Detection of Helicobacter pylori DNA in gastric juice by the polymerase chain reaction: comparison with findings in bacterial culture and the detection of tissue IgA and serum IgG antibodies against Helicobacter pylori

13C-Urea Breath Test for the Diagnosis of H. pylori Infection in Patients after Partial Gastrectomy: A Systematic Review and Meta-Analysis

BACKGROUND

The ¹³C-urea breath test (¹³C-UBT) is a kind of safe, noninvasive, and reliable measure for Helicobacter pylori (H. pylori) infection diagnosis in patients with complete stomach. Nevertheless, the test has not indicated fully precision in people who have had a gastrectomy. So, we made the use of a systematic review of plentiful published resources and research and meta-analysis. There are prominent research achievements regarding of utilizing ¹³C-UBT for H. pylori infection patients diagnosis with the residual stomach.

METHOD

We searched publications available on Cochrane, PubMed, and Embase databases, and on the web of science. The last search was performed in May 2021. The basis model for this meta-analysis was fixed-effect through Metadisc Beta 1.4 software (Universidad Complutense, Madrid, Spain). When measuring the precision of ¹³C-urea breath test, we utilized the ratio analysis such as Ratio of diagnostic odds ratio (DOR) and its corresponding 95% confidence interval (95%CI).

RESULTS

Ten associated researches were analyzed with a total of 1065 patients. In general, the sensitivity of included studies ranged from 0.40 to 1.00 (I² = 81.2%), whereas the specificity ranged from 0.59 to 1.00 (I² = 90.1%). The pooled sensitivity, specificity were 0.83 (95% CI, 0.79-0.86; P < 0.001), 0.79 (95% CI, 0.76-0.83; P < 0.001) respectively. The accuracy ranged from 71 to 99. The positive predictive values ranged from 45 to 100. The negative predictive values ranged from 53 to 100. The combined DOR was 36.02 (95%CI 15.65-82.92; I² = 65.8%; P = 0.0018). The corresponding AUC for the SROC curve was 0.92 and the Q value was 0.85.

CONCLUSION

In conclusion, the outcomes of meta-analysis indicate that during the period of patients' diagnosis in H. pylori infection, who undergoes partial gastrectomy, has high accuracy.

Pharmacokinetics of single and repeated oral doses of esomeprazole and gastrin elevation in healthy males and females

OBJECTIVE

Gastrin elevation secondary to proton pump inhibitor (PPI) therapy is well documented. Recent studies have demonstrated a sex-related difference where females on PPIs have significantly higher baseline gastrin levels than males. The aim of the study was to analyse the pharmacokinetics of esomeprazole and short-term effect on serum gastrin levels and evaluate potential sex-related difference.

MATERIALS AND METHODS

Healthy volunteers received 40 mg of esomeprazole daily for five days. After the 1st and 5th dose blood samples for fasting gastrin and pharmacokinetic analysis were collected at scheduled time-points for eight hours. Esomeprazole was analysed by liquid chromatography and gastrin concentrations were measured using radioimmunoassay.

RESULTS

A total of 30 volunteers were enrolled. Females had higher median baseline gastrin (pM) than males 12 (IQR 10-15) vs. 7 (IQR 4-11) (p = .03). In the study cohort, median gastrin levels rose from 10 (IQR 6-14) to 15 (IQR 13-20) (p = .0002). The serum levels for esomeprazole increased by an average of 299.8 ng/mL (p < .001) from day 1 to day 5. Comparison of the esomeprazole pharmacokinetic parameters between males and females revealed no significant sex-related differences. No significant correlation was found between the AUC and the gastrin level on day 5 (p = .15).

CONCLUSIONS

In healthy volunteers, serum gastrin increased significantly after a four-day PPI-therapy. There was also a significant increase in serum esomeprazole from day 1 to day 5. The increase in gastrin and esomeprazole concentration was not related to sex and no significant sex-related difference was found in terms of pharmacokinetic parameters. European Clinical Trial Database (2015-002230-41).

Predictors of Gastrin Elevation Following Proton Pump Inhibitor Therapy

GOALS

The goal of this study was to elucidate the most important predictors for elevation of gastrin in patients on long-term PPI therapy through analysis of data from 2 published studies in Icelandic patients with erosive GERD.

