Enzyme-linked immunosorbent assay for serodiagnosis of Helicobacter pylori in dyspeptic patients and volunteer blood donors

Helicobacter pylori, an important etiological agent in the development of gastritis, peptic ulcer and gastric carcinoma, can be detected by the enzyme-linked immunosorbent assay (ELISA). Our objectives were: (1) to evaluate the efficacy of a commercial ELISA kit (Pyloriset EIA-G III) in sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for diagnosis of H. pylori infection in Thai dyspeptic patients in Khon Kaen Thailand; and (2) to examine the seroprevalence of H. pylori among blood donors at Srinagarind Hospital's Blood Bank, Khon Kaen University, by the commercial ELISA. Gastric biopsies obtained from 137 dyspeptic patients were diagnosed by culture, rapid urease test (RUT) and histology. Serum samples from the same dyspeptic patients and 100 healthy blood donors were assayed using the commercial ELISA. H. pylori infection in dyspeptic patients was considered positive when the culture or both RUT and histology were positive. Using a cut-off value at a titer of 20 U/ml (as recommended by the manufacturer), we found the commercial ELISA kit had a sensitivity of 93.3%, specificity of 75.3%, PPV of 74.7%, NPV of 93.5% and accuracy of 83.2%. The overall H. pylori seroprevalence in the healthy blood donors was 57%. Of the 100 healthy blood donors, 39 (60.9%) of the males and 18 (50.0%) of the females were seropositive.     

A better method for confirming <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection in Mongolian gerbils

Background. Our aim was to evaluate the accuracy of the stool antigen test and the optimal time point for detecting Helicobacter pylori infection in a Mongolian gerbil model. Methods. We inoculated 8-week-old Mongolian gerbils with H. pylori (Vac A (+)/CagA(+)). The gerbil-infected model was developed as follows: H. pylori was put into broth (about 10⁹ CFU/ml), and 50 gerbils were then fed with 1 ml intragastrically twice within a 3-day interval. Another ten gerbils were fed broth only. Twenty-six weeks after the inoculation, the gerbils were killed. The gastric mucosa was sampled for a series of examinations including culture, histology, rapid urease test, and polymerase chain reaction. Stool samples for a stool antigen test, H. pylori-specific stool antigen assay (HpSA), were collected during weeks 4, 6, 8, 12, and 26 after inoculation. Of the 50 gerbils inoculated with H. pylori, the inoculation was successful in 88%. Severe active gastritis, ulceration, and intestinal metaplasia were obvious. Results. The HpSA test results were sensitivity, 88.6%; specificity, 100%; positive predictive value (PPV), 100%; negative predictive value (NPV), 54.5%, and accuracy, 90%. The HpSA test began to be more sensitive and accurate (P < 0.05) beginning during week 6 after inoculation. We also found that H. pylori could be detected earlier and more easily in the group with high H. pylori density. Conclusions. HpSA seems to be suitable for confirming colonization of gerbils with H. pylori. The optimal testing time point is around 6 weeks after inoculation. This test is a good choice for long-term observation of H. pylori infection in Mongolian gerbils.     

Optimizing the searching for H. pylori in clinical practice with EndoFasterⓇ

Background/AimH. pylori plays a major role in gastroduodenal diseases. Since its incidence is decreasing in developed countries, gastric biopsies were negative in several patients managed in clinical practice. We tested whether EndoFaster^Ⓡ − a device allowing real-time H. pylori detection by gastric juice analysis – may optimize the need of biopsies.MethodsIn this prospective, multicentre study, the accuracy of EndoFaster^Ⓡ for H. pylori detection was computed by using histology of gastric biopsies as a gold standard.ResultsData of 525 consecutive patients were available, including 90 (17.1%) patients with infection. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy of EndoFaster^Ⓡ were 87%, 84%, 53%, 97% and 85%, respectively. The overall accuracy of test was not affected neither by ongoing proton pump inhibitor therapy nor by previous eradication therapy. By using EndoFaster^Ⓡ in our series, biopsy sampling could have been eventually avoided in a total of 279 patients, accounting for a reduction of 42.3%, accepting the risk of only 8 false negative cases.ConclusionsThe very high NPV of EndoFaster^Ⓡ might allow to safely halve the need of taking gastric biopsies in unselected patients managed in clinical practice, avoiding an unavailing consume of health resources.     

