Serology and urea breath test in the diagnosis ofH. pylori infection

Helicobacter pylori is a chronic infection that has the potential for causing and initiating serious gastric-disease. Specific treatment can be successful in eradication of the infection but is currently complex which hampers essential patient compliance. Therefore, the accurate detection ofH. pylori and. importantly, the post-treatment check for cure is vital in the effective management of this infection. This is especially true in cases of asymptomatic individuals. Serology is now a simple ELISA with a high degree of accuracy and has been shown to be useful as a screening tool prior to endoscopy in selected cases. The urea breath test, either using C¹³ or C¹⁴. is a sensitive test easily applied and is the test of choice for post-treatment check for cure. It is also the gold standard for the validation of serology in different populations.     

An evaluation of a serologic test with a current infection marker of Helicobacter pylori before and after eradication therapy in Chinese

Background and Aims: Development of an accurate and less cumbersome noninvasive method to detect current Helicobacter pylori infection is essential in clinic. The aim of this study was to evaluate the performance of the CIM test, also known as the Assure®H. pylori Rapid Test (Genelabs Diagnostics Pty. Ltd., Singapore), for the diagnosis of current H. pylori infection before and after eradication therapy in Chinese population. Methods: A total of 452 eligible people were recruited for this study in Jiangsu Province, China. Each individual underwent a ¹³C urea breath test (¹³C‐UBT). For the evaluation of CIM test after eradication, 115 H. pylori‐positive outpatients were treated with 1‐week triple therapy. One month after the end of therapy, the patients underwent ¹³C‐UBT again, and the CIM‐test was performed 1, 3, and 6 months after the end of therapy. Its performance (sensitivity, specificity, positive and negative predictive values, and accuracy) were determined using the ¹³C‐UBT as a gold standard for H. pylori diagnosis. Results: H. pylori was detected in 221 (65.6%) of the 337 people by ¹³C‐UBT. The sensitivity, specificity, positive and negative predictive values, and accuracy of the CIM test were 93.2%, 90.5%, 94.9%, 87.5%, and 92.3%, respectively, using ¹³C‐UBT as a gold standard. One month after eradication therapy, the sensitivity, specificity of CIM test were only 50% and 66.7%, 66.7% and 84.6% 3‐month after eradication therapy and the sensitivity, specificity increased to 85.7% and 96.9%, respectively, when CIM test was used 6 months after the end of anti‐H. pylori therapy. Conclusions: The CIM test is a simple, rapid, accurate, cheap, and near‐people test. It may be satisfactory for detecting H. pylori infection in cases without eradication therapy, but it could not differentiate the past or current infection correctly within 6 months after anti‐H. pylori therapy.     

Review: Diagnosis of Helicobacter pylori infection

New imaging techniques are still the topic of many evaluations for both the diagnosis of Helicobacter pylori gastritis and the detection of early gastric cancer. Concerning invasive tests, there were studies on the reuse of the rapid urease test material for other tests, and a novel fluorescent method to be used for histology but with limited sensitivity. Progress occurred essentially in the molecular methods area, especially next‐generation sequencing which is applied to detect both H pylori and the mutations associated with antibiotic resistance. For non‐invasive tests, a few studies have been published on the validity of breath collection bags, the shortening of the testing time, the performance of different analysers or the added value of citric acid in the protocol. The accuracy of serological immunochromatographic tests is also improving. Multiplex serology detecting antibodies to certain proteins allows confirmation of a current infection. Dried blood spots can be used to collect and store blood without a loss of accuracy. Finally, the serum antibody titer can be useful in predicting the risk of gastric cancer. Several stool antigen tests were evaluated with good results, and a novel test using immunomagnetic beads coated with monoclonal antibodies is potentially interesting. PCR detection in stools can also be effective but needs an efficient DNA extraction method. The use of easyMAG^® (bioMérieux) combined with Amplidiag® H pylori + ClariR (Mobidiag) appears to be powerful.     