BACKGROUND

Gastrin elevation is a known but variable consequence of proton pump inhibitor (PPI) therapy. Concerns have been raised about the clinical importance of chronic PPI induced gastrin elevation.

STUDY

This cross-sectional analysis included patients with endoscopically verified erosive esophagitis receiving long-term PPI therapy. PPI exposure in dosage over weight (mg/kg) and dosage over body surface area (mg/m) was compared with fasting gastrin levels in two separate multiple linear regression models. Data was collected on age, gender, weight, H. pylori infection, smoking, PPI duration and type.

RESULTS

Overall data from 157 patients (78 females) were analyzed. Median serum gastrin levels were higher in females than males (92 vs. 60 pg/mL; P=0.001). Simple linear regression showed a correlation between serum gastrin levels and gender (P=0.0008) as well as PPI exposure in mg/kg (P=0.0001) and mg/m (P=0.0001). Multiple linear regression analysis showed that PPI exposure, both in mg/kg (β=0.95 [CI=0.4-1.5]; P=0.001) and mg/m (β=0.02 [CI=0.0-0.0]; P=0.0015) along with female gender (β=0.2 [CI=0.0-0.4]; P=0.02) predicted higher gastrin values.

CONCLUSIONS

Dosage and female gender seem to play an important role in the development of gastrin elevation on PPI therapy. A significant correlation was found between fasting serum gastrin and dosage of PPIs over weight and body surface area.

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.

Study of Gender Differences in Proton Pump Inhibitor Dose Requirements for GERD: A Double-Blind Randomized Trial

GOALS

To determine the proportion of patients with gastroesophageal reflux disease who are on proton pump inhibitors (PPIs) who could reduce their prior dosage by half, and identify predictors of successful step-down.

BACKGROUND

Appropriate hypergastrinemia results from gastric acid inhibition. A gender difference in fasting gastrin with higher levels among women than among men on long-term PPI therapy has been demonstrated.

STUDY

Patients with endoscopically verified erosive esophagitis on long-term PPI therapy were randomized double blindly to step down their dose by half or continue with the same dose for 8 weeks. Fasting gastrin levels were measured before and after treatment. The primary endpoint was successful step-down throughout the study period.

RESULTS

Overall, 100 patients were randomized, 49 (24 females) to continue with the same dose as before and 51 (25 females) to step down. Female patients had higher gastrin levels compared with male patients: 78 pg/mL (IQR, 50 to 99) versus 50 pg/mL (IQR, 36 to 74) (P=0.007). Among those randomized to the step-down intervention only 3/25 (12%) women failed to complete the 2 months of lower-dose therapy versus 9/25 (36%) men (P=0.09). Female gender (P=0.048) was the strongest predictor for successful step-down (odds ratio=1.27; 95% CI, 1.01-1.60). The chance of failing to maintain symptom control was twice as high in the reduction group (24%) as compared with the control group (13%) (P=0.2).

CONCLUSIONS

Female patients on long-term PPI therapy were 3 times more likely to tolerate half of their prior dose. Female gender had higher probability for successful step-down. These results indicate that women with gastroesophageal reflux disease might manage with lower doses of PPIs as compared with men.European Clinical Trial Database (https://eudract.ema.europa.eu/), number 2013-002067-26.

A Rapid and Accurate Method to Evaluate Helicobacter pylori Infection, Clarithromycin Resistance, and CYP2C19 Genotypes Simultaneously From Gastric Juice

Because Helicobacter pylori (H pylori) would cause carcinogenesis of the stomach, we need sufficient information for deciding on an appropriate strategy of eradication. Many factors affect the efficacy of eradication including antimicrobial resistance (especially clarithromycin resistance) and CYP2C19 polymorphism. This study was to survey the efficiency of gastric juice for detecting H pylori infection, clarithromycin resistance, and CYP2C19 polymorphism.The specimens of gastric juice were collected from all patients while receiving gastroscopy. DNA was extracted from gastric juice and then urease A and cag A were amplified by polymerase chain reaction (PCR) for detecting the existence of H pylori. By PCR-restriction fragment length polymorphism (PCR-RFLP), the 23S rRNA of H pylori and CYP2C19 genotypes of host were examined respectively. During endoscopy examination, biopsy-based specimens were also collected for rapid urease test, culture, and histology. The blood samples were also collected for analysis of CYP2C19 genotypes. We compared the results of gastric juice tests with the results of traditional clinical tests.When compared with the results from traditional clinical tests, our results from gastric juice showed that the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and accuracy to detect H pylori infection were 92.1% (105/114), 92.9% (143/154), 90.5% (105/116), 94.1% (143/152), and 92.5% (248/268), respectively. The SEN, SPE, PPV, and NPV to detect clarithromycin resistance were 97.3% (36/37), 91.5% (43/47), 90.0% (36/40), and 97.7% (43/44), respectively. By using PCR-RFLP, the consistency of human CYP2C19 gene polymorphism from blood samples and gastric juice was as high as 94.9% (149/157).The manipulated gastric juice is actually an effective diagnostic sample for evaluation of H pylori existence, clarithromycin resistance, and host CYP2C19 polymorphism.

