High sensitivity and specificity of a laboratory-based serological test, pylori DTect ELISA, for detection of Helicobacter pylori infection

Epidemiology of Helicobacter pylori in Australia: a scoping review

Background

Helicobacter pylori (H. pylori), a bacterium implicated in the development of peptic ulcer and gastric cancer, is estimated to infect around half the world's population. Its prevalence in Australia is unclear. This scoping review aimed to evaluate all Australian literature providing estimates of the prevalence of H. pylori.

Methods

Australian studies examining H. pylori prevalence from 1982 onwards were eligible for inclusion. Medline, Embase and Scopus databases, and grey literature sources, were searched. Two independent reviewers undertook a two-stage screening process. Data were extracted by two independent reviewers using a pre-specified template.

Results

Of 444 identified studies, 75 were included in the review. H. pylori prevalence in Australian population-based studies (n = 8) ranged from 38.0% in 1991 to 15.1% in 2002; however, estimated prevalence across all non-clinical population studies in diverse sub-groups (n = 29) has varied dramatically. Decreased prevalence has been more marked in populations with gastrointestinal symptoms and conditions compared to non-clinical populations. Data on H. pyloriprevalence in vulnerable populations are lacking.

Conclusions

This is the first scoping review of Australian studies reporting H. pylori prevalence. A wide range of study designs, population groups, geographic regions, and diagnostic methods was included, involving data collected over a 50-year period (1969 to 2018). The summary of H. pylori prevalence estimates over time in this review points to a decrease in prevalence in Australia, particularly among populations with gastrointestinal symptoms and illnesses; however, it is unknown whether there is inequity in prevalence trends across vulnerable sub-groups of the Australian population. Future research and interventions supporting the health and wellbeing of vulnerable populations is required to ensure equitable health gains are made for all.

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.

Development of an in-house enzyme-linked immunosorbent assay based on surface whole cell antigen for diagnosis of Helicobacter pylori infection in patients with gastroduodenal ulcer disease

Helicobacter pylori (H. pylori) is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. More than 50% world population is colonized by H. pylori, which is closely related to the chronic gastritis and gastric ulcer infection. In this study, a total of 214 gastritis patient's serum samples were screened for anti-H. pylori IgG antibody. A 96-well plate coated with 20 μg/ml antigen and hundred-fold diluted patient's serum was allowed to react. After extensive washing with buffer, 1:2,500 diluted conjugated secondary antibody was added. Later substrate was added to observe positivity by measuring the intensity of color. Statistical analyses were performed, and p value of <0.01 was taken as significant; 84% male patients and 89% female patients, respectively, tested positive for H. pylori, while agewise distribution was 35-45 years males (40%) and 35-55 years females (52%) were found highest number of H. pylori infected patients. In-house ELISA based on surface whole cell antigen (wELISA) showed a sensitivity of 93%, specificity of 100%, accuracy 94% and κ value 0.86 with significant correlation R-0.77020; p < 0.0001. We conclude that H. pylori local isolates surface antigen was satisfactory for diagnosis as different parameters were adjusted according to the local H. pylori isolates. Fluctuations in serum antibody titer predict the variation in an individual's response of the host against H. pylori. In-house wELISA could provide a reliable and a clinically useful method for the diagnosis of H. pylori infection in patients of Karachi, Pakistan.

Immunoblotting using multiple antigens is essential to demonstrate the true risk of Helicobacter pylori infection for gastric cancer

BACKGROUND

Enzyme-linked immunosorbent assays (ELISAs) for detection of Helicobacter pylori infection, using IgG antibodies, may significantly underestimate the association with gastric cancer.

AIM

To compare associations between H. pylori and cardia (CGC) and noncardia gastric cancer (NCGC) using ELISA and immunoblotting and determine the effect of atrophic gastritis on detection.

METHODS

Nested case-control study within the Melbourne Collaborative Cohort Study. Helicobacter pylori antibodies were detected in subjects with CGC (n = 18), NCGC (n = 34) and controls (n = 69 and 134 respectively) using ELISA (pylori DTect) and immunoblot (Helicoblot 2.1). Pepsinogen I levels were measured using ELISA.