Real-time determination of gastric juice pH with EndoFaster® for atrophic gastritis assessment

BackgroundIn patients with atrophic gastritis involving gastric body mucosa the pH value of gastric juice is distinctly increased, so that pH assessment would allow predict this precancerous lesion. We tested whether EndoFaster® ? a device allowing real-time pH measure and H. pylori diagnosis – may optimize the need of taking gastric biopsies.MethodsIn this prospective, multicentre study, the accuracy of EndoFaster® for ruling out gastric atrophy involving corporal mucosa was assessed. Real-time pH and ammonium determination was performed by aspirating 3–6 ml gastric juice during endoscopy. Histology performed on 5 standard gastric biopsies was used as gold standard.ResultsA total of 1008 consecutive patients were observed in 12 centres. At histology, gastric body mucosa atrophy/metaplasia was detected in 65 (6.4%) cases, and a pH value >4.5 in the gastric juice was observed in 150 patients. The values of EndoFaster® performance in predicting the presence of atrophic gastritis were as follow: 51% sensitivity, 84% specificity, 18% PPV, 96% NPV, and 82% accuracy. The NPV value was not distinctly affected by neither ongoing proton pump inhibitor therapy nor H. pylori infection. By considering also data of ammonium concentrations, the values of EndoFaster® in detecting extensive atrophy on gastric mucosa were 74% sensitivity, 84% specificity, 24% PPV, 98% NPV, and 83% accuracy.ConclusionThe very high NPV of EndoFaster® might allow to safely rule out presence of atrophic gastritis, reducing the need of taking gastric biopsies in unselected patients managed in clinical practice     

Validation of the 13c-urea breath test for the initial diagnosis of helicobacter pylori infection and to confirm eradication after treatment.

OBJECTIVES: the breath test with 13C-urea (UBT) is a method widely used in Spain, but its diagnostic accuracy has not been evaluated in a clinical trial until now. Our objective was to validate the UBT (TAU-KIT) both as an initial diagnostic method for the detection of H. pylori infection and as a method to confirm eradication. METHODS: a multi-centre study in 7 Spanish hospitals was performed. A group of dyspeptic patients who had not previously received eradication treatment was included, and a second group of patients with gastric ulcer or upper gastrointestinal bleeding due to peptic ulcer was also included (eradication of H. pylori was confirmed 6 to 8 weeks after treatment completion with omeprazole, clarithromycin and amoxycillin). In both groups an endoscopy was performed with biopsies for histology and rapid urease test. Patients were considered infected if both tests yielded positive results, and not infected when both tests were negative. The UBT 13C-urea (TAU-KIT, Isomed S.L., Madrid, Spain) was performed with citric acid and 100 mg of 13C-urea. The pathologist and persons responsible for endoscopy, urease test and UBT were all unaware of the results from the other diagnostic methods. RESULTS: in the pre-treatment group (36 patients) the prevalence of H. pylori was 72%, the area under the ROC curve for the diagnosis of infection with the UBT was 0.99, and the best cut-off point was 5 units, with the following results: sensitivity= 96% (95% CI = 81-99%), specificity= 100% (69-100%), positive predictive value (PPV) = 100% (87-100%), negative predictive value (NPV) = 92% (59-100%), likelihood ratio (LR) + = infinity, and LR- = 0.04. In the post-treatment group (85 patients) the prevalence of H. pylori was 16%, the area under the ROC curve was 0.99, and the best cut point was 4.6, with the following results: sensitivity= 100% (77-100%), specificity = 97% (90-99%), PPV = 88% (62-98%), NPV = 100% (95-100%), LR+ = 35, and LR- = 0. CONCLUSION: UBT provides excellent accuracy both for the initial diagnosis of H. pylori infection and to confirm eradication after treatment.     