Diagnosis of Helicobacter pylori: What should be the gold standard?

Since the discovery of Helicobacter pylori (H. pylori) in 1983, numerous detection methods for the presence of the bacterium have been developed. Each one of them has been associated with advantages and disadvantages. Noninvasive tests such as serology, ¹³C urea breath test (UBT) and stool antigen tests are usually preferred by the clinicians. Serology has its own limitation especially in endemic areas while ¹³C UBT is technically very demanding. The stool antigen detection method, although specific, is usually associated with poor sensitivity. The ¹³C UBT is believed to be specific, but with present revelation of the fact that stomach is colonized by many other urease producing bacteria makes it questionable. Histology, culture, rapid urease test and polymerase chain reaction (PCR) are the tests which are carried out on antral biopsies collected by invasive means. Histology has been proposed to be very sensitive and specific but the question is how by simply looking the morphology of the bacteria in the microscope, one can claim that the curved bacterium is exclusively H. pylori. Rapid urease test (RUT), the doctor’s test, is also challenged because the presence of other urease producing bacteria in the stomach cannot be denied. Moreover, RUT has been reported with poor sensitivity specially, when density of the bacterium is low. Isolation of H. pylori is essential to investigate its growth requirements, antibiotic susceptibility testing, studying virulence factor to develop vaccine and many more explorations. It has also got several disadvantages i.e., special condition for transporting, media, incubation and few days waiting for the colonies to appear, apart from the speed essentially needed to process the specimens. Till date, majority of the microbiological laboratories in the world are not equipped and trained to isolate such fastidious bacterium. The option left is PCR methods to detect H. pylori’s DNA in gastric mucosa, gastric juice, saliva, dental plaques and environmental specimens. There are speculations for false positivity due to detection of non-pylori Helicobacters due to genetic sharing; and false negativity due to low bacterial counts and presence of PCR inhibitors. However, specimen collection, transportation and processing do not require speed and special conditions. PCR based diagnosis may be considered as gold standard by designing primers extremely specific to H. pylori and targeting at least more than one conserved genes. Similarly specificity of PCR may be improved by use of internal Primers. Further, nested PCR will take care of false negatives by countering the effect of PCR inhibitors and low bacterial counts. Therefore, nested PCR based methods if performed properly, may be proposed as gold standard test.

The effects of long-term therapy with proton pump inhibitors on meal stimulated gastrin

BACKGROUND

Dyspepsia develops in healthy volunteers after withdrawal of proton-pump inhibitors. This phenomenon, attributed to rebound acid hypersecretion, is thought to be mediated by reflex hypergastrinemia.

AIMS

To measure fasting and postprandial gastrin in patients on long-term proton-pump inhibitor treatment and correlate gastrin levels with the duration of treatment and other potential predictors.

METHODS

In this cross sectional study patients, with erosive esophagitis, on long-term proton-pump inhibitor treatment and healthy controls underwent gastrin measurements at baseline and four times following a meal and Helicobacter pylori status was determined.

RESULTS

A total of 100 patients and 50 controls were studied. Pre- and postprandial gastrin levels were higher in patients (p<0.001). No significant correlation was found between the area under the gastrin-curve and the treatment duration. Female patients had significantly higher gastrin levels than males pre- and postprandial, whereas such differences was not found in the control group. Female gender was the only independent predictor of s-gastrin levels (OR 2.50 compared to males, 95% CI: 1.08-5.76, p=0.032) in the patient group.

CONCLUSION

Gastrin values were higher in patients compared to controls. There was no correlation between gastrin levels and treatment duration. Female patients had significantly higher gastrin values than males.

