Helicobacter pylori reinfection is virtually absent after successful eradication

Recurrence of Helicobacter pylori infection and the affecting factors: A follow-up study

OBJECTIVE

Recurrence of Helicobacter pylori (H. pylori) infection weakens the protective effect and long-term prognosis of eradication. With the widespread therapies, decreasing prevalence of H. pylori infection and improvement in living conditions, the recurrence of H. pylori infection may present with new features. We conducted this prospective, large-scale, multicenter follow-up study to determine the recurrence rate of H. pylori infection and its affecting factors.

METHODS

A total of 827 patients receiving successful H. pylori eradication in our previous randomized controlled trial were enrolled. ¹³ C-urea breath test (UBT) was repeated one year after the eradication therapy to determine its recurrence. Moreover, a questionnaire survey was performed to explore the potential factors affecting the recurrence.

RESULTS

A total of 743 patients completed ¹³ C-UBT (follow-up rate 89.8%), and the result was positive in 13 patients one year after eradication therapy, with an annual recurrence rate of 1.75% (95% confidence interval [CI] 0.81-2.69%). Six hundred and ninety-two patients (13 with recurrence and 679 without recurrence) returned their questionnaires, with a response rate of >80%. Multivariate analysis revealed that peptic ulcer (odds ratio [OR] 3.385, 95% CI 1.016-11.274), close contact with individuals having H. pylori infection (OR 4.231, 95% CI 1.201-14.911), and hospitalization (OR 9.302, 95% CI 2.441-35.440) were independent risk factors of H. pylori infection recurrence.

CONCLUSIONS

The recurrence of H. pylori infection one year after eradication therapy is low in urban population of China. Peptic ulcer, contact history with individuals having H. pylori infection and hospitalization are risk factors.

The diagnosis and treatment of Helicobacter pylori infection in Arctic regions with a high prevalence of infection: Expert Commentary

Helicobacter pylori infection is a major cause of peptic ulcer and is also associated with chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, and adenocarcinoma of the stomach. Guidelines have been developed in the United States and Europe (areas with low prevalence) for the diagnosis and management of this infection, including the recommendation to ‘test and treat’ those with dyspepsia. A group of international experts performed a targeted literature review and formulated an expert opinion for evidenced-based benefits and harms for screening and treatment of H. pylori in high-prevalence countries. They concluded that in Arctic countries where H. pylori prevalence exceeds 60%, treatment of persons with H. pylori infection should be limited only to instances where there is strong evidence of direct benefit in reduction of morbidity and mortality, associated peptic ulcer disease and MALT lymphoma and that the test-and-treat strategy may not be beneficial for those with dyspepsia.

Prevalence of Helicobacter pylori and its recurrence after successful eradication in a developing nation (Morocco)

INTRODUCTION

In developed countries, reinfection after successful eradication of Helicobacter pylori appears unusual. High prevalences of H. pylori in developing countries may result in high reinfection rates. In Morocco, published studies regarding the prevalence of H. pylori are limited, and to our knowledge, there are no data regarding the reinfection rate of H. pylori after successful treatment.

AIM

The aim of this study was to determine the prevalence of H. pylori in our area, and the reinfection rate at 6 months and 1 year of follow-up after successful eradication.

METHODS

Consecutive patients with investigated ulcer or non-ulcer dyspepsia were prospectively enrolled in the Hassan II University Hospital of Fez. Patients with H. pylori infection were treated with a 1-week triple therapy or 10 day sequential therapy. Those tested urea breath test negative after 3 months of treatment were followed prospectively with repeated urea breath test at 6 months and 1 year. H. pylori status at endoscopic examination was determined by rapid urease test, histology, and culture.

RESULTS

Four hundred and twenty-nine patients were enrolled in the study, among them 324 patients (75.5%) presented with H. pylori infection. Two hundred and fifty-six (83.3%) patients had successfully eradicated H. pylori following treatment, among them, two patients (0.8%) were reinfected with H. pylori over 12 months. The rate of reinfection was 0.42% in the first 6 months and of 0.45% in the first year of the study.