RESULTS

Using ELISA, H. pylori-positivity in the CGC group was 33% vs. 35% in controls [odds ratio (OR = 0.9, 95% CI: 0.3-2.7)], while that in the NCGC group was 79% vs. 63% in controls [OR = 2.3 (95% CI: 0.9-5.8)]. Based on immunoblotting, H. pylori-positivity in the CGC group was 44% vs. 39% in their controls [OR = 1.2 (95% CI: 0.4-3.4)], while that in the NCGC group was 94% vs. 63% in controls [OR = 10.6 (95% CI: 2.4-47.4)]. Pepsinogen I levels in the NCGC cases and controls showed the lowest median level (4 ng/mL) to be in subjects negative by ELISA but positive by immunoblotting.

CONCLUSION

Immunoblotting improves the accuracy of H. pylori studies involving gastric cancer.

Helicobacter pylori: testing and treatment

Helicobacter pylori is an important pathogen worldwide. Accurate diagnosis and appropriate therapy is important in clinical practice. Invasive tests that accurately identify current infection include the biopsy urease test and histology. The best noninvasive tests for diagnosis include the urea breath test and stool antigen testing. Proton pump inhibitor therapy can lead to false-negative H. pylori test results, and treatment should be stopped for 1-2 weeks prior to testing if possible. In the setting of bleeding peptic ulcer disease, urea breath testing is recommended to rule out a false-negative biopsy test result if needed. The current recommendations for when to test for H. pylori vary around the world. Well-accepted indications include active and past ulcer disease, and gastric-mucosa associated lymphoid tissue lymphoma. There is no universal agreement regarding whether all patients with functional dyspepsia should be tested and treated, although this is an evidence-based recommendation. There is also evidence that H. pylori eradication prevents peptic ulcer disease in those starting NSAIDs long term. Primary treatment remains triple therapy with 10-14 days probably being superior to shorter courses of therapy. Quadruple therapy is recommended if standard triple therapy fails. Salvage therapies with levofloxacin, rifabutin or furazolidone have been identified. Novel approaches to treatment include sequential therapy and use of adjuvants.

Photocatalysis effect of nanometer TiO2 and TiO2-coated ceramic plate on Hepatitis B virus

The photocatalysis effect of nanometer TiO2 particles and TiO2-coated ceramic plate on Hepatitis B virus surface antigen (HBsAg) was investigated. The ELISA (enzyme-linked immunosorbent assay) standard method was used to assess the efficiency of TiO2 material to destroy the HBsAg. The research has shown that the suspension of TiO2 (0.5g/L) can destroy most of the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.6mW/cm(2) at 365nm wavelength, or under the sunlight irradiation for a few hours. TiO2-coated ceramic plates can also destroy the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.05mW/cm(2) at 365nm wavelength or under the room daylight for a few hours.

Seroprevalence of Helicobacter pylori in Chinese patients on continuous ambulatory peritoneal dialysis

BACKGROUNDS AND AIMS

There is relatively little data on the seroprevalence of Helicobacter pylori in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). This study aims at establishing the seroprevalence of and the factors associated with H. pylori infection in Chinese CAPD patients.

METHODS

All CAPD patients from a single dialysis centre were invited to participate in the study. Diagnosis of H. pylori infection was made serologically by the pylori DTect ELISA method. Dyspeptic symptoms were assessed by the Hong Kong Index of Dyspepsia (HKID) Questionnaire. Demographic, clinical and laboratory parameters were correlated with the H. pylori serology results.

RESULTS

One hundred and thirty-six Chinese CAPD patients were included in the study. The mean age of the patients was 61.8 +/- 12.5 years with a male to female ratio of 1:1.4. The mean duration of CAPD was 54 +/- 42 months. Thirty-five patients (26%) have positive serology against H. pylori. Nineteen patients had a HKID score of >16. There was no association between H. pylori seropositivity and dyspeptic symptoms (P = 0.62). Patients who were seropositive for H. pylori were significantly older (64.9 +/- 9.5 years vs 60.7 +/- 13.2 years, P < 0.05) and had lower KT/V-values than patients who were seronegative for H. pylori (1.88 +/- 0.3 vs 2.03 +/- 0.3, P < 0.05). Patients with positive or negative H. pylori serological status did not differ in terms of demographic parameters (e.g. sex, duration of CAPD), clinical factors (e.g. bodyweight, body mass index, hepatitis status, use of H(2) antagonists or proton pump inhibitors) and laboratory data (e.g. haemoglobin, serum urea, creatinine, albumin and parathyroid hormone levels).

CONCLUSIONS

The seroprevalence of H. pylori infection among Chinese CAPD patients is 26%. Helicobacter pylori seropositivity is not associated with dyspepsia. Older age and lower KT/V-values appear to be associated with the development of H. pylori seropositivity in our dialysis population.

Helicobacter pylori serology in a birth cohort of New Zealanders from age 11 to 26

AIM

To determine seroprevalence of Helicobacter pylori (H pylori) in the Dunedin Multidisciplinary Health and Development Study (DMHDS) at age 26 in order to investigate seroconversion and seroreversion from age 11 to 26 and the association of seropositivity with risk factors for H pylori infection.

METHODS

Participants in the DMHDS at age 26 and retrospectively at age 21 were tested for H pylori antibodies using two commercially available ELISA kits. Gender, socioeconomic status (SES), smoking, educational attainment and employment at age 26 were tested for association with H pylori seropositivity.

RESULTS

At ages 21 and 26, seroprevalence of H pylori using one or other kit was 4.2% (n = 795) and 6.3% (n = 871) respectively. Seroreversion rate was lower than seroconversion rate (0.11% vs 0.53% per person-year) in contrast to the period from age 11 to 21 when seroreversion rate exceeded seroconversion rate (0.35% vs 0.11% per person-year). Serology in those tested at ages 11, 21, and 26 remained unchanged in 93.6% of the sample. Seroprevalence at age 26 was lower among those with a secondary school qualification (P = 0.042) but was not associated with gender, SES, smoking or employment status.

CONCLUSION

H pylori seroprevalence in a New Zealand birth cohort remains low between ages 11 and 26. H pylori infection remains stable from childhood to adulthood although seroreversion seems to be more common in the adolescent years than in young adults.

Diagnosis of Helicobacter pylori infection and diseases associated with Helicobacter pylori by Helicobacter pylori outer membrane proteins

AIM: To examine the serological response of patients with upper gastrointestinal diseases and Helicobocter pylori (H pylori) infection to two H pylori outer membrane proteins (OMPs) (M_r18000 and M_r26000) acquired by gene recombinant technique, and to determine the diagnostic significance of serological tests derived from these OMPs.

METHODS: Recombinant vectors encoding the two H pylori OMPs were used to transform and express in BL21 (DE3) E.coli. After purification with Ni²⁺-NTA agarose resin, colloid gold kits were prepared with purified recombinant proteins to detect H pylori infection and H pylori-associated diseases by the immunity-marker technology. We selected 150 patients with H pylori infection and digestive symptoms without previous treatment, including chronic gastritis (n = 60), duodenal ulcer (n = 30), gastric ulcer (n = 30), and gastric cancer (n = 30). As controls, 33 H pylori-negative healthy volunteers were also recruited. Serum samples were collected from all subjects, and the antibodies to specific proteins of H pylori were tested with the colloid gold test kits. The sensitivity, specificity and accuracy of the colloid gold tests were evaluated, by using the combination of standard diagnostic methods (¹³C urea breath test and bacteria culture) and classic enzyme-linked immunosorbent assay (ELISA) as reference.

RESULTS: After purification with Ni²⁺-NTA agarose resin, the purity of recombinant fusion proteins was about 95%. The recombinant fusion proteins were recognized by the specific monoclonal antibodies against the two H pylori OMPs, as demonstrated by the ELISA. Of the 150 serum samples from patients infected with H pylori 141 (94.0%) responded positively to the recombinant protein with M_r26000, while the seropositive rates were 95.0%, 96.7%, 96.7% and 90.0% for patients with H pylori-associated chronic gastritis, duodenal ulcer, gastric ulcer, and gastric cancer respectively. The sensitivity, specificity, and accuracy of the colloid gold kit with M_r26000 protein were 94.0%, 97.0%, and 94.5%, respectively. Compared with the classic ELISA, bacteria culture and ¹³C urea breath test results in detecting H pylori-infection, there was no significant difference (P > 0.05). For the colloid gold kit with M_r18000, the seropositive rates were 52.0%, 40.0%, 40.0%, 53.3% and 86.7%, respectively, in H pylori-infected patients, and those with H pylori-associated chronic gastritis, duodenal ulcer, gastric ulcer, and gastric cancer. There was a significant difference (P < 0.05) in seropositivity between patient with gastric cancer (86.7%) and those with other diseases (43.3%).

CONCLUSION: The two colloid gold kits derived from the recombinant OMPs are useful tools either for detecting H pylori infection, or for, predicting H pylori-associated gastric malignancy.

Cost-benefit analysis of Helicobacter pylori screening

BACKGROUND

Helicobacter pylori screening may markedly reduce mortality and morbidity in the decades ahead.

AIMS

This study explores the costs and benefits of population-based H. pylori screening in terms of health care cost taking into account all relevant H. pylori-related diseases.

MATERIAL AND METHODS

The computer-based decision analysis compared two strategies: (1) screen for H. pylori and treat those individuals who test positive, and (2) do not screen for H. pylori, and test and treat H. pylori only if related clinical symptoms appear. The model estimated the discounted H. pylori-related accumulative health care costs from screening age to death in both strategies. The baseline case estimates cost-benefit for screenees aged 15-45 years. The main outcome measure is the incremental health care cost per case in the screening compared with the no-screening alternative. The probability estimates were obtained from the Finnish Vammala H. pylori screen and treat project, including 5288 subjects in the years 1996-1998, published studies, national statistics and hospitals' internal accounts.

RESULTS

The incremental cost per case was 26 US dollars in the screening compared with the no-screening alternative. It was lowest in the group aged 45 years, where H. pylori screening showed cost savings per case.

CONCLUSIONS

H. pylori screening is more favourable in the older age cohorts. The estimated cost per screenee can be considered to be very acceptable if the current pathophysiological evidence on the potential effects of H. pylori eradication are confirmed in the future. However, there is uncertainty about the possible negative effect of eradicating H. pylori infection on gastro-esophageal reflux disease and esophageal adenocarcinoma. This could change the balance of benefits against risks of eradicating H. pylori infection.

Antralization of gastric incisura is topographically associated with increased gastric epithelial apoptosis and proliferation, but not with CagA seropositivity

BACKGROUND AND AIMS

Helicobacter pylori infection is linked with increased antralization at the gastric incisura. The present study aimed to determine if antralization is associated with altered gastric epithelial apoptosis and proliferation and with seropositivity of the cytotoxin-associated gene product A (CagA) of H. pylori.

METHODS

Gastric biopsies taken from the antrum, incisura, body and fundus of 75 patients (34 male, 41 female; mean age 59.5 years) were used for diagnosis of H. pylori infection and assessments of histological changes. Apoptosis and Ki-67 expression in epithelial cells were determined for the antral, incisura and body biopsies by immunohistochemistry. Serum samples were tested by enzyme-linked immunosorbent assays for anti-H. pylori and anti-CagA IgG antibodies.

RESULTS

Apoptotic index (AI) and Ki-67 proliferation index (PI) were greater in the presence (vs absence) of H. pylori infection at the antrum, incisura and body (all P < 0.001), and topographically associated with chronic gastritis and gastric atrophy/intestinal metaplasia at the antrum and incisura (all P < 0.001). Moreover, AI and PI were greater in the presence (vs absence) of antralization at the incisura (20.2 +/- 0.9 vs 11.4 +/- 0.1.1 and 48.9 +/- 2.5 vs 29.9 +/- 2.5, both P < 0.001). CagA seroprevalence was 41% in the 39 infected patients. CagA seropositivity was associated with gastric atrophy/intestinal metaplasia at the antrum (chi(2) = 4.67, P = 0.03) and incisura (chi(2) = 4.88, P = 0.03), but not associated with gastric epithelial apoptosis and Ki-67 expression, nor with antralization at the incisura.

CONCLUSIONS

Antralization of gastric incisura is topographically associated with increased gastric epithelial apoptosis and proliferation, but not with CagA seropositivity.