Diagnosis of Helicobacter pylori

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

休斯敦共识会议:关于美国幽门螺杆菌感染的检测

虽然,美国已有关于幽门螺杆菌(Helicobacter pylori,H.pylori)检测和治疗的指南,但对患者进行治疗前后H.pylori检测的建议通常没有得到遵循。来自美国不同地区研究成人和儿童H.pylori感染处理的11名专家参加了"休斯敦共识会议",并在会议中讨论诊断H.pylori感染的关键因素:确定目标人群进行H.pylori检测;抗生素药物敏感性对检测和治疗的影响;确认H.pylori感染和确认根除治疗结果的合适方法。专家被分为多组,采用改良的Delphi小组讨论法来评定需行H.pylori检测的目标人群,抗生素药物敏感性检测方法和治疗方法、根除治疗后的结果确认及相关检测方法。证据质量和建议强度均采用GRADE系统进行评估。各工作小组的结果将提交给所有小组成员进行最后的共识表决。在专家共识会议之后,这些结论将提交给一个独立的胃肠病学专家小组进行验证,并对会议中提出的29项声明进行认同程度评估。最后的建议是基于现有最佳证据提出,并提供带参考文献的共识声明,以便在全美各地的医疗保健体系中实施。     

Review: Diagnosis of Helicobacter pylori infection

Endoscopic imaging of the stomach is improving. In addition to narrow band imaging, other methods, for example, blue light imaging and linked color imaging, are now available and can be combined with artificial intelligence systems to obtain information on the gastric mucosa and detect early gastric cancer. Immunohistochemistry is only recommended as an ancillary stain in case of chronic active gastritis without Helicobacter pylori detection by standard staining, and recommendations to exclude false negative H. pylori results have been made. Molecular methods using real‐time PCR, droplet digital PCR, or amplification refractory mutation system PCR have shown a high accuracy, both for detecting H. pylori and for clarithromycin susceptibility testing, and can now be used in clinical practice for targeted therapy. The most reliable non‐invasive test remains the ¹³C‐urea breath test. Large data sets show that DOB values are higher in women and that the cut‐off for positivity could be decreased to 2.74 DOB. Stool antigen tests using monoclonal antibodies are widely used and may be a good alternative to UBT, particularly in countries with a high prevalence of H. pylori infection. Attempts to improve serology by looking at specific immunodominant antigens to distinguish current and past infection have been made. The interest of Gastropanel^® which also tests pepsinogen levels was confirmed.     

Inverse association between Helicobacter pylori and pediatric asthma in a high-prevalence population

Background: Helicobacter pylori‐associated disease has led to aggressive diagnostic and eradication protocols that are partially responsible for the decrease in prevalence of H. pylori carriage. Recent evidence indicates that in low‐prevalence populations, H. pylori may have protective effects on allergic diseases. The aim of this study was to explore the relationship between pediatric asthma and H. pylori infection in a population with high prevalence of H. pylori infection. Materials and Methods: A national referral laboratory was screened for all ¹³C urea breath tests performed in children aged 5–18 years between 2007 and 2008, for patient demographics and physician‐diagnosed asthma. Data concerning asthma‐associated medication usage were extracted from electronic medical records and databases. Data were analyzed using a stepwise logistic regression model. Results: During the study period, 6959 patients underwent urea breath testing (average age 12.4 ± 3.5 years). Of these, 3175/6959 (45.6%) were positive for H. pylori, and 578/6959 (8.3%) had asthma. Rates of asthma in H. pylori‐positive and H. pylori‐negative children were 7.3 and 9.1%, respectively (odds ratio 0.82; 95% confidence interval (CI) 0.69–0.98; p = .032). We also confirmed that male gender, urban residence, and age are associated with childhood asthma. Conclusions: We demonstrate an inverse association between H. pylori and pediatric asthma in a population with a high prevalence of H. pylori.     

Role of 13C-urea breath test in experimental model of Helicobacter pylori infection in mice

Background: Animal models have been widely used to study Helicobacter pylori infection. Evaluation of H. pylori infection status following experimental inoculation of mice usually requires euthanasia. The ¹³C‐urea breath test (¹³C‐UBT) is both sensitive and specific for detection of H. pylori in humans. Thus, it would be very useful to have such a test with the same accuracy for the follow‐up of this infection in animal models of gastric infection. Accordingly, the purpose of this study was to develop and evaluate a ¹³C‐UBT method for following the course of H. pylori infection in a mouse model. Material and Methods: A total of 50 female C57BL/6 mice were gavaged three times with either 10⁸ colony‐forming units of H. pylori (n = 29) or saline solution only (n = 21). After 2 months of infection, mice were fasted for 14 hours and ¹³C‐UBT was performed using 300 μg of ¹³C‐urea. The mice were killed, and the stomach was removed and processed for immunohistochemistry and PCR. Results: The optimal time for breath sample collection in mice was found to be 15 minutes. The ¹³C‐UBT cutoff was set at 3.0‰δPDB. Using PCR as the gold standard, the sensitivity of ¹³C‐UBT and immunohistochemistry was 96.6 and 72.4%, respectively, while the specificity was 85.7 and 95.2%, respectively. Conclusions: ¹³C‐UBT was shown to be a reliable method for the detection of H. pylori infection in C57BL/6 mice and was even more accurate than immunohistochemistry. The use of ¹³C‐UBT in the mouse model of H. pylori infection can be very useful to detect the bacterium without the need to kill the animals in long‐term time course studies.     