CONCLUSION

The results of the present study demonstrate that firstly, prevalence of H. pylori is high (75.5%) in our area, secondly as in developed countries, there is a low (0.8%) but continuous risk of H. pylori infection in adulthood. A different approach for follow-up after H. pylori eradication is probably needed in patients of developing countries, since reinfection prevalence is different between countries.

Review article: 'true' re-infection of Helicobacter pylori after successful eradication--worldwide annual rates, risk factors and clinical implications

BACKGROUND

The incidence of 'true' re-infection with Helicobacter pylori after successful eradication remains uncertain.

AIM

To determine the worldwide rates, risk factors and clinical implications of 'true' re-infection of Helicobacter pylori. 'True' re-infection of H. pylori is defined as the situation where tests for H. pylori infection, which were negative for 12 months after eradication, become positive again at a later stage.

RESULTS

Thirty six studies were identified through a literature search to be able to produce annual rates of 'true' re-infection, and data from 33 original articles were considered reliable and adequate in the further review. Generally, the reported rates varied from 0% to 23.4% in adults and from 1.9% to 9.6% in children. Most studies from developed countries reported rates of less than 1%, whereas relatively higher rates were reported in most of the developing countries. Small sample sizes included in the studies appeared to be associated with increased re-infection rates. Interfamilial transmission is the major cause of re-infection, although iatrogenic re-infection through contaminated endoscopic equipment has been reported.

CONCLUSION

Helicobacter pylori re-infection is not a concern in a clinical setting, especially in the developed world; however, caution must be exercised in most developing countries.

Long-term follow up of Helicobacter pylori IgG serology after eradication and reinfection rate of H. pylori in South Korea

BACKGROUND

Serology is widely used for epidemiologic research of Helicobacter pylori. However, there is limited information on the long-term follow up of H. pylori titers after eradication. In addition, it is presumed that the reinfection rate decreases as the H. pylori infection rate decreases. The aim of this study was to investigate the long-term follow up of H. pylori IgG, and to evaluate the reinfection rate of H. pylori in Korea.

METHODS

Among 247 patients, who were enrolled during 2003-07, 185 patients with invasive H. pylori test positive received proton pump inhibitor-based triple therapy, and follow-up H. pylori testing, including histology, CLOtest, culture, and serology, were evaluated 2, 10, and 18 months after H. pylori eradication.

RESULTS

The initial H. pylori IgG optical density (OD(450 nm)), 2.06, gradually decreased to 0.63 (67% reduction) at 18 months after H. pylori eradication. The seroreversion rate was 5, 10, and 45% at 2, 10, and 18 months after H. pylori eradication, respectively. The recrudescence of H. pylori was 3.49%, and the annual reinfection rate was 2.94% per year. H. pylori IgG titers abruptly increased in cases with recrudescence and reinfection, and correlated with the results of the invasive H. pylori tests.

CONCLUSION

The results of this study showed that H. pylori IgG serology could be used for the determination of reinfection of H. pylori, but not for the diagnosis of H. pylori eradication. The reinfection rate of H. pylori, in Korea, was found to be very low, 2.94% per year.

Helicobacter pylori recurrence and infection rate in Israeli adults

INTRODUCTION

In developing countries the recurrence rate of Helicobacter pylori after successful eradication therapy is as high as 42%, while in developed countries it is estimated to be less than 3%. Such figures are very important in terms of determining clinical strategy and outcome.

AIM

To estimate the recurrence rate of H. pylori in Israel using the database of the "Central H. Pylori Laboratory of Clalit Health Services".

METHODS

The database was searched for patients who had undergone the [(13)C]-urea breath test ([(13)C]-UBT) for validation of the successful eradication of H. pylori or for evaluation of dyspepsia 7 years previously and for whom the result had been negative. These patients were invited to participate in the trial, fill a symptom questionnaire and undergo another [(13)C]-UBT.

RESULTS

A In total, 65 patients participated; of these, 26 patients had tested negative in the first( 13)CUBT, indicating the successful eradication of H. pylori (Group A), and 39 had been tested for dyspepsia (Group B). One patient in each group had a positive [(13)C]-UBT - 3.84% in Group A and 2.56% in Group B (non-significant difference, NS). The mean annual H. pylori recurrence rate was calculated to be 0.55% and 0.37% in Group A and Group B patients, respectively (NS).