The utility of intracystic glucose levels in differentiating mucinous from non-mucinous pancreatic cysts

BackgroundDifferentiating benign non-mucinous from potentially malignant mucinous pancreatic cysts is still a challenge. This study aims to improve this distinction with cyst fluid analysis.MethodsA cohort study of pancreatic cyst undergoing EUS/FNA was performed from a prospectively maintained database between 2014 and 2018 was performed.Results113 patients were analyzed (40 non-mucinous and 73 mucinous). For differentiating mucinous from non-mucinous cyst: intracyst glucose ≤41 mg/dl had a sensitivity of 92% and a specificity of 92%; positive predictive value (PPV) of 96 and negative predictive value (NPV) of 86. Glucose ≤21 mg/dl had a sensitivity of 88%, specificity of 97%, PPV of 98 and NPV of 81. CEA ≥192 ng/mL had a sensitivity of 50% and a specificity of 92%; PPV of 92 and NPV of 50. Glucose ≤21 mg/dl or CEA ≥192 ng/mL combined had a sensitivity of 93%, specificity of 92%, PPV of 96 and NPV of 87 (Fig. 1, Table 1).ConclusionIntra-cyst glucose levels (≤41 mg/dl) outperforms classic CEA testing for differentiation of mucinous from non-mucinous pancreatic cysts. It was found to be an excellent diagnostic test with an AUC of 0.95 (95% CI: 0.81, 0.97).     

Diagnosis of Helicobacter pylori infection by stool antigen determination: a systematic review

Recently a new, noninvasive diagnostic test based on the detection of Helicobacter pylori stool antigen (SA) has been developed. The aim of this study was to systematically review the experience on H. pylori SA test for the diagnosis of H. pylori infection. Bibliographic searches were performed in the PubMed database and abstracts from several congresses. A total of 43 studies fulfilled the inclusion criteria and evaluated H. pylori SA test accuracy for the diagnosis of H. pylori infection in nontreated patients. Overall, 4769 patients were included. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) (weighted mean) were, respectively: 92.4% (95% CI = 91-93%), 91.9% (91-92%), 92.1% (91-93%), and 90.5% (90-91%). Therefore the SA test can definitively be considered an accurate noninvasive method for the diagnosis of H. pylori infection in untreated patients. A total of 25 studies including 2078 patients evaluated H. pylori SA test for the confirmation of H. pylori eradication > or = 4 wk after completion of therapy. Sensitivity, specificity, PPV and NPV (weighted mean) were: 88.3% (87-90%), 92% (91-93%), 75.1% (73-77%), and 94.8% (94-96%). Although most studies showed that SA test is an accurate method to confirm H. pylori eradication > or = 4 wk after treatment, these favorable results were not confirmed in other studies. Further investigation is necessary to explain these discrepancies, as well as to clarify the precise time for confirmation of eradication after therapy, the appropriate cutoff point for the SA test, and which factors influence it. Proton pump inhibitors seem to affect the accuracy of SA test, but the negative effect disappears 1-2 wk after stopping treatment. The SA test is technically feasible in patients with upper GI bleeding. although the true diagnostic accuracy in this group of patients remains to be more fully assessed. Finally, the SA test seems to be a highly cost-effective method for the diagnosis of H. pylori infection.     

Relevance of Adjusted Cut-off Values in Commercial Serological Immunoassays for Helicobacter pylori Infection in Children

We assessed the sensitivity and specificity of H. pylori IgG and IgA with a commercial immunoassay performed in Chile and a second non-commercial immunoassay performed in a reference laboratory in the United States, in serum of 80 children and adults referred for gastrointestinal endoscopies in a developing country. Overall, 56% of the patients were infected with H. pylori based on rapid urease test and staining techniques on gastric biopsies. When Receiver Operator Curves (ROC) were developed, the sensitivity and specificity were similar for IgG and IgA. Both immunoassays exhibited better specificity, positive and negative predictive value (NPV) in children than in adults when cut-off values were corrected according to the local population than when they were assessed using the cut-off values pre-defined in other populations. These results underline the need to establish more precise cut-off values corrected in the local populations where assessments of antibodies as diagnostic markers of H. pylori infection are planning.     