Diagnosis of Helicobacter pylori infection in adults with intellectual disability

Helicobacter pylori infection is common among adults with intellectual disability. The acceptabilities and accuracies of different diagnostic tests in this population are unknown. We aimed to determine (i) patient acceptability and (ii) performance characteristics of serology, fecal-antigen, and urea breath tests among adults with intellectual disability. One hundred sixty-eight such adults underwent H. pylori testing with serology and fecal-antigen tests, and a portion underwent treatment. One year later, the participants were retested with fecal-antigen, serology, and urea breath tests. The numbers of specimens obtained and difficulties in collection reported by caregivers were noted. Test performance characteristics were assessed among participants and 65 of their caregivers, using serology as the reference. All participants provided at least one specimen, despite reported collection difficulties for 23% of fecal and 27% of blood specimens. Only 25% of the participants provided breath specimens; failure to perform this test was associated with lower intellectual ability and higher maladaptive behavior. The sensitivity, specificity, and positive and negative predictive values of the fecal test (baseline and 12 months versus caregivers) were 70 and 63 versus 81, 93 and 95 versus 98, 96 and 92 versus 93, and 53 and 74 versus 93%, respectively; those of the urea breath test (12 months versus caregivers) were 86 versus 100, 88 versus 95, 75 versus 89, and 94 versus 100%, respectively. With assistance, fecal or blood specimens for H. pylori assessment can be provided by most patients with intellectual disability regardless of their level of function or behavior. Only those with greater ability can perform the urea breath test. Using serology as the reference test, the limitations of performance characteristics of the fecal-antigen and urea breath tests are similar to those among a control group of caregivers.

Effect of Helicobacter pylori infection and low-dose aspirin use on iron stores in the elderly

BACKGROUND AND AIMS

Helicobacter pylori infection has been associated with lower ferritin levels in some adult populations, but subsets of potentially higher risk subjects, such as the elderly have not been examined. The aim of the present study was to determine the impact of H. pylori infection and low-dose aspirin use on iron stores in a well elderly population.

METHODS

Consecutive subjects aged 65 years or older attending day care facilities were studied. Each subject was assisted in completing a medical questionnaire. Serum ferritin, hemoglobin, mean corpuscular volumes (MCV) and IgG antibodies (ELISA) against H. pylori were measured.

RESULTS

In 220 subjects (age 75 +/- 8 years), 42% were H. pylori seropositive (male 41%, female 44%). The median (IQR) ferritin level (ug/L) was higher in men 149 (89-280) than women 94 (54-161), p < 0.002. The ferritin levels were not different in H. pylori positive males 151 (105-283) compared with H. pylori negative males 145 (72-249), or H. pylori positive females 93 (60-142) compared with H. pylori negative females 97 (45-149). This relationship was not altered when controlled for non-steroidal anti-inflammatory agents (NSAID) use (9% of subjects), alcohol or dietary iron intake. Low-dose aspirin use was common (28%), but did not have an independent impact on iron stores: male users 181 (95-248), non-users 145 (86-284); female users 92 (43-162), non-users 95 (62-163). However, in female aspirin users, H. pylori infection was associated with significantly lower ferritin levels: 65 (43-112) compared with uninfected subjects 103 (41-180), p < 0.04.

CONCLUSIONS

In this well elderly population, the combination of H. pylori infection and low-dose aspirin use was associated with significantly lower serum ferritin concentrations in females. This difference supports the observation that H. pylori, even in asymptomatic subjects, may be a stressor of iron stores.

Clinical and pathological implications of IgG antibody responses to Helicobacter pylori and its virulence factors in non-ulcer dyspepsia

AIM

To determine whether pre-treatment antibody response to Helicobacter pylori virulence factors predicts eradication success and symptom relief 12 months after triple therapy in non-ulcer dyspepsia.

METHODS

H. pylori-positive patients with non-ulcer dyspepsia received 1-week omeprazole-based triple therapy, or omeprazole plus placebos. Symptoms were assessed using a validated Likert scale. Gastric biopsies taken before and 12 months after treatment were used for histological examination. Pre-treatment blood samples were used for the detection of anti-H. pylori immunoglobulin G (IgG) antibodies, and specific IgG antibodies to 19.5-, 26.5-, 30-, 35-, 89- (VacA) and 116-kDa (CagA) antigens of H. pylori.