CONCLUSION

Our results shown a very low re-infection or new infection rates in Israeli adults and are in line with other trials in developed countries; they do not support the a retesting program for patients after a successful eradication therapy.

H pylori recurrence after successful eradication

Recurrence of H pylori after eradication is rare in developed countries and more frequent in developing countries. Recrudescence (recolonization of the same strain within 12 mo after eradication) rather than reinfection (colonization with a new strain, more than 12 mo after eradication) is considered to be responsible for most of the cases. This observation was confirmed only in developed countries, while in developing countries a recent meta-analysis demonstrated a high rate of reinfection. The proportion of H pylori annual recurrence was 2.67% and 13.00% in developed and developing countries, respectively. Nested meta-analysis (only cases with a longer follow-up and a negative ¹³CUBT a year after eradication) revealed annual recurrence rate of 1.45% [relative risk (RR), 0.54] and 12.00% (RR, 0.92) in developed and developing countries, respectively. These findings support the notion that in developed countries many cases of recurrence are due to recrudescence within the first year after eradication, with a 46% drop in the recurrence rate after the first year post eradication, while in developing countries reinfection is more pronounced, and continue at the same rate since eradication. A different approach for follow-up after H pylori eradication is probably needed in patients of developing countries, since reinfection is highly prevalent.

Helicobacter pylori recurrence in developed and developing countries: meta-analysis of 13C-urea breath test follow-up after eradication

OBJECTIVE

Recurrence of Helicobacter pylori infection after eradication is rare in developed countries and more frequent in developing countries. Most recurrent cases are attributed to recrudescence (recolonization of the same strain within 12 months) rather than to reinfection (colonization with a new strain after more than 12 months). The aim of the study was to analyze recurrence rates in developed and developing countries and to deduce the relative roles of recrudescence and reinfection.

METHODS

The PubMed database was searched up to January 31, 2007 using the keywords "Helicobacter pylori" or "H. pylori" and "recurrence" or "recrudescence," or "reinfection." Only prospective case studies in adults that used the (13)C-urea breath test ((13)CUBT) were included. Meta-analyses were performed with statdirect Statistical software, version 2.6.1, StatsDirect Ltd, Chesire, UK.

RESULTS

The literature search yielded 10 studies of H. pylori recurrence in developed countries (3014 patients followed for 24-60 months) and 7 studies in developing countries (2071 patients followed for 12-60 months). The calculated annual recurrence rates were 2.67% and 13.00%, respectively. Nested meta-analysis of cases with a longer follow-up after eradication revealed an annual recurrence rate of 1.45% (RR 0.54) in developed countries and 12.00% (RR 0.92) in developing countries.

CONCLUSIONS

The similarity of the annual recurrence rates during the first year after eradication and the annual recurrence rates in the second year after successful eradication in developing countries supports reinfection as the main cause in the second period. Therefore, a different approach for follow-up of H. pylori eradication may be needed between developed and developing countries.

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori Infection

SUMMARY

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori .

Pathogenesis of Helicobacter pylori infection

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

High rate of Helicobacter pylori reinfection in children and adolescents

AIMS

Primary Helicobacter pylori infection occurs predominantly in childhood. The aims of this study were to establish the rate of H. pylori reinfection after successful eradication in children and adolescents and to determine the risk factors associated with reinfection.

PATIENTS AND METHODS

This retrospective study involved 45 children (20 girls, 25 boys) who met the following criteria: eradication of H. pylori confirmed at least 4 weeks after the completion of therapy, and the search for reinfection at least one year after control of eradication of H. pylori. Demographic data, socioeconomic status and living conditions were recorded.

RESULTS

Forty-five children aged 1.2-17.6 years (median, 10.9 years) at the time of H. pylori treatment were reviewed 1 to 9 years after H. pylori eradication. Eight children (18%) had been reinfected (5.4% to 6% per patient-year). Six of 25 (24%) children older than 10 years at the time of diagnosis became reinfected. None of the studied risk factors was associated with reinfection. However, having a sibling younger than 5 years was found in four of seven (57%) reinfected children versus five of 24 (21%) nonreinfected children (p = .08).