Managing dyspepsia in the young adult patient: effects of different tests for Helicobacter pylori in a “test-and-scope” approach

Abstract

Aim. To evaluate how different methods for the detection of Helicobacter pylori influence on a “test, score and scope” decision approach in young dyspeptic patients. Results. Complete data from 341 patients (52.2% males) were analyzed. One hundred and ten (32%) were H. pylori-positive by definition. The rapid serology test was true-positive in 64 patients, false-positive in 8, and false-negative in 46. For the EIA IgG serology test, the corresponding results were 99 true-positive, 7 false-positive, and 11 false-negative. If the H. pylori fecal test or urea breath test had been applied, 108 (98%) and 107 (97%) positives would have been correctly detected, respectively, as well as 14 and 7 false positives. Models using test data in a setting of decreasing H. pylori prevalence show that test properties have increasing significance. Conclusions. In a selection strategy for young dyspeptics based on the detection of H. pylori, the choice of test should be made with caution. H. pylori fecal test would probably give the best basis for such selection.     

A close relationship between Helicobacter pylori infection and the serum level of CD47 in adults

Abstract

Objectives: Although Helicobacter pylori (H. pylori) infection is one of the most important risk factors for gastric cancer, the molecular mechanisms underlying the progression of H. pylori-induced gastric cancer remain unclear. Previous studies have demonstrated that Integrin-associated protein (CD47) plays an important role in the development of gastric cancer. Hence, the aim of this study was to preliminarily explore the relationship between CD47 and H. pylori infection.

Methods: A total of 417 adults who underwent health checkups at a hospital were recruited in 2018. Serum levels of CD47 and tumor necrosis factor-α (TNF-α) were determined using an enzyme-linked immunosorbent assay. ¹³C urea breath test (¹³C-UBT) was carried out to diagnose H. pylori infection in all participants.

Results: Compared with H. pylori-negative participants, H. pylori-positive participants have higher levels of serum CD47 and TNF-α. H. pylori infection, the levels of serum TNF-α and low density lipoprotein (LDL) are the independent predictors of serum level of CD47 in adults. In addition, a potential diagnostic value of serum CD47 level for H. pylori infection has been demonstrated in our study.

Conclusion: H. pylori infection is closely associated with the serum level of CD47 in adults, suggesting that H. pylori may promote gastric cancer progression by activating CD47-mediated oncogenic pathways.     

Accuracy of Seven Different Tests for the Diagnosis of Helicobacter pylori Infection and the Impact of H2-Receptor Antagonists on Test Results

Background: In this study we compared the accuracy of seven diagnostic tests in diagnosing Helicobacter pylori infection. Methods: Over 1 year 351 consecutive dyspeptic patients were tested for H. pylori infection by means of antral biopsy specimens for the rapid urease test (RUT), culture, microscopy (acridine stain), and the laboratory urease test (LUT) and, in addition, with ¹⁴C urea breath test (UBT), IgG serology, and IgA serology (Orion Diagnostica Pyloriset New EIA-G and New EIA-A). The criterion for H. pylori infection was a minimum of three positive tests. Before being tested, 38% of the patients had used an H₂-receptor antagonist (H₂RA). Results: Two-hundred and twenty-four patients (64%) were H. pylori-positive. The sensitivity and specificity of the tests were as follows (percentages): RUT, 85, 99; culture, 93, 100; microscopy, 81, 98; LUT, 80, 100; UBT, 95, 95; IgG serology, 99, 91; and IgA serology, 88, 91. The accuracy of the RUT and LUT was reduced in patients receiving HRA therapy (P = 0.04 and 0.01, respectively). Conclusions: Culture, UBT, and IgG serology were all superior to the other four tests in diagnosing H. pylori infection. Invasive urease-based tests were less accurate in patients receiving HRAs.     

Application of convolutional neural networks for evaluating Helicobacter pylori infection status on the basis of endoscopic images

Background and aim: We recently reported the role of artificial intelligence in the diagnosis of Helicobacter pylori (H. pylori) gastritis on the basis of endoscopic images. However, that study included only H. pylori-positive and -negative patients, excluding patients after H. pylori-eradication. In this study, we constructed a convolutional neural network (CNN) and evaluated its ability to ascertain all H. pylori infection statuses.

Methods: A deep CNN was pre-trained and fine-tuned on a dataset of 98,564 endoscopic images from 5236 patients (742 H. pylori-positive, 3649 -negative, and 845 -eradicated). A separate test data set (23,699 images from 847 patients; 70 positive, 493 negative, and 284 eradicated) was evaluated by the CNN.

Results: The trained CNN outputs a continuous number between 0 and 1 as the probability index for H. pylori infection status per image (Pp, H. pylori-positive; Pn, negative; Pe, eradicated). The most probable (largest number) of the three infectious statuses was selected as the ‘CNN diagnosis’. Among 23,699 images, the CNN diagnosed 418 images as positive, 23,034 as negative, and 247 as eradicated. Because of the large number of H. pylori negative findings, the probability of H. pylori-negative was artificially re-defined as Pn ?0.9, after which 80% (465/582) of negative diagnoses were accurate, 84% (147/174) eradicated, and 48% (44/91) positive. The time needed to diagnose 23,699 images was 261?seconds.

Conclusion: We used a novel algorithm to construct a CNN for diagnosing H. pylori infection status on the basis of endoscopic images very quickly.

Abbreviations: H. pylori: Helicobacter pylori; CNN: convolutional neural network; AI: artificial intelligence; EGD: esophagogastroduodenoscopies.     

Comparative evaluation of urine-based and other minimally invasive methods for the diagnosis of Helicobacter pylori infection

Background: Diagnostic methods have recently been developed for detecting anti-Helicobacter pylori antibody in urine and H. pylori antigen in stool samples. Our aim was to evaluate the usefulness of noninvasive urine-based methods for the diagnosis of H. pylori infection. Methods: The study subjects were 100 asymptomatic Japanese volunteers. We investigated the diagnostic efficacy of various noninvasive diagnostic methods; five serological tests (Immunis anti-pylori, HM-CAP, EIAgen Helicobacter pylori IgG, Helico G, and GAP-IgG), one test for antigen in stool (HpSA enzyme immunoassay [EIA]), and two tests for antibody in urine (Urinelisa and Rapirun) by using the urea breath test (UBT) as the gold standard. Results: Fifty subjects were diagnosed as positive for H. pylori infection by the UBT. The serological tests showed good sensitivity, specificity, and accuracy. The diagnostic values of the feces-based test (HpSA EIA) were lower than that of the serological tests. The sensitivities of the two urine-based methods in frozen urine samples were markedly lower than those of the other tests. However, the use of unfrozen samples markedly improved the diagnostic accuracy of these urine-based tests, which was then superior to that of the feces-based method. Conclusions: This study clearly showed that urine-based tests were useful for the diagnosis of H. pylori infection. However, the use of frozen urine samples was not appropriate for the detection of anti-H. pylori antibody. Received: November 5, 2001 / Accepted: February 22, 2002 Acknowledgments. We wish to thank Ms. Rika Tohma, Ms. Shiho Yamamoto, Ms. Yukiko Inoue, Mr. Masahiro Ishibashi, and Mr. Nobuo Sasaki for their technical supports. This work was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan. Reprint requests to: K. Adachi     

~(13)C-尿素呼气试验诊断幽门螺杆菌感染的研究

本研究旨在评估~(13)C,尿素呼气试验检测幽门螺杆菌感染的可靠性。方法:我们在82例因胃病而行胃镜检查的患者胃窦和胃体取多个活检标本,作组织学、牯膜涂片和快速尿素酶试验,以决定是否感染幽门螺杆菌,并作~(13)C-尿素呼气试验。~(13)C-尿素呼气试验的敏感性、特异性、阳性预测值、阴性预测值是与组织学和尿素酶方法检测幽门螺杆菌的结果比较而计算得到。结果:~(13)C-尿素呼气试验的敏感性97.92％,特异性100％,阳性预测值100％,阴性预测值97.14％,准确性98.78％。结论:~(13)C-尿素呼气试验有高度敏感性和特异性,对确定患者的幽门螺杆菌感染状态是一可靠的无创伤的诊断方法。     

The CLO test is unreliable in diagnosing H. pylori infection in post-surgical stomach; is there any role of H. pylori in peptic ulcer recurrence?