RESULTS

IgG antibodies to the six antigens were detected in 62%, 96%, 88%, 47%, 54% and 78% of patients, respectively. The presence of antibody to 19.5-, 26.5- or 30-kDa antigen was associated with an increased anti-H. pylori IgG absorbance index. IgG absorbance indices were greater in those with H. pylori eradication (vs. persistent infection). The prevalence of antibodies to the six antigens was not significantly different between those with symptom relief vs. those without. The 19.5-kDa antigen (P = 0.018) and VacA (P = 0.001) were independent risk factors for body gastritis.

CONCLUSIONS

An increased pre-treatment anti-H. pylori IgG absorbance index may be a useful predictor of the success of eradication therapy. Although the 19.5-kDa antigen and VacA were associated with body gastritis, none of the six antigens tested predicted symptom relief after triple therapy.

Evaluation of two stool antigen tests for the detection of Helicobacter pylori infection in the Chinese population

BACKGROUND AND AIM

The stool antigen test, the HpSA test, has been validated mainly in Western countries, but not properly in the Chinese population. Recently, another stool antigen test, the Apollo test, was developed, but its accuracy has rarely been validated. The aim of this study is to compare the accuracy of these two tests in the diagnosis of Helicobacter pylori infection in the Chinese population.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. During endoscopy, biopsies were taken for the rapid urease test and histological examination as the gold standard. Stool specimens were collected and used for the HpSA and Apollo tests.

RESULTS

Overall, 86 patients (39 males and 47 females, with a mean age of 55.8 years) were recruited. Helicobacter pylori infection was present in 44 (51%) patients as determined by the gold standard. The sensitivity, specificity and accuracy were 86.4, 100, and 93.0%, respectively, for the HpSA, and 90.9, 97.6, and 94.2%, respectively, for the Apollo test when cases with equivocal results were considered as positive. In addition, agreement was achieved in 81 (94.2%) cases between the two tests, with a Kappa value of 0.887.

CONCLUSION

Both the HpSA and Apollo tests achieve acceptable sensitivity and excellent specificity, with accuracies of over 90% for the detection of H. pylori infection in the Chinese population.

Topographic association of gastric epithelial expression of Ki-67, Bax, and Bcl-2 with antralization in the gastric incisura, body, and fundus

OBJECTIVES

Helicobacter pylori (H. pylon) infection seems to induce antralization (ie., gastric mucosal transformation from transitional or body type to antral type), which is strongly associated with gastric atrophy and intestinal metaplasia. The aim of this study was to determine the topographic associations of Ki-67 (a protein expressed in proliferative cells), Bax (a pro-apoptotic protein), and Bcl-2 (an antiapoptotic protein) expression with antralization.

METHODS

In each of 104 patients, eight biopsy specimens were taken from the gastric antrum, incisura, body, and fundus for the determination of H. pylori infection, histological changes, and epithelial expression of Ki-67, Bax, and Bcl-2. A labeling index (LI), i.e., the rate of positive cells over total cells counted, was used for Ki-67 and Bax expression. Bcl-2 overexpression was considered to be present if the rate of Bcl-2 positive cells over total cells counted was > or = 5%.

RESULTS

H. pylori infection was present at the gastric antrum, incisura, body, and fundus in 50, 48, 51, and 49 patients, respectively. Ki-67 LI was greater in the presence vs absence) of H. pylori infection at the antrum (51 vs 40), incisura (47 vs 36), body (43 vs 30), and fundus (41 vs 31) (all p < 0.001). At the incisura, Ki-67 LI was greater (47 vs 32, p < 0.001), Bax LI was lower (22 vs 30, p < 0.05), and prevalence of Bcl-2 overexpression was higher (44% vs 18%, p < 0.001) in the presence (vs absence) of antralization. Compared with normal mucosa, gastric atrophy/intestinal metaplasia were associated with an increased Ki-67 LI and decreased Bax LI at the antrum (49 vs 32 and 15 vs 23, respectively), incisura (47 vs 32 and 15 vs 26, respectively) (all p < 0.001). Bcl-2 overexpression was more frequent in gastric atrophy/intestinal metaplasia at the antrum (56% vs 11%, p < 0.001) and incisura (63% vs 19%, p < 0.001) compared with normal mucosa.