CONCLUSION

Children become reinfected more frequently than adults. Adolescents become reinfected, whereas acquisition of primary H. pylori infection occurs predominantly in early childhood. Close contact with young children, especially siblings, younger than 5 years could be a more important risk factor than the age of the patient at the time of treatment for the high rate of reinfection in childhood.

Long-term outcomes after Helicobacter pylori eradication with second-line, bismuth-containing quadruple therapy in Korea

OBJECTIVES

To determine the long-term outcomes in terms of Helicobacter pylori and ulcer recurrence after second-line eradication with bismuth-containing quadruple regimens in Korea.

METHODS

Sixty-seven patients with peptic ulcer disease after successful eradication using second-line quadruple therapies were prospectively followed up 1 month after treatment and then every 6 months or when dyspeptic symptoms reappeared to ascertain H. pylori and ulcer status.

RESULTS

Three patients were lost during follow-up. The median duration of follow-up of the remaining 64 patients was 26.8 months. H. pylori recurrence occurred in 11 of these 64 patients (17.2%), giving a calculated reinfection rate of 6.0% per patient-year. Only one of the 11 patients was reinfected by 12 months after treatment completion. Four of 11 patients (36.4%) who became reinfected experienced peptic ulcer recurrence, but none of 53 patients who were not reinfected experienced recurrence. No evidence was obtained to indicate that the reinfection rate depended on the age, sex, ulcer location, or eradication regimens. The relapse of dyspeptic symptoms was the only factor predictive of H. pylori recurrence.

CONCLUSION

This study suggests that the recurrence rate of H. pylori at 1 year after second-line, bismuth-containing quadruple therapy is low, but the annual reinfection rate is as high as 6%. Surveillance for H. pylori reinfection facilitating peptic ulcer recurrence may be warranted even after a second eradication, especially when dyspeptic symptoms reappear in Korea.

Long-term study of re-infection following successful eradication of Helicobacter pylori infection

BACKGROUND

'Re-infection' with Helicobacter pylori after eradication has been estimated to occur in 0-14% of patients, although most so-called 're-infections' occur within the first year following 'eradication' and many may actually be due to recrudescence of a temporarily suppressed infection.

AIM

To study the true re-infection rate, we have studied re-infection rates after eradication therapy by excluding the first year's data, minimizing the possible confounding effect of recrudescence.

METHODS

All patients tested for H. pylori infection following eradication therapy between 1987 and 2004 were evaluated. Testing was carried out by urea breath test and gastric biopsy. Patients were included if they were found to be negative for H. pylori infection by testing at least 1 year following eradication and underwent at least one further test for H. pylori.

RESULTS

1162 patients met the inclusion criteria with median post-eradication follow-up of 3 years (1.5-14) including 4668 tests; 3319 years of follow-up were analysed. Thirteen cases of re-infection occurred (re-infection rate 0.4% per year).

CONCLUSIONS

This large study of H. pylori re-infection avoided cases of recrudescence by excluding the first post-eradication year. True re-infection is probably less common than previously thought.

Reinfection after successful eradication of Helicobacter pylori: a 2-year prospective study in Alaska Natives

BACKGROUND

Limited information exists regarding risk factors for reinfection after cure of Helicobacter pylori infection.

AIM

To determine the 2-year reinfection rate of H. pylori in a cohort of urban Alaska Natives.

METHODS

Participants over 18 years of age undergoing oesophagogastroduodenoscopy had (13)C urea breath test, culture, CLOtest and histology performed. Those diagnosed with H. pylori who tested urea breath test-negative at 8 weeks after treatment were followed prospectively at 4 months, 6 months, 1 year and 2 years. Subjects experiencing H. pylori reinfection as defined by a positive urea breath test were compared with those who did not become reinfected using univariable and multivariable analysis. Risk of reinfection over time was estimated by the Kaplan-Meier method.

