Mikael Sörberg

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.

The Diagnostic Value of Enzyme Immunoassay and Immunoblot in Monitoring Eradication of Helicobacter pylori

55 patients with severe ulcer disease and H. pylori infection, successfully treated with antimicrobials, were followed-up with repeated blood samples for up to 32 months. Sera were analysed by enzyme immunoassay (EIA) for IgG and IgA antibodies and by IgG immunoblot. The EIA for IgG antibodies showed a high sensitivity (100%), while IgA antibodies above the cut-off level were found in 55% of the patients. At a median of 77 days after onset of treatment, approximately 50% of the patients showed a significant decrease (> or = 50%) of IgG or had titres below the cut-off level. All patients but 1 had a significant decrease of IgG after 6-12 months. The decrease was slower for IgA. The H. pylori-specific 116 kDa and 19.5 kDa bands were found in all pre-treatment samples, but the decrease in median intensity of the bands was slower than for the IgG EIA. In the 32-months post-treatment samples, both bonds had an intensity still above 50% of the pre-treatment value. The study showed that the IgG EIA is a useful method for monitoring eradication of H. pylori. Immunoblot can detect previous H. pylori infection in EIA negative Individuals.

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.

Capsular types and antibiotic susceptibility of invasive Streptococcus pneumoniae among children in Sweden.

To investigate the serotype distribution and antibiotic susceptibility patterns 204 isolates of Streptococcus pneumoniae obtained from blood or cerebrospinal fluid (CSF) of children < or = 18 y of age were collected from 19 clinical microbiological laboratories in Sweden during the years 1998-2001. 166 isolates were from blood only, and 38 isolates were from CSF. The most common serotypes found were 6B, 1, 7F, 14, 18C, 19F, 6A, 4, 23F, 9V and 19A, in descending order of frequency. During the study period serotype 6B increased in frequency from 14.3% in 1998 to 28.3% in 2001 and serotype 1 decreased simultaneously from 20.4% to 9.4%. Serotype 1 was the most common serotype among children > or = 2 y of age or older, but was not found among children < 2 y of age. The potential coverage rate for the heptavalent pneumococcal conjugate vaccine varied between 53 and 68% during the studied years, and was higher for children < 2 y of age (74%) than for older children (51%). The majority of isolates were susceptible to penicillin and other antibiotics tested.

Helicobacter pylori eradication and peptic ulcer healing: the impact of deleting the proton pump inhibitor and using a once-daily treatment.

Aim: To compare cheaper and simpler once‐daily regimens, with and without a proton pump inhibitor, with standard, twice‐daily, triple therapy.

The importance of the level of metronidazole resistance for the success of Helicobacter pylori eradication

Aims : To evaluate the role of antibiotic susceptibility for the treatment outcome of proton pump inhibitor‐dependent and independent Helicobacter pylori eradication regimens.

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.

Antibiotic Use and Escherichia coli Resistance Trends for Quinolones and Cotrimoxazole in Sweden

Resistance rates among Escherichia coli isolates for quinolones and cotrimoxazole were analysed at 12 Swedish hospitals, and compared with antibiotic use. Resistance figures for E. coli were retrieved from the diagnostic microbiology service databases for the period 1989-99, and antibiotic sales figures were obtained from the National Corporation of Swedish Pharmacies. At the 2 university teaching hospitals included, norfloxacin resistance of E. coli increased significantly (p< 0.001) from 0% to 2.7% and 2.5%, respectively. Ciprofloxacin resistance increased (p < 0.001) in parallel. Quinolone use increased until 1992; subsequently, sales have remained at a stable level. The increase in norfloxacin and ciprofloxacin resistance started relatively simultaneously in all hospitals, around 1991. Cotrimoxazole resistance has also been increasing significantly in most hospitals, in spite of decreasing sales of cotrimoxazole and trimethoprim. Similar trends could be seen in blood isolates from the same hospitals for the period 1991-98. Clinical laboratory data are subject to bias but surveillance over longer periods of time provides a useful method for detecting trends in increasing resistance and therefore functions as a resistance warning system.

Long-term Antibiotic Resistance Surveillance of Gram-negative Pathogens Suggests that Temporal Trends can be Used as a Resistance Warning System

Antibiotic resistance among Gram-negative bacteria and antibiotic consumption were investigated at the Karolinska Hospital, Stockholm, Sweden over a 12-y period. The investigation showed an increase in ciprofloxacin resistance of Escherichia coli from 0% in 1991 to 7% in 1997 and to 11% in 1999. Resistance among Pseudomonas aeruginosa isolates to ciprofloxacin increased from 2.5% in 1991 to 9.0% in 1997 and to 13% in 1999. Resistance levels for norfloxacin showed the same high statistical significance in terms of the temporal trend. A more detailed analysis showed higher resistance against norfloxacin in specific wards. Relationships between antibiotic use and antibiotic susceptibility showed different patterns. The increased ciprofloxacin resistance of E. coli and P. aeruginosa during the study period was paralleled by an increased consumption of quinolones. During the 12-y study period the total use of cephalosporins increased 2.5-fold, while the levels of E. coli resistance to cefuroxime and cefotaxime remained stable. A third pattern was seen with trimethoprim-sulfamethoxazole, namely increasing resistance of E. coli as the use of trimethoprim-sulfamethoxazole declined. The analysis of resistance levels and antibiotic consumption in the present study suggests different mechanisms for the increased resistance. The significant trend of increased resistance to antibiotics over time constitutes an important warning system.