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.

Clinical usefulness of culturing H. pylori from gastric juice in patients with severe neurological impairment

OBJECTIVES

To clarify the diagnostic usefulness of culturing Helicobacter pylori from gastric juice for the diagnosis of H. pylori infection in patients with neurologic impairment.

METHODS

Seventy-five patients (44 males, 31 females) with severe neurologic impairment admitted to Tokyo Children's Rehabilitation Hospital were included in this study. Samples of gastric juice obtained from these patients were put into Helicoporter, a transport medium for H. pylori. Samples were then centrifuged and sediment was inoculated onto a culture medium. Polymerase chain reaction assays were performed on 41 gastric juice samples for comparison with results of culture. Tests for occult blood in gastric juice and serum anti-H. pylori immunoglobulin G were tested for all patients.

RESULTS

H. pylori was isolated from 33 of 75 gastric juice samples by culture (positive rate, 44%). There was agreement between results of culture and polymerase chain reaction assays in 38 samples (93%). Twenty-two samples were positive and 16 were negative by both methods. In H. pylori immunoglobulin G-positive patients, occult blood was more frequently found in the culture-positive group (92%) than in the culture-negative group (59%) (P <0.025). The rate of detection of occult blood in immunoglobulin G-negative patients was similar in the culture-positive group (44%) and culture-negative group (50%).

CONCLUSIONS

The combination of a culture method using gastric juice and a serum H. pylori immunoglobulin G assay was not invasive and clinically useful for evaluating H. pylori infections among handicapped patients.

Diagnostic value of culture, histology and PCR for Helicobacter pylori in the remnant stomach after surgery

BACKGROUND

Diagnosis of Helicobacter pylori infection in the remnant stomach has not been established.

AIMS

To investigate the diagnostic value of culture, histology, PCR and serum IgG against H. pylori (ELISA) with and without eradication therapy in the remnant stomach, compared with the unoperated stomach.

METHODS

Biopsy samples for bacterial culture and histological diagnosis of H. pylori were taken from the stoma and upper corpus of the remnant stomach and gastric juice was used for PCR assay.

RESULTS

Bacterial culture-based diagnosis in the remnant stomach, sensitivity and specificity of culture were 95.1%, 100%; histology 89%, 92.3%; PCR 66%, 89.7%; and ELISA 100%, 50%, respectively, in cases without H. pylori eradication therapy. In assessment of the results of therapy for the remnant stomach, sensitivity and specificity of culture were 100%, 100%; histology 80%, 96.8%; PCR 80%, 91.7%; and ELISA 100%, 0%, respectively.

CONCLUSION

Bacterial culture had the highest diagnostic value in the remnant stomach as well as unoperated stomach. Sensitivity by histology and PCR was lower in the remnant stomach than the unoperated stomach, but specificity values were equal. Serum ELISA assay was not suitable for the remnant stomach.

Association between Helicobacter bilis in bile and biliary tract malignancies: H. bilis in bile from Japanese and Thai patients with benign and malignant diseases in the biliary tract

Japan and Thailand have high incidences of bile duct carcinoma and gallstones. The presence of Helicobacter bilis (H. bilis) detected by polymerase chain reaction (PCR) and 16S rRNA analysis in bile samples from Chileans with chronic cholecystitis was reported. The association between H. bilis in bile and biliary tract malignancies has not been investigated, and therefore the aim of this study is to determine whether malignant diseases of the biliary tract are associated with the presence of H. bilis in bile samples obtained from two high-risk populations. Bile samples from 45 Japanese and 40 Thai patients were subjected to PCR analysis using H. bilis-specific primers, and six of the H. bilis amplicons were sequenced. Thirteen out of 15 (87%) Japanese and 11 out of 14 (79%) Thai patients with bile duct or gallbladder cancer tested positive for the presence of H. bilis in their bile. Eight out of 16 (50%) Japanese and 10 out of 26 (38%) Thai patients with gallstone and / or cholecystitis tested positive for H. bilis. Only 4 out of 14 (29%) subjects without biliary disease tested positive for H. bilis among the Japanese. Bile duct and gallbladder cancer showed significantly higher positive rates for H. bilis than did the non-biliary diseases among the Japanese (P < 0.01) and the odds ratios for bile duct or gallbladder cancer with H. bilis in comparison with gallstone and / or cholecystitis were 6.50 (95%CI 1.09 - 38.63) in the Japanese and 5.86 (1.31 - 26.33) in the Thai patients. In conclusion, H. bilis infection in bile was associated with biliary tract and gallbladder cancers in two high risk populations, Japanese and Thai.