RESULTS

Helicobacter pylori reinfection occurred in 14 of 98 subjects successfully treated. The cumulative reinfection rate was 5.1% (95% CI: 0.7%-9.5%) at 4 months, 7.2% (2.0-12.3%) at 6 months, 10.3% (4.2-16.3%) at 1-year and 14.5% (7.5-21.6%) at 2 years. In multivariable analysis, a history of previous peptic ulcer disease or presence of ulcer at time of study oesophagogastroduodenoscopy were the only risk factors associated with reinfection (P = 0.01).

CONCLUSIONS

Based on the findings from our study, subjects with a history of or current peptic ulcer disease should be followed, after successful treatment for H. pylori, with periodic urea breath test to detect reinfection, as reinfection would put them at high risk for ulcer recurrence.

Long-term follow-up of gastric MALT lymphoma after Helicobacter pylori eradication

PURPOSE

Cure of infection induces remissions in most patients with early stage Helicobacter pylori- (Hp) positive gastric MALT (mucosa-associated lymphoid tissue) lymphoma (GML). We tracked the long-term stability of remissions in this prospective, multicenter trial.

PATIENTS AND METHODS

In 120 patients with stage I(1E) disease, we performed sequential endoscopic-bioptic follow-up after Hp eradication and polymerase chain reaction of the rearranged immunoglobulin heavy chain gene. The status of t(11;18) was assessed in 65 patients.

RESULTS

Median follow-up was 75 months (range, one to 116). Five-year survival was 90%. Eighty percent of patients (96 of 120) achieved complete histologic remission (CR). Eighty percent of CRs are in continuous complete histologic remission (CCR). Three percent of CR patients (three of 96) relapsed and were referred for alternative treatment. Seventeen percent of CR patients (16 of 96) showed histologic residual disease (RD) during follow-up; a watch-and-wait strategy was applied, and all entered into a second CR. After a median follow-up of 63 months, 14 of 52 analyzed patients reaching CR showed ongoing B-cell monoclonality. Fifteen percent of GMLs were t(11;18) positive. Both t(11;18) and ongoing monoclonality were associated with a significantly higher risk for no response or relapse (P =.004, P =.007), but also present in patients in CCR. Early gastric cancer was diagnosed in three cases during follow-up.

CONCLUSION

Cure of Hp infection results in CCR in most patients. Histologic RD, B-cell monoclonality, and t(11;18) were present in a considerable number of CR patients. A watch-and-wait strategy is justified when close follow-up is guaranteed.

Long-term follow-up after eradication of Helicobacter pylori with omeprazole, clarithromycin, and tinidazole (OCT regimen) in a Japanese population

BACKGROUND

The long-term benefit of Helicobacter pylori eradication treatment that includes metronidazole on peptic ulcer disease in Japan is unclear. We investigated the rate of H. pylori re-infection and ulcer relapse after H. pylori eradication.

MATERIALS AND METHODS

A total of 266 patients with endoscopically confirmed peptic ulcer disease and H. pylori infection were treated with triple therapy of omeprazole 40 mg (20 mg b.i.d.), clarithromycin 800 mg (400 mg b.i.d.), and tinidazole 1000 mg (500 mg b.i.d.) for 7 days. Endoscopy with gastric biopsy was performed before and 1 month, 6 months, 1.5 years, and 3.5 years after therapy. H. pylori status was determined by H. pylori culture, rapid urease test, and histopathology. 13C-urea breath test was done at 6 months after eradication therapy. Treatment was deemed successful when all tests were negative at 6 months after therapy by endoscopic biopsy.

RESULTS

Successful H. pylori eradication was achieved in 262/266 (98.5%) patients with peptic ulcer. Total relapse of peptic ulcer occurred in 8/262 (3%) patients after eradication, with 3/262 (1.1%) occurring within 1.5 years after treatment and 5/262 (1.9%) within 3.5 years. All relapsed patients were found to be H. pylori-positive at the time of relapse. Of the 262 patients who experienced eradication, 20 (7.6%) were subsequently re-infected, six (2.3%) within 1.5 years and 14 (5.3%) within 3.5 years.

CONCLUSION

Triple therapy with omeprazole, clarithromycin, and tinidazole (OCT) is useful for H. pylori eradication in Japan, but there is an appreciable re-infection rate in this population.

The recurrence of Helicobacter pylori infection: incidence and variables influencing it. A critical review

The rate of H. pylori recurrence after eradication of the microorganism seems to be relatively low, at least in developed countries, where the mean annual reinfection rate is of approximately 3% per patient-year of follow-up, although the risk of reinfection in some developing regions is considerably higher. Several findings suggest that recrudescence rather than reinfection is likely to be responsible for most cases of recurrence: (i) the recurrences decrease with time and decline sharply after the first year, and (ii) studies using molecular fingerprinting techniques (polymerase chain reaction [PCR]) confirm that the identified microorganisms (before and after therapy) are usually genetically identical. The lower the efficacy of an antibiotic therapy, the greater the likelihood that recurrence occur, again suggesting that in these cases temporary "clearance" has been achieved rather than true eradication. The value of the (13)C-urea breath test after treatment is higher in those patients who suffer a recurrence; therefore, selection of a lower cut-off value may be helpful to maintain the diagnostic accuracy of posttreatment breath test, and thus preventing recrudescences. The observation of a pattern of histological (active) gastritis without the concomitant finding of H. pylori must raise the suspicion of a diagnostic error. Some studies suggest that recurrence is relatively infrequent, even if the patient's spouse is H. pylori-positive, suggesting that the patient's partner does not act as a reservoir for the reinfection. However, other investigators achieve contrary results, although a common exogenous source of H. pylori (for both partner's infection and patient's reinfection) cannot be ruled out. The oral cavity may be a potential source for recrudescence of gastric infection after successful therapy. When peptic ulcer reappears (sometimes with bleeding recurrence) or gastric MALT (mucosa-associated lymphoid tissue) lymphoma relapses after previous H. pylori eradication, recolonization of the gastric mucosa by the organism has almost always occurred.

Long-term follow-up of Helicobacter pylori eradication therapy in Vietnam: reinfection and clinical outcome

AIM

To assess the long-term Helicobacter pylori reinfection rates, as well as the clinical outcome in peptic ulcer disease patients in Vietnam.

METHOD

At a 1-year evaluation of H. pylori eradication treatment in 226 peptic ulcer patients, long-term H. pylori status was assessed with serology and/or culture, peptic ulcer status by gastroscopy, and DNA-fingerprinting performed with random amplified polymorphic DNA and restriction fragment polymorphism.

RESULT

Follow-up was performed a mean 11 months after the post-treatment evaluation on day 30 after beginning of treatment. The overall reinfection rate was 23.5%, with 58.8% of the strains being identical to the pre-treatment isolates and 41.2% being different. Peptic ulcer was found in 22.9% of the reinfected patients and in 6.3% of the non-reinfected. At the long-term follow-up of successful eradication cases, 89.8% of the patients were free of peptic ulcer disease. The corresponding result was 58.7% in patients in whom H. pylori eradication failed.

CONCLUSION

Following successful H. pylori eradication, reinfection with H. pylori in patients in Vietnam was found to be higher than in industrialized countries but the long-term recurrence of peptic ulcer disease was still low. Helicobacter pylori eradication treatment is therefore of value also in developing countries as the rate of peptic ulcer disease was low at the 1-year follow-up.

Helicobacter pylori reinfection rate 3 years after successful eradication

BACKGROUND AND AIM

Helicobacter pylori (HP) infection is one of the most prevalent human infections and has been implicated as a predisposing factor in gastric cancer, chronic active gastritis, duodenal ulcer, gastric ulcer and gastric lymphoma. Reinfection after successful eradication is quite uncommon in adults. In the only study carried out in Iran, a reinfection rate of 19.1% after 1 year has been reported. We studied the rate of reinfection 3 years after successful HP eradication.

METHODS

All patients who had undergone HP eradication 3 years before the study and had successful eradication verified by a negative (14)C urea breath test (UBT) 1 year after eradication were invited to complete a questionnaire and undergo another UBT. In addition, spouses and the offspring of those testing positive were offered an UBT.