AIM: To evaluate the validity of the CLO test in detecting Helicobacter pylori in patients with gastric operation and to investigate the relationship of H. pylori with peptic ulcer recurrence in these patients. METHODS: In this prospective study, 110 consecutive patients, the majority of whom had undergone gastric operation for benign disease (n = 102), were included. Eighty patients (62 males), aged 38-87 years, had had a gastrectomy (10 Billroth I, 70 Billroth II), and 30 patients (27 males), aged 36-73 years, had had a vagotomy (13 vagotomy plus gastroenterostomy, 17 vagotomy plus pyloroplasty). H. pylori was sought on multiple biopsy specimens, using CLO test and histology (modified Giemsa stain). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the CLO test were estimated using histology as 'gold standard'. RESULTS: Overall, 21 gastrectomy patients (26%) were H. pylori-positive by CLO and 25 (31 %) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test, using histology as 'gold standard', were 68%, 91%, 77% and 86%, respectively. The CLO test was positive in 67% of vagotomy patients (20 of 30), while 50% (15 of 30) were H. pylori-positive by histology. The estimated sensitivity, specificity, PPV and NPV of the CLO test were 87%, 53%, 65% and 80%, respectively. H. pylori prevalence by histology was 50% in patients with vagotomy and 31% in those with gastrectomy (P = 0.0787). Recurrent ulcers were observed in 8/30 patients (27%) after vagotomy and in 10/72 patients (14%) after gastrectomy. Recurrent ulcer was documented in 6/15 H. pylori-positive patients with vagotomy (40%), and in one of 25 H. pylori-positive patients with gastrectomy (4%). This difference was significant (Fisher's exact test, P = 0.007, relative risk 5.091, 95% CI 0.819-31.64). CONCLUSION: The CLO test seems to be unreliable in diagnosing H. pylori in post-surgical stomach. The H. pylori prevalence is higher, although not significantly, in vagotomized patients compared with gastrectomized patients, and in this group is closely related to the presence of recurrent ulcer. So, at least in this group of patients, it is strongly recommended to look for and eradicate H. pylori.     

Low Incidence of Helicobacter pylori Infection in Patients with Duodenal Ulcer and Chronic Liver Disease

Background: Duodenal ulcer (DU) is a common problem in patients with chronic liver disease (CLD) and with inadequate response to H2 receptor antagonists. Omeprazole might be more effective. In DU-CLD patients, Helicobacter pylori prevalence is low. Nitric oxide is increased in gastric mucosa in cirrhosis. Oxygen-free radicals have a role in gastric inflammation and are abnormal in CLD. Nitrotyrosine is a marker of nitric oxide and oxygen-free radical toxic mucosal reaction. Methods: Sixtynine patients were divided into 2 groups: control (26 patients with DU) and CLD groups (43 patients, DUCLD). Omeprazole was given (40 mg/day) for 2 or 4 weeks. Symptoms and endoscopy findings were recorded before and after treatment. Antral biopsy specimens were stained for H. pylori and nitrotyrosine. Results: Clinical features of DU are similar in patients with and without CLD. The main presentation was epigastric pain (70%) and bleeding (23%). Healing rate with omeprazole was higher in DU-CLD patients (90.7%) than in controls (80.8%). H. pylori was much lower in DU-CLD patients (51.2%) than controls (96.2%). Nitrotyrosine staining was negative in normal controls (0%) and positive in control-DU (100%), CLD- H. pylori positive (81%), and CLD-H. pylori negative (91%) cases. Conclusions: DU in patients with CLD is not different clinically from those without CLD. Omeprazole effectively and safely treats DU in CLD. Nitric oxide and free oxygen radicals may result in gastric mucosal changes in CLD similar to that caused by H. pylori.     