PCR detection of Helicobacter pylori in string-absorbed gastric juice

Molecular methods for detection of Helicobacter pylori infection have been shown to be highly sensitive in gastric biopsies and cultures. The objective of this work was to compare PCR detection of H. pylori DNA in string-absorbed gastric juice and in gastric biopsies. The study was performed in 47 dyspeptic adult patients undergoing endoscopy, and infection was detected by amplification of a segment of H. pylori ureA gene. Of the 29 patients positive in biopsy analysis, 23 (79%) were also positive in the gastric string. PCR analysis of gastric strings is a sensitive and safe procedure to detect H. pylori when endoscopy is not indicated, and may be of great clinical and epidemiological usefulness in determining effectiveness of eradication therapies, typing virulence genes and detecting antibiotic resistance mutations.

Comparison of PCR and common clinical tests for the diagnosis of H. pylori in dyspeptic patients

Helicobacter pylori has been recognized as a major gastric pathogen. The objective of this study was to assess the diagnostic value of common clinical tests to detect H. pylori infection, by comparison with PCR. Serum and gastric biopsy specimens from 106 dyspeptic patients were examined. Serology was performed with Pyloriset Dry test, and biopsies were examined histologically, for rapid urease activity and PCR amplification of an ureA gene segment of H. pylori. PCR primers were specific for H. pylori and required at least 1.47 pg of H. pylori DNA, corresponding to about 800 bacterial cells. According to serology, histology, rapid urease, and PCR, positive results were respectively found in 56%, 86%, 64%, and 85% of dyspeptic patients, primarily with gastritis. Relative to PCR, the sensitivity (and specificity) was 55% (38%) for serology, 86% (13%) for histology, 70% (69%) for urease. When combining histology and urease, Bayesian analysis of data indicated no advantage of using combined methods over rapid urease test alone. Histology should not any longer be considered a gold standard test for Helicobacter pylori. Urea breath test still seems the first option for non invasive diagnostic. If an invasive diagnostic is justified, highly specific and sensitive molecular methods should be used to examine specimens.

Aging increases, and duodenal ulcer reduces the risk for intestinal metaplasia of the gastric corpus in Japanese patients with dyspepsia

BACKGROUND AND AIMS

The classification of gastritis by using the revised Sydney system suggests that there are two types of Helicobacter pylori-related gastritis. The aim of the present study was to examine the risk factors that might be involved in the presence of either atrophic gastritis or intestinal metaplasia of the gastric corpus of Japanese patients.

METHODS

Biopsy samples were obtained from the gastric corpus in 154 patients with dyspepsia, and the degree of atrophy or intestinal metaplasia was determined histologically. The correlation between several variables and presence of atrophy or intestinal metaplasia was evaluated by using multivariate analysis.

RESULTS

Among the 11 variables, which included age, peptic ulcer diseases and H. pylori infection, H. pylori infection was the major risk factor associated with the presence of atrophic gastritis or intestinal metaplasia of the gastric corpus. In contrast, duodenal ulcer (DU) disease reduced the risk of contracting both conditions. Age was an independent risk factor only for intestinal metaplasia of the gastric corpus. When 128 H. pylori-positive subjects were analyzed, DU and age were similarly associated with the presence of both conditions.

CONCLUSIONS

These results suggest that DU reduces the risk for contracting atrophic gastritis and intestinal metaplasia, and age is an independent risk factor for intestinal metaplasia of the gastric corpus in dyspeptic Japanese patients.

