the difference in the proliferation index. We believe that this explains the carcinogenic role of Helicobacter pylori.

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Effectiveness of two quadruple, tetracycline- or clarithromycin-containing, second-line, Helicobacter pylori eradication therapies

BACKGROUND

There are no guidelines on second-line therapies for Helicobacter pylori eradication failures of omeprazole-clarithromycin-amoxicillin triple therapy.

AIM

To compare the efficacy of two second-line therapies for persistent H. pylori infection.

METHODS

Over a 6-year period, patients with persistent H. pylori infection following omeprazole-clarithromycin-amoxicillin eradication therapy were randomized to receive omeprazole, 20 mg twice daily, bismuth, 120 mg four times daily, metronidazole, 500 mg twice daily, and either tetracycline, 500 mg four times daily, or clarithromycin, 500 mg twice daily, given for 7 days. Before therapy, patients underwent endoscopy with biopsies for histology, culture and antibiotic susceptibility tests. H. pylori infection was confirmed by histology.

RESULTS

Of the 95 randomized patients, 88 (93%) completed the study. Age, sex, smoking, ulcer/non-ulcer dyspepsia ratio and antibiotic resistance were not significantly different between the treatment groups. On intention-to-treat analysis, eradication was achieved in 41 of the 49 patients (84%; 95% confidence interval, 70.4-92.7%) and 27 of the 46 patients (59%; 95% confidence interval, 43.3-73.0%) of the tetracycline- and clarithromycin-containing groups, respectively (P=0.007). On multivariate regression analysis, the sensitivity of H. pylori to metronidazole had a likelihood ratio of 5.2 (P=0.022), followed by the type of quadruple therapy (likelihood ratio, 4.4; P=0.036).

CONCLUSIONS

Tetracycline-containing quadruple rescue therapy is highly effective in treating H. pylori eradication failures of the omeprazole-amoxicillin-clarithromycin regimen.

The role of H pylori in gastrointestinal disease. A guide to identification and eradication

Helicobacter pylori, which is responsible for the most common infection worldwide, has been implicated in several gastrointestinal diseases, such as peptic ulcer disease, gastric adenocarcinoma, and mucosa-associated lymphoid tissue (MALT) lymphoma. In this article, Dr Knigge discusses the unique adaptation of H pylori to the acidic gastric environment and describes diagnostic tests to identify the organism, treatment recommendations, and tools to confirm eradication of infection.