CONCLUSIONS

Antralization at the incisura is topographically associated with increased cell proliferation, reduced Bax expression, and Bcl-2 overexpression, which implies that antralization may be an important histological marker for future cancer risk.

Foetal intrauterine growth restrictions with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection has been associated with growth restriction in young children.

AIM

To determine whether there is an association between H. pylori infection and intrauterine growth restriction.

METHODS

Four hundred and forty-eight consecutive pregnant women (aged 15-44 years), attending for routine examinations in the third trimester, were enrolled. Clinical, demographic and previous obstetric data, as well as smoking history, were collected. At delivery, the weight, height, gender and status of the neonate were recorded; intrauterine growth restriction was defined if the birth weight was below the 10th percentile according to the gestational age for infants born in Australia.

RESULTS

Eighty-nine (20%) women were seropositive for H. pylori. The prevalence of H. pylori was significantly lower in Caucasians (17%) vs. non-Caucasians (42%, P < 0.0001). There were 34 (7.5%) cases of intrauterine growth restriction (7% Caucasians, 16% Asians, 12% Aborigines and 0% Pacific Islanders). Intrauterine growth restriction was more common in H. pylori-seropositive women than in H. pylori-seronegative women [13.5% vs. 6%; odds ratio (OR) = 2.41; 95% confidence interval (CI), 1.14-5.08; P = 0.018]. A multiple logistic regression model revealed that smoking (OR = 3.55; 95% CI, 1.62-7.79; P = 0.002), maternal height (OR = 0.48; 95% CI, 0.28-0.80; P = 0.005) and H. pylori seropositivity (OR = 2.59; 95% CI, 1.12-5.95; P = 0.025) were all independent risk factors for intrauterine growth restriction.

CONCLUSIONS

H. pylori infection in pregnant women may affect foetal intrauterine growth.

Optimal serological tests for the detection of Helicobacter pylori infection in the Chinese population

BACKGROUND

Numerous serological tests for the detection of Helicobacter pylori infection have been developed. However, many perform poorly when evaluated in the Chinese population.

AIM

To search for optimal serological tests for the detection of H. pylori infection in Chinese patients.

METHODS

Consecutive dyspeptic patients referred for upper endoscopy were recruited. During endoscopy, gastric biopsies were taken for the CLOtest and histological examination. Patients were then given a 13C-urea breath test. Sera were used to test for H. pylori infection, employing three commercial enzyme-linked immunosorbent assay kits (pylori DTect, HP IgG and GAP IgG). Results were compared with the gold standard defined by the CLOtest, histology and 13C-urea breath test.

RESULTS

Among the 142 patients (47 male, 95 female; mean age, 49 years) recruited, 81 (57%) were H. pylori-positive, 57 (40%) were H. pylori-negative and four (3%) were defined to be indeterminate. Using a self-defined cut-off value after calculation, the best accuracies for the pylori DTect, HP IgG and GAP IgG tests were 97%, 91% and 80%, respectively.

CONCLUSIONS

The pylori DTect test is an optimal serological test for the detection of H. pylori infection in Hong Kong Chinese patients. The HP IgG test may be used as an alternative.

Helicobacter pylori infection is not associated with diabetes mellitus, nor with upper gastrointestinal symptoms in diabetes mellitus

OBJECTIVE

The association between Helicobacter pylori (H. pylori) infection and diabetes mellitus is controversial. We aimed to determine the prevalence of H. pylori infection in patients with diabetes and nondiabetic controls, and assess whether H. pylori infection was associated with upper gastrointestinal (GI) symptoms in diabetes mellitus.

METHODS

A total of 429 patients with type 1 (n = 49) or type 2 (n = 380) diabetes mellitus (48.6% women, mean age 60.7 yr) and 170 nondiabetic controls (34.7% women, mean age 60.4 yr) were evaluated. All subjects completed a validated questionnaire (the Diabetes Bowel Symptom Questionnaire) to determine upper GI symptoms, and a blood sample was tested for H. pylori infection using a validated ELISA kit (sensitivity 96%, specificity 94%).