Non-invasive diagnosis of H pylori infection： Evaluation of serological tests with and without current infection marker CIM

AIM： TO evaluate the performance of commercially available immunochromatographic （ICT） and immunoblot tests covering the current infection marker CIM and conventional ELISA for the diagnosis of Hpylori infection in adult dyspeptic patients.
METHODS： Consecutive non-treated dyspeptic patients undergoing diagnostic endoscopy were tested for H pylori infection by culture, rapid urease test, and histology of gastric biopsy specimens. Serum from 61 H pylori infected and 21 non-infected patients were tested for anti-H pylori IgG antibodies by commercial ELISA （AccuBindTM ELISA, Monobind, USA）, ICT （Assure H pylori Rapid Test, Genelabs Diagnostics, Singapore）, and immunoblot （Helico Blot 2.1, Genelabs Diagnostics, Singapore） assays. ICT and immunoblot kits cover CIM among other parameters and their performance with and without CIM was evaluated separately.
RESULTS： Sensitivity, specificity, positive predictive value （PPV）, negative predictive value （NPV）, and accuracy of ELISA were 96.7%, 42.8%, 83.1%, 81.8%, and 82.9%, of ICT were 90.1%, 80.9%, 93.2%, 73.9%, and 87.8%, of ICT with CIM were 88.5%, 90.4%, 96.4%, 73.0%, and 89.0%, of immunoblot were 98.3%, 80.9%, 93.7%, 94.4%, and 93.9%, and of immunoblot with CIM were 98.3%, 90.4%, 96.7%, 95.0%, and 96.3%, respectively.
CONCLUSION： Immunoblot with CIM had the best performance, ICT with CIM was found to be more specific and accurate than the conventional ELISA and may be useful for non-invasive diagnosis of Hpylori infection.     

Helicobacter pylori and Bleeding Duodenal Ulcer: Prevalence of the Infection and Role of Non-steroidal Anti-inflammatory Drugs

Background: Several authors have reported low prevalence of Helicobacter pylori infection in patients with upper gastrointestinal bleeding (UGIB). Our aim was to study the prevalence of H. pylori in bleeding duodenal ulcer (DU), with both invasive and non-invasive methods, and to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs). Methods: Ninety-two patients with bleeding DU were prospectively studied. The use of NSAIDs was evaluated by specific questionnaire. As a control group, 428 patients undergoing outpatient evaluation for the investigation of dyspepsia and found to have a DU at endoscopy were included. At endoscopy, two antral biopsies were obtained (H&E stain). A 13C-urea breath test was carried out in all patients. Breath test was repeated in patients treated with omeprazole during the hospitalization if H. pylori was not detected with the first test. Results: Gastric biopsies could be obtained in 39 patients with UGIB. Three patients with UGIB treated with omeprazole and being H. pylori negative with the first breath test were finally considered infected with the second test. Overall, 92.4% (95% CI, 85%-96%) of the patients with UGIB were infected (89.7% with histology and 92.4% with breath test (P = 0.15)). Concordance kappa value for both diagnostic tests was 0.64. NSAID intake was more frequent in patients with UGIB (34%) than in those without UGIB (5.6%) (P &lt; 0.001), while H. pylori infection was less frequent in patients with UGIB (92.4% (85%-96%)) than in those without UGIB (99.1% (98%-100%); P &lt; 0.001). Even in patients with UGIB, NSAID intake was the only risk factor in 5% of cases. The proportion of cases without H. pylori infection and without NSAID intake was very low in both bleeding and non-bleeding ulcers (2% and 0.5%, respectively; P = 0.146). H. pylori prevalence in bleeding ulcers was of 84% (67%-93%) in patients with NSAID intake, and 96.7% (89%-99%) when patients taking NSAIDs were excluded. In the multivariate analysis, NSAID intake (odds ratio, 9.8 (5.2-18.4)) correlated with UGIB; however, neither H. pylori status nor the interaction between H. pylori infection and NSAID intake correlated with UGIB. In the multivariate analysis in the subgroup of patients with UGIB, NSAID use was the only variable which correlated with H. pylori prevalence (odds ratio, 0.18 (0.03-0.97)). Conclusions: The most important factor associated with H. pylori-negative bleeding DU is NSAID use, and if this factor is excluded prevalence of infection is almost 100% (97%), similar to that found in patients with non-bleeding DU (and without NSAID intake). Bleeding DU patients with neither H. pylori infection nor NSAID use are extremely rare (only 2%), which suggests that the pathogenesis of bleeding DU is similar to that of non-complicated DU disease.     

