Fabiana Landi

Helicobacter pylori and type 1 diabetes mellitus in children.

BACKGROUND Helicobacter pylori is a recognized gastroduodenal pathogen and H. pylori infection is one of the most common bacterial infections, usually acquired during childhood. However, diabetes mellitus is characterized by an increased susceptibility to infections. METHODS We compared the prevalence of H. pylori infection as well as cytotoxin-associated gene A-CagA-and vacuolating cytotoxin gene A-VacA-positivity in 103 children and adolescents with type 1 diabetes mellitus and in 236 nondiabetic children. We used a novel Recombinant ImmunoBlot Assay-Strip (RIBA SIA) with individual band for whole H. pylori lysate and recombinant CagA and VacA. RESULTS H. pylori-positive subjects, both diabetics and controls, were significantly older than negative subjects. In the whole group of diabetic patients the prevalence of each of the three reactivities was higher than in control subjects, reaching significance only for lysate. Only diabetic patients over 12 years of age, with a longer disease duration, had a higher prevalence of positive cases, although not significantly so. CONCLUSIONS In the first few years of disease, diabetic children do not differ from the nondiabetic population. Subsequently they show an H. pylori seroprevalence tendentially higher than that of controls of the same age. Therefore, H. pylori infection acquired in childhood and lasting several years, could be one of the causes of chronic atrophic gastritis, which is more frequent in longstanding diabetes mellitus.

Isotope ratio mass spectrometry (IRMS) versus laser-assisted ratio analyzer (LARA): a comparative study using two doses of.

This study was carried out to compare the measurements and the diagnostic accuracy of the traditional expensive IRMS and the new economical LARA system using two doses of [13C]urea + two different test meals in patients undergoing upper gastrointestinal endoscopy, both before and after anti-Helicobacter treatment. A total of 354 dyspeptic patients underwent endoscopy with gastric biopsies to diagnose H. pylori infection by CLO-test and histology. No patients had taken antibiotics, bismuth, or antisecretory drugs in the 4 weeks before testing. After overnight fasting, breath samples were collected simultaneously in both plastic and glass tubes at baseline and at 30 and 60 min after urea ingestion. In 237 patients 100 mg [13C]urea + Ensure and in 117 patients 75 mg [13C]urea + citric acid were given. The test was also performed with the two urea dosages and meals in 67 and 64 infected patients, respectively, four weeks after anti-Helicobacter therapy. H. pylori was considered eradicated when both biopsy-based tests were negative. A δ value >5‰ was considered positive. Breath samples with insufficient CO2 levels at both 30 and 60 min were excluded from final analysis (N = 37 in pre- and N = 8 in posttreatment). There was excellent agreement between overall δ values of the two machines with both [13C]urea 100 mg + Ensure and [13C]urea 75 mg + citric acid. The 95% CI of the difference against the mean was wider with the former (mean −1.3, +6.3, and −9.4) than with the latter urea dosage and test meal (mean −1.2, +5.2 and −8.1). LARA and IRMS were equally effective (P = NS) in distinguishing infected from uninfected patients before therapy using both doses of [13C]urea and test meals (sensitivity ranged from 95% to 99% and specificity from 95% to 97%). This good performance was maintained in the posttreatment phase (sensitivity ranged from 90% to 100% and specificity from 90% to 97%), without any statistical difference among the various combinations (P = NS). The LARA system is a valid alternative to IRMS in the diagnosis of H. pylori infection. Both machines provide highly reliable results after 30 min, so that the 60 min sample can be avoided. The dose of 75 mg + citric acid suffices to ensure an accurate UBT. The test performed with both devices and [13C]urea dosages is very effective also for posttherapy evaluation of H. pylori status.