RESULTS

Seroprevalence of H. pylori was 33% and 32%, respectively, in patients with diabetes and controls (NS). In both groups, the seroprevalence was significantly higher in men than in women; 39% vs 25% (p = 0.002) in diabetic patients, and 40% vs 20% (p = 0.01) in controls. Patients with diabetes had a significantly higher prevalence of early satiety (OR = 2.30), fullness (OR = 3.15), and bloating (OR = 1.50) compared with controls. Upper GI symptoms were present in 49% of H. pylori-positive and 53% of H. pylori-negative patients with diabetes (OR = 0.87, 95% CI 0.58-1.31, p = 0.56). H. pylori infection was also not associated with any of the individual upper GI symptoms before or after adjustment for potential confounding factors. However, patient age and female gender were identified as independent risk factors for upper GI symptoms. Smoking was a risk factor for bloating and early satiety.

CONCLUSIONS

H. pylori infection appears not to be associated with diabetes mellitus or upper GI symptoms in diabetes mellitus.

Demographic and endoscopic characteristics of patients with Helicobacter pylori positive and negative peptic ulcer disease

OBJECTIVE

To identify demographic and endoscopic characteristics of patients with Helicobacter pylori positive and negative chronic peptic ulcer disease.

DESIGN

Cross-sectional study of peptic ulcer disease in prospectively recruited PATIENTS undergoing gastroscopy.

PATIENTS

277 consecutive patients referred for gastroscopy in 1996-1998.

MAIN OUTCOME MEASURES

Rapid urease test, culture and histological examination for H. pylori infection; anti-H. pylori IgG antibodies in serum; demographic data, intake of non-steroidal anti-inflammatory drugs (NSAIDs) in the preceding 3 months, and size, number and location of ulcers.

RESULTS

54 patients (19%) had evidence of peptic ulcer disease (34 gastric ulcer, 14 duodenal ulcer and 6 both gastric and duodenal ulcer); 45 had active chronic peptic ulcer disease and were analysed in detail. H. pylori was present in 25 (56%) of these patients; 10 (22%) had used NSAIDs and 7 of the NSAID group also had H. pylori infection. Of the patients with gastric ulcers, those with non-H. pylori, non-NSAID ulcers were significantly younger than both those with H. pylori-associated ulcers (mean age, 48 v. 65 years, P = 0.02) and those with NSAID-associated ulcers (mean age, 48 v 68 years, P = 0.02). The average size and number of gastric ulcers did not differ between patients with and without H. pylori infection. Of patients with duodenal ulcers, those with H. pylori infection had significantly fewer ulcers (1.1 v. 1.8, P = 0.04), although ulcer size was similar in the infected and uninfected groups.

CONCLUSIONS

Gastric ulcers may now be more common than duodenal ulcers. Gastric ulcers associated with H. pylori infection and/or NSAID use occurred mostly in older people, while non-H. pylori, non-NSAID gastric ulcers were more common in younger patients. In the duodenum, single ulcers were associated with H. pylori infection, and multiple ulcers were more frequent in the non-H. pylori, non-NSAID group.

Can helicobacter pylori serology still be applied as a surrogate marker to identify peptic ulcer disease in dyspepsia?

BACKGROUND

Helicobacter pylori infection and associated peptic ulcer disease (PUD) has become less common in some countries.

AIM

To determine if H. pylori serology alone or combined with a history of ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) and an age threshold can be used as an indirect ulcer test.

METHODS

Two hundred and fifty-two consecutive Australian patients (121 males, mean age 52 years) referred for endoscopy were enrolled. Blood was tested by a validated ELISA. At endoscopy, eight biopsies were taken for CLO-testing, culture and histology. NSAID use over the prior 3 months was recorded.

RESULTS

One hundred and six (42%) patients were seropositive for H. pylori, 48 (19%) patients had PUD and 30 (12%) used NSAIDs. Serology alone had a sensitivity of 52% and a specificity of 60% for identifying PUD; the sensitivity and specificity were 60% and 55%, respectively, when combined with a history of NSAID use. Serology, regardless of NSAID use, would have saved 23% in endoscopy workload but would have missed 17% of PUD cases if an age threshold of < 45 years was chosen for omitting endoscopy.

CONCLUSIONS

Serology was a poor ulcer test despite an excellent performance for detecting H. pylori. A strategy combining serology and an age threshold with a history of NSAID use to reduce endoscopy workloads may not always be appropriate.