RESULTS

Ninety-eight patients were enrolled (49% male). Mean age was 44 +/- 13 years (range: 18-75 years). Twenty patients (20.4%) had a positive UBT. Epigastric burning (25%vs 69%) and pyrosis (50%vs 67%) were seen less commonly in those who were HP free at 3 years compared to those who tested positive for HP.

CONCLUSIONS

According to our data, in our region the HP reinfection rate is 20.4% 3 years after successful eradication.

Long-term recurrence rate after treatment of Helicobacter pylori infection in children and adolescents in Estonia

BACKGROUND

Helicobacter pylori infection is common in Estonia: 87% of adults and 56% of children aged 9-15 years have been found to be H. pylori seropositive. The aim of this study was to evaluate the long-term recurrence rate after treatment in children and adolescents in a setting of high H. pylori prevalence.

METHODS

All children (n = 27) who underwent gastroscopy at the Children's Clinic of Tartu University Clinics during 1993--95 and in whom H. pylori infection was verified by histological examination and rapid urease test and who had completed a treatment course against H. pylori infection were invited for a post-treatment follow-up endoscopy 4-6 weeks after completion of therapy (1st follow-up visit) and to the follow-up control by [13C]-urea breath test in 1997 (2nd follow-up visit) and 2002 (3rd follow-up visit).

RESULTS

Recurrence of H. pylori infection occurred in I patient out of 16 at the 2nd follow-up visit (mean 17.8+/-7.1 months after treatment), and in 5 patients out of 15 at the 3rd follow-up visit (mean 6.6+/-0.9 years after treatment). The recurrence rate calculated for the period between the 1st and the 2nd follow-up visits was 4.2% per patient-year, and between the 2nd and the 3rd follow-up visits the rate was 7.6% (95% CI 2.5%-17.6%) per patient-year. The recurrence rate calculated for the whole follow-up period was 6.7% (95% CI 2.5%-14.5%) per patient-year.

CONCLUSION

The post-treatment recurrence rate of H. pylori infection in children and adolescents is higher in Estonia than in low prevalence settings.

DNA typing for Helicobacter pylori isolates from eradication-failed patients: comparison of the isolates before and after therapy

BACKGROUND

Failure of Helicobacter pylori eradication occurs frequently despite use of multiple microbial agents.

AIM

We aimed to study differences between H. pylori strains isolated before and after eradication failure.

METHODS

We treated 87 patients with peptic ulcer using triple therapy consisting of omeprazole plus combinations of clarithromycin, amoxicillin, or metronidazole. We studied the status of cagA, vacA, and iceA by PCR, and examined the differences in H. pylori isolates by pulsed-field gel electrophoresis and arbitrary primer polymerase chain reaction. The minimum inhibitory concentration of clarithromycin, amoxicillin, or metronidazole was determined by an agar dilution method.

RESULTS

Eradication therapy failed in 12 patients (14%); H. pylori isolates were obtained from all of these both before and after therapy. After eradication therapy, 10 patients were colonized with the same strain as before therapy, while the other two patients were colonized with different strains from those before therapy. In the former group, one isolate changed from metronidazole-sensitive to -resistant, one changed from clarithromycin- and metronidazole-sensitive to -resistant, and four were resistant to clarithromycin or metronidazole both before and after therapy. The other four isolates remained sensitive to clarithromycin and metronidazole after therapy. In the two patients who yielded apparently different isolates after therapy, they changed from clarithromycin- and metronidazole-sensitive to -resistant.

CONCLUSION

Eradication of H. pylori by first-line therapy is an important goal in the treatment of H. pylori-positive peptic ulcer, and that appropriate antimicrobial sensitivity testing should be conducted in patients with eradication failure.

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.

METHODS

In a placebo-controlled clinical study of peptic ulcer patients with H. pylori infection, patients were randomized to receive lansoprazole, clarithromycin and tinidazole twice-daily, clarithromycin and tinidazole once-daily with lansoprazole or with placebo. Helicobacter pylori status was assessed by culture and antibiotic susceptibility by E-test minimal inhibitory concentration (MIC) in 205 clinical isolates.

RESULTS

Primary resistance to clarithromycin and metronidazole was 1 and 76%, respectively. In metronidazole susceptible strains eradication rates were similar at > 90% for all treatment groups (P = 0.49). With low-level metronidazole resistance (4 microg/mL < MIC < 256 microg/mL), eradication rates were similar at >75% (P = 0.80). The major difference was found at high-level metronidazole resistance (MIC >or= 256 microg/mL) with 95%, 58% and 21% eradication in the lansoprazole, clarithromycin and tinidazole twice-daily, lansoprazole, clarithromycin and tinidazole once-daily and placebo, clarithromycin and tinidazole once-daily groups, respectively (P < 0.001).

CONCLUSION

In the absence of antibiotic resistance, a once-daily therapy of only clarithromycin and tinidazole can achieve a high rate of H. pylori eradication. Such a combination could offer a simpler and cheaper treatment option for developing countries. The standard, twice-daily proton pump inhibitor-based triple therapy was shown to be efficient in H. pylori eradication even in the presence of high-level metronidazole resistance.

Pharmacoeconomics of gastrointestinal drug utilisation prior and post Helicobacter pylori eradication

BACKGROUND

Eradication of Helicobacter pylori prevents recurrence of peptic ulcer. In pharmacoeconomic analyses it is often presumed that after successful eradication no more gastrointestinal drugs are used. We investigated this presumed positive monetary effect using General Practitioners prescribing data, including information in diagnosis.

METHODS

From the RNG-database we identified patients with a H. pylori eradication in the years 1997-2000. H. pylori eradication was defined as a prescription of two antibiotics and one gastrointestinal drug on the same day. Patients were divided into a group with diagnosed ulcers and a group without diagnosed ulcers. Gastrointestinal drug costs were calculated for 4 months prior to eradication and 9-12 months post eradication. For comparison costs in all periods were expressed per patient per period. For statistical analysis the paired t-test was used.

RESULTS

One hundred and two patients were eligible for evaluation. Of these patients 35 had a diagnosed ulcer and 67 had not. Generally the number of patients on gastrointestinal drugs decreased (61% prior vs. 33% post), however, the drug costs did not change (Euro 33 prior vs. Euro 34 post). Costs for proton pump inhibitors increased post eradication (Euro 14 prior vs. Euro 28 post). The ulcer and nonulcer group showed similar results.

CONCLUSION

Helicobacter pylori eradication is thought to be cost effective, however, we did not find a decrease in costs for all gastrointestinal drugs. There may be a great pharmacoeconomical advantage when it is possible to predict which patients are more likely to 'fail' eradication therapy.

Is the recurrence of Helicobacter pylori infection after eradication therapy resultant from recrudescence or reinfection, in Japan

BACKGROUND

Reinfection of Helicobacter pylori after eradication is rare in developed countries but most often occurs within 1 year. In the present study, we attempted to differentiate between reinfection and recrudescence of H. pylori strains between 6 months and 6 years after successful eradication in Japan, a country with a high prevalence of H. pylori infection.

MATERIALS AND METHODS

After successful eradication of H. pylori, 274 patients were followed up by endoscopy and urea breath test. In recurrent patients, H. pylori strains isolated initially and after recurrence were compared using PCR-based restriction fragment length polymorphism (RFLP) analysis.

RESULTS

Recurrence of H. pylori occurred in 15 of 274 patients (5.5%) at 6 months after eradication and the annual recurrence rate was 2.0% per patient year (between 1 and 6 years). PCR-based RFLP analysis of H. pylori strains isolated initially and after recurrence showed that 62.5% (at 6 months) and 100% (after 1 years) of bacteria were of different strains.

CONCLUSION

Reinfection of H. pylori was not as rare at 6 months after eradication as reported previously, and up to 6 years after eradication, the annual reinfection rate is 2.0% per patient year in Japan.

The fdxA ferredoxin gene can down-regulate frxA nitroreductase gene expression and is essential in many strains of Helicobacter pylori

Very few examples of metabolic regulation are known in the gastric pathogen Helicobacter pylori. An unanticipated case was suggested, however, upon finding two types of metronidazole (Mtz)-susceptible strains: type I, in which frxA (which encodes a nitroreductase that contributes to Mtz susceptibility) is