Helicobacter pylori Seroconversion in Asymptomatic Blood Donors A Five-Year Follow-up

Several techniques have been developed to diagnose Helicobacter pylori infection and two noninvasive methods are available: carbon 13-urea breath test (UBT) and serology. Measurement of IgG serum antibodies by enzyme-linked immunosorbent assay (ELISA) is a reliable and inexpensive method for detection of infection. The aim of this study was to assess the seroconversion by different techniques after five to eight years. In 1990, 588 of 1010 asymptomatic donors were found to be seronegative by ELISA, based on an H. pylori whole-cell suspension lysate (sensitivity and specificity: 92% and 97%). In 1995 serum samples from 418 of 588 seronegative donors were collected and retested using the same antigen. 411 of 418 samples were frankly negative, and 7 donors were found to be seroconverted. This group of seven sera represents the object of the study. They were retested by ELISA and western blotting using a different antigen (NCTC). To standardize our techniques, sera from 43 H. pylori positive and 47 H. pylori negative patients according to culture, histology, urease test, and UBT were used. The cutoff for ELISA-NCTC was 0.53 AI (absorbance index) (mean value + 2 sd), and for western blotting was negativity for CagA or <10 bands (sensitivity and specificity: 95% and 96%; 98% and 81% for ELISA and western blotting respectively). According to the results obtained in 1990 and 1995, seven donors were found to be seroconverted by ELISA using sonicated antigen; in five the seroconversion was confirmed by ELISA using NCTC antigen and in two there was concordance with WB. Four of the seven donors were contacted and asked to undergo UBT and a further serum sample was drawn to be reassessed in 1998. A seroconversion was found in all four donors by ELISA, while WB and UBT confirmed the seroconversion in only three of four donors. In conclusion the in-house ELISA used performed well compared to other theoretically better serologic assays and confirmed the low seroconversion rate for H. pylori infection in adult populations living in developed countries.

A second-line anti-Helicobacter pylori therapy in patients with previously failed treatment.

TO THE EDITOR: Helicobacter pylori (H. pylori) is one of the most common bacterial infection in the world and has been associated with various gastroduodenal pathologies, from gastritis to gastric malignancies. Cure of infection has become the core of ulcer therapy, and it has been suggested that eradication could play a role even in the management of other diseases, both involving the GI tract (e.g., nonulcer dyspepsia or MALT lymphoma) (1) and not involving it (e.g., headache, Raynaud phenomenon) (2). In vivo, H. pylori eradication has turned out to be very demanding, possibly because of several different factors (e.g., peculiar echological niche, development of antibiotic resistance, components of therapeutic regimens, dosing frequency, treatment duration, and poor patient compliance (3). Currently the preferred way to cure the infection is a regimen of profound gastric acid suppression combined with two antibiotics, usually chosen among amoxycillin, clarithromycin, tetracycline, or imidazole (4). Unfortunately, patients who fail eradication after a first course of therapy are not a rarity. Similarly to other bacterial infection, the management of noncured patients can be demanding, and patients are likely to receive repeated treatments, each time with different antimicrobials, on the often unproved assumption of H. pylori resistance to the drugs first employed. This policy of exposing patients to many different drugs increases the possibility of the appearance of multiresistant strains and of adverse effects. Analysis of chemiosusceptibility shows that a variable proportion of noneradicated patients is made of subjects who have been compliant with the therapeutic regimen and who harbor strains sensible to the administered drugs (5). In these patients, the reason(s) for treatment failure is/are unclear, and it is possible that a different treatment duration and/or drag dosage could eventually lead to eradication.

Usefulness of Serology in Preendoscopic Screening

Over the last 20 years, upper gastrointestinal endoscopy has become the investigation of choice for patients with symptoms referrable to the upper gastrointestinal tract. As the increasing number of patients referred for endoscopy has led to enlarged waiting lists and medical expenses, it has been recommended that preendoscopic screening strategies might identify patients at low risk of having major pathology. These patients could avoid prompt endoscopy and might safely undergo different management. Since the recognition of the major role played by Helicobacter pylori in gastroduodenal pathology, H. pylori serological and demographical features have been proposed as part of preendoscopic screening strategies in dyspeptic patients referred to endoscopy, in an attempt to reduce endoscopic workload and medical expenses.

Symptoms and Helicobacter pylori: any link? The Italian Helicobacter pylori Study Group.

To the Editor: It is still a matter of debate whether Helicobacter pylori (H. pylori) causes symptoms in idiopathic dyspepsia because no clear indication came out from epidemiological or interventional studies (1). However, some authors observed that H. pylori infection in idiopathic dyspepsia patients is associated with epigastric pain (2, 3). A considerable number of studies has demonstrated that H. pylori strains harbouring the CagA gene are more virulent that CagA negative strains, for being more frequently associated to peptic ulcer. However, little is known as to whether CagA positive strains are associated with the occurrence of symptoms in dyspeptics. We recently conducted a large epidemiological study on the serological and histological prevalence of H. pylori infection in 3,281 patients throughout Italy undergoing endoscopy for the first time (4). At enrollment, a 10 ml blood sample was taken from each participant in the study for the determination of anti-H. pylori IgG and anti-CagA reactivity by a commercial ELISA assay (Eurospital, Trieste, Italy). Together with endoscopic diagnosis, the presence of five dyspeptic symptoms was recorded in these patients (present or absent), namely, belching, pyrosis, postprandial fullness, vomiting, and epigastric pain. After exclusion of patients with gastric cancer or borderline serology, a series of 3,163 patients with idiopathic dyspepsia, peptic ulcer, or esophagitis were available for multivariate analysis; the presence of epigastric pain was strongly associated with the diagnosis of duodenal and gastric ulcer (OR 6.03, p < 0.001; OR 2.67, p < 0.001, respectively). This association also persisted in a model adjusted for H. pylori infection. No association was observed between any of the above-mentioned symptoms and esophagitis.

Symptoms and Helicobacter pylori: Any Link|[quest]|

To the Editor: It is still a matter of debate whether Helicobacter pylori (H. pylori) causes symptoms in idiopathic dyspepsia because no clear indication came out from epidemiological or interventional studies (1). However, some authors observed that H. pylori infection in idiopathic dyspepsia patients is associated with epigastric pain (2, 3). A considerable number of studies has demonstrated that H. pylori strains harbouring the CagA gene are more virulent that CagA negative strains, for being more frequently associated to peptic ulcer. However, little is known as to whether CagA positive strains are associated with the occurrence of symptoms in dyspeptics. We recently conducted a large epidemiological study on the serological and histological prevalence of H. pylori infection in 3,281 patients throughout Italy undergoing endoscopy for the first time (4). At enrollment, a 10 ml blood sample was taken from each participant in the study for the determination of anti-H. pylori IgG and anti-CagA reactivity by a commercial ELISA assay (Eurospital, Trieste, Italy). Together with endoscopic diagnosis, the presence of five dyspeptic symptoms was recorded in these patients (present or absent), namely, belching, pyrosis, postprandial fullness, vomiting, and epigastric pain. After exclusion of patients with gastric cancer or borderline serology, a series of 3,163 patients with idiopathic dyspepsia, peptic ulcer, or esophagitis were available for multivariate analysis; the presence of epigastric pain was strongly associated with the diagnosis of duodenal and gastric ulcer (OR 6.03, p < 0.001; OR 2.67, p < 0.001, respectively). This association also persisted in a model adjusted for H. pylori infection. No association was observed between any of the above-mentioned symptoms and esophagitis.

Symptoms and Helicobacter pylori: Any Link?

To the Editor: It is still a matter of debate whether Helicobacter pylori (H. pylori) causes symptoms in idiopathic dyspepsia because no clear indication came out from epidemiological or interventional studies (1). However, some authors observed that H. pylori infection in idiopathic dyspepsia patients is associated with epigastric pain (2, 3). A considerable number of studies has demonstrated that H. pylori strains harbouring the CagA gene are more virulent that CagA negative strains, for being more frequently associated to peptic ulcer. However, little is known as to whether CagA positive strains are associated with the occurrence of symptoms in dyspeptics. We recently conducted a large epidemiological study on the serological and histological prevalence of H. pylori infection in 3,281 patients throughout Italy undergoing endoscopy for the first time (4). At enrollment, a 10 ml blood sample was taken from each participant in the study for the determination of anti-H. pylori IgG and anti-CagA reactivity by a commercial ELISA assay (Eurospital, Trieste, Italy). Together with endoscopic diagnosis, the presence of five dyspeptic symptoms was recorded in these patients (present or absent), namely, belching, pyrosis, postprandial fullness, vomiting, and epigastric pain. After exclusion of patients with gastric cancer or borderline serology, a series of 3,163 patients with idiopathic dyspepsia, peptic ulcer, or esophagitis were available for multivariate analysis; the presence of epigastric pain was strongly associated with the diagnosis of duodenal and gastric ulcer (OR 6.03, p < 0.001; OR 2.67, p < 0.001, respectively). This association also persisted in a model adjusted for H. pylori infection. No association was observed between any of the above-mentioned symptoms and esophagitis.