Prevalence and risk factors for upper gastrointestinal diseases in health check-up subjects: a nationwide multicenter study in Korea

Objectives: The prevalence of upper gastrointestinal disease is expected to change following advances in socioeconomic status and improved hygiene in Korea. The aim of this study was to investigate the recent trends in upper gastrointestinal diseases based on endoscopic findings and Helicobacter pylori (H. pylori) seroprevalence in subjects undergoing health check-up at tertiary centers in Korea.

Methods: A multicenter cross-sectional study was conducted at nine healthcare centers between September 2016 and June 2017. The subjects were evaluated using questionnaires, upper endoscopy and H. pylori serology tests. The results were compared with previous data in our study group obtained from eight tertiary healthcare centers in 2011 (n?=?4023).

Results: In total, we prospectively enrolled 2504 subjects undergoing health check-up. The prevalence of reflux esophagitis (RE) was 9.7%, which showed an increasing but insignificant trend since 2011 (8.8%). The prevalence of active and healing-stage benign gastric ulcer and duodenal ulcer (DU) was 1.6% and 1.2%, respectively, which confirmed a significant decrease since 2011 (4.1%; p?p?=?.005, respectively). The prevalence of gastric cancer was 0.5%, representing an increasing trend since 2011 (0.12%; p?=?.003). H. pylori seroprevalence was 51.3%, which significantly decreased from 2011 (59.8%; p?H. pylori seropositivity was a significant risk factor for DU (p?p?Conclusions: The significant decrease of H. pylori seroprevalence in the past five years altered the incidence of upper gastrointestinal disease.     

Isolation and diagnosis of Helicobacter pylori by a new method: Microcapillary culture

AIM:To investigate the performance of the microcapillary culture method(MCM) in Helicobacter pylori(H.pylori) isolation and diagnosis.METHODS:Microcapillary culture(MC),classical culture(CC),rapid urease(CLO) test,and histopathologic examination(HE) were performed with biopsy samples.Homogenized biopsy samples were loaded into capillary tubes and incubated for 48 h at 37 ℃ without providing a microaerophilic environment.Additionally,three or four loops of the homogenized sample were inoculated in a ready-to-use selective medium(Becton Dickinson,Helicobacter Agar,Modified) specific for the isolation of H.pylori and incubated at 37 ℃ in a microaerophilic atmosphere provided by Campy Gen(Becton Dickinson,Gas Pack).Bacteria reproducing in microcapillary tubes were evaluated in an inverted microscope and also were evaluated after performing a CC with the content.Results obtained by CC,CLO test,and HE were compared with those of MC.The diagnostic performances of the methods used in this study were evaluated for specificity,sensitivity,positive predictive value(PPV),negative predictive value(NPV),and CI.RESULTS:H.pylori was found positive by CLO test +HE and/or CC culture in 26 patient antrum and corpus biopsy samples.In 25(25/26) patient biopsy samples,H.pylori was isolated by MCM,whereas in only 14(14/26) patient biopsy samples,H.pylori was isolatedby CC.CLO test and HE were found positive in 17(17/26) patient biopsy samples.Comparing the results of the isolation of H.pylori by MCM,CC,CLO test,and HE,the sensitivity of the MCM was found as 96%,the specificity as 80%,the PPV as 83%,the NPV as 95%,and the 95%CI as 0.76(χ2 =31.51,P < 0.01) whereas the sensitivity of the CC was found as 54%(χ2 =19.15,P < 0.01),and the sensitivity of the CLO test and HE were found as 65%(χ2 =25.26,P < 0.01).CONCLUSION:This new microcapillary cultivation method for H.pylori has high diagnostic sensitivity compared with CC,HE,and CLO tests.