Evaluation of stool antigen test, PCR on ORAL samples and serology for the noninvasive detection of Helicobacter pylori infection in children

BACKGROUND: Endoscopy represents the gold standard for the diagnosis of Helicobacter pylori infection. We evaluated three noninvasive tests in a group of children: the immunoassay for detection of H. pylori stool antigen, the polimerase chain reaction for identification of bacterial DNA on the oral cavity and the serum specific antibodies. MATERIALS AND METHODS: One hundred and ninety children underwent endoscopy for various gastrointestinal symptoms. H. pylori stool antigen and anti-H. pylori antibodies were assayed by commercial kits. The bacterial DNA on saliva and oral plaque was detected by a seminested PCR. RESULTS: Based on the positivity of culture or urease rapid test and histology, infection was detected in 47 patients. The statistical analysis showed that, for the detection of the infection, stool antigen assay is more effective in sensitivity and negative predictive value (91.5% and 96.5%), whereas specificity and positive predictive values appear slightly better in serology (89.6% and 76.0%). Correlations between serum IgG both with patients' age (r = 0.21, p < .05) and H. pylori stool antigen (r = 0.47, p < .01) were found. The search for bacterial DNA on oral samples proved to be very specific (99.1% on saliva and 98.2% on plaque), but insensitive (22.2% and 25.7%). CONCLUSIONS. In children H. pylori stool antigen represents a sensitive test, suitable for detecting H. pylori infection. Serum IgG proved to be more specific; the PCR on the oral cavity resulted as being a very specific, but insensitive test.     

13C-urea breath test for the diagnosis of Helicobacter pylori infection in children: a systematic review and meta-analysis

Background: The ¹³C‐urea breath test (¹³C‐UBT) is a safe, noninvasive and reliable method for diagnosing H. pylori infection in adults. However, the test has shown variable accuracy in the pediatric population, especially in young children. We aimed to carry out a systematic review and meta‐analysis to evaluate the performance of the ¹³C‐UBT diagnostic test for H. pylori infection in children. Methods: We conducted a systematic review of the PubMed, Embase and Liliacs databases including studies from January 1998 to May 2009. Selection criteria included studies with at least 30 children and reporting the comparison of ¹³C‐UBT against a gold standard for H. pylori diagnosis. Thirty‐one articles and 135 studies were included for analysis. Children were stratified in subgroups of <6 and ≥6 years of age, and we considered variables such as type of meal, cutoff value, tracer dose, and delta time for the analysis. Discussion: The ¹³C‐UBT performance meta‐analyses showed 1, good accuracy in all ages combined (sensitivity 95.9%, specificity 95.7%, LR+ 17.4, LR? 0.06, diagnostic odds ratio (DOR) 424.9), 2, high accuracy in children >6 years (sensitivity 96.6%, specificity 97.7%, LR+ 42.6, LR? 0.04, DOR 1042.7), 3, greater variability in accuracy estimates and on average a few percentage points lower, particularly specificity, in children ≤6 years (sensitivity 95%, specificity 93.5%, LR+ 11.7, LR? 0.12, DOR 224.8). Therefore, the meta‐analysis shows that the ¹³C‐UBT test is less accurate for the diagnosis of H. pylori infection in young children, but adjusting cutoff value, pretest meal, and urea dose, this accuracy can be improved.     

Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti‐Helicobacter pylori IgG antibodies

Background

Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti‐ H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection.

Methods

A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti‐ H. pylori IgG antibodies; a UBT was administered to participants > 5 years old.

Results

We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti‐ H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age ≥ 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered.

Conclusions

Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity.