Carina Bengtsson

Concordance of Helicobacter pylori Strains within Families

ABSTRACT Helicobacter pylori infection is typically acquired in early childhood, and a predominantly intrafamilial transmission has been postulated. To what extent family members share the same strains is poorly documented. Our aim was to explore patterns of shared strains within families by using molecular typing. Family members of H. pylori-infected 10- to 12-year-old index children identified in a school survey were invited to undergo gastroscopy. Bacterial isolates were typed with random amplified polymorphic DNA and PCR-restriction fragment length polymorphism of the genes ureA-B, glmM, or flaA. The presence or absence of the cag pathogenicity island, a bacterial virulence factor, was determined by PCR. GelCompar II software, supplemented with visual inspection, was used in the cluster analysis. In 39 families, 104 individuals contributed 208 bacterial isolates from the antrum and corpus. A large proportion, 29 of 36 (81%) of the offspring in a sibship, harbored the same strain as at least one sibling. Mother-offspring strain concordance was detected in 10 of 18 (56%) of the families. Of 17 investigated father-offspring relations in eight families, none were strain concordant. Spouses were infected with the same strains in 5 of 23 (22%) of the couples. Different strains in the antrum and corpus were found in 8 of 104 (8%) of the subjects. Our family-based fingerprinting study demonstrates a high proportion of shared strains among siblings. Transmission between spouses seems to be appreciable. The data support mother-child and sib-sib transmission as the primary transmission pathways of H. pylori.

Seroprevalence of Helicobacter pylori Infection in Urban and Rural Vietnam

ABSTRACT Helicobacter pylori-associated diseases, such as peptic ulcer and gastric cancer, are common in Vietnam, but the prevalence of the infection is largely unknown. A validated enzyme-linked immunosorbent assay was used for seroepidemiology with 971 samples from the general population, ages 0 to 88 years, with 546 samples from an urban population (Hanoi), and with 425 samples from a poor, rural province (Hatay). The overall seroprevalence of the infection was 746 per 1,000, with a prevalence of 788 per 1,000 in Hanoi and 692 per 1,000 in Hatay (P = 0.0007). The risk for infection in the rural area of Hatay was 40% lower than in the urban population of Hanoi, with the odds ratio being 0.59 (95% confidence interval, 0.43 to 0.81). The study shows that the prevalence of H. pylori infection is high in Vietnam and especially high in a large urban area, such as the city of Hanoi.

Enzyme-Linked Immunosorbent Assay for Helicobacter pylori Needs Adjustment for the Population Investigated

ABSTRACT Helicobacter pylori infection and peptic ulcer disease are common in developing countries, e.g., Vietnam. An enzyme-linked immunosorbent assay (ELISA) for screening of patients and for seroepidemiology is a useful tool but needs to be validated in the population studied. We used in-house ELISA with sonicated Swedish and Vietnamese strains as antigens to measure immunoglobulin G antibodies after absorption with sonicated Campylobacter jejuni in sera from 270 H. pylori culture-confirmed peptic ulcer patients, 128 Swedish urea-breath test and immunoblot-positive healthy controls, and 432 Vietnamese immunoblot-positive population controls. Sonicated whole-cell antigen based on the local strains showed a significantly better performance. Immunoblot-positive peptic ulcer patients had significantly higher antibody concentrations than immunoblot-positive population controls, necessitating a lower cutoff level if serology is used for screening or epidemiological purposes. The study shows that the parameters of ELISA for H. pylori need to be adjusted for the population being investigated.

Evaluation of a Novel Monoclonal-Based Antigen-in-Stool Enzyme Immunoassay (Premier Platinum HpSA PLUS) for Diagnosis of Helicobacter pylori Infection in Vietnamese Children

Background: Helicobacter pylori infection is difficult to diagnose in children, especially in developing countries where noninvasive methods such as urea breath test are often not available. We evaluate the sensitivity and specificity of a new monoclonal antibody‐based antigen‐in‐stool enzyme immunoassay (Premier Platinum HpSA PLUS) for diagnosis of H. pylori infection in Vietnamese children.

Eradication of Helicobacter pylori in Children in Vietnam in Relation to Antibiotic Resistance

Background:  Low Helicobacter pylori eradication rates are common in pediatric trials especially in developing countries. The aim of the study was to investigate the role of antibiotic resistance, drug dosage, and administration frequency on treatment outcome for children in Vietnam.

Evaluation of Two Triple-Therapy Regimens with Metronidazole or Clarithromycin for the Eradication of H. pylori Infection in Vietnamese Children: a Randomized, Double-Blind Clinical Trial

Background:  Eradication of Helicobacter pylori infection in children in developing countries needs further investigations upon which to base treatment recommendations. The aim of the study was to compare two 2‐week triple therapies in a randomized double‐blind trial.

Diagnosis ofHelicobacter pylori

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

Age as risk factor for Helicobacter pylori recurrence in children in Vietnam.

The determinants for acquisition of Helicobacter pylori infection remain incompletely understood. The study aim was to investigate risk factors for recurrence in children in Vietnam during 1 year immediately following successful H. pylori eradication.

Capture EIA for determination of ige to diphtheria and tetanus toxins in comparison to RIA

A capture IgE assay in EIA with diphtheria toxin and tetanus toxoid as model systems was developed and evaluated in relation to RIA in a DT booster study. The EIA and the RIA gave very similar results, although the EIA determined IgE over a wider range of concentrations, without interference by other subclasses. The comparison to the capture EIA indicated that the RIA gave more reliable results when a toxin as antigen. Weak correlations between local side effects and IgE responses and differences between vaccine groups were noted by RIA but not by EIA, which correlated better with the clinical findings.