Helicobacter pylori infection in the remnant stomach after gastrectomy: with special reference to the difference between Billroth I and II anastomoses

Helicobacter pylori infection is associated with many gastric diseases, such as peptic ulcer and gastric cancer. We examined the remnant stomach for H. pylori infection after gastrectomy for gastric cancer or peptic ulcer between October 1992 and July 1997. H. pylori DNA in the gastric juice of 109 patients [mean age 62.4 years, male/female 78/31, gastrectomy for gastric cancer 83/peptic ulcer 26, Billroth I (BI) anastomosis 72/Billroth II (BII) 37, mean postoperative interval 6.0 years] was amplified by PCR and detected by Southern blot hybridization. The serum of 135 patients was assayed by ELISA for IgG antibody against H. pylori (mean age 61.8 years, male/female 99/36, gastrectomy for gastric cancer 111/peptic ulcer 24, BI anastomosis 93/BII 42, mean postoperative interval 5.4 years). H. pylori was positive in 68/109 (62.4%) by PCR and 113/ 135 (83.7%) by ELISA. H. pylori cytotoxin gene cagA, a H. pylori virulence factor gene, was found in 15/16 (93.8%) cases by PCR. A significant difference in H. pylori positivity by PCR was found according to the type of anastomosis (BI vs. BII) but not according to age group, sex, disease (cancer or ulcer), or postoperative interval by PCR and ELISA. BII anastomosis was followed by a significantly lower rate of H. pylori infection (17/37; 45.9%) than BI anastomosis (51/72; 70.8%; p=0.01) according to the results of PCR. Moreover, some patients with BII anastomosis (3/8; 37.5%) showed positive to negative seroconversion for H. pylori infection after the operation (mean 2.47 years) according to the results of ELISA, but this phenomenon was not observed in patients with BI (0/12) anastomosis. This may reflect the role of bile reflux, which is more common in BII than BI, because bile reflux interferes with colonization by H. pylori.

Role of Helicobacter pylori infection in perforation of peptic ulcer: an age- and gender-matched case-control study

Evidence showed a marked decrease in recurrence rate of peptic ulcer after eradication of Helicobacter pylori infection. However, whether H. pylori infection is etiologically related to perforation of peptic ulcer remains to be clarified. We therefore conducted an age- and gender-matched case-control study between perforated and nonsurgical peptic ulcers in H. pylori infection and examined differences in the cytotoxin genes cagA and vacA. Serum H. pylori IgG antibody (ELISA) was positive in 20/21 (95%) of perforated vs. 37/40 (93%) of nonsurgical duodenal ulcers and in 5/5 (100%) of perforated vs. 24/28 (86%) of nonsurgical gastric ulcer patients. Positivity of H. pylori DNA in gastric juice, which was amplified by PCR and identified by Southern blot hybridization, was 17/23 (74%) of perforated vs. 32/45 (71%) in the nonsurgical duodenal ulcer group. Positivity of the cytotoxin genes cagA and vacA in H. pylori DNA-positive gastric juice was as follows: perforated vs. nonsurgical duodenal ulcer, cagA 11/ 13 (85%) vs. 24/27 (89%); vacA1: 9/13 (69%) vs. 22/27 (82%); vacA2 8/13 (62%) vs. 21/27 (78%). There were no significant differences between the perforated and nonsurgical peptic ulcer groups for these H. pylori serum and gene markers. It is assumed that H. pylori infection is not etiologically related to perforation of peptic ulcer.

Cytotoxin genes of Helicobacter pylori in chronic gastritis, gastroduodenal ulcer and gastric cancer: an age and gender matched case-control study

Helicobacter pylori (H. pylori) infection is involved in many gastrointestinal diseases, such as chronic gastritis (CAG), peptic ulcer and gastric cancer (GCA). Both host factors and H. pylori strain differences may contribute to differences in the diseases. Thus, we conducted an age and gender matched case-control study of 35 patients each with CAG, gastric ulcer (GUL), duodenal ulcer (DUL) and gastric cancer (GCA) to examine the role of strain differences of the H. pylori cytotoxin genes cagA and vacA in these diseases. We employed polymerase chain reaction to examine the gastric juice for H. pylori DNA. The test was positive for 26 (74.3%) CAG, 29 (82.9%) GUL, 28 (80.0%) DUL and 27 (77.1%) GCA patients, showing no statistically significant difference among the diseases (P = 0.84). cagA and vacA genes (picked up by using a vacA1 + vacA2 primer pair which detected non-variable regions of the vacA gene) were detected by PCR in the H. pylori DNA-positive cases as follows: CAG, 92.3% and 76.9%; GUL, 100% and 86.2%; DUL, 89.3% and 89.3%; GCA, 92.6% and 85.2%, respectively. No statistically significant differences were found in the frequencies of these cytotoxin genes in H. pylori-positive cases among the various gastric diseases (P = 0.39 for cagA and P = 0.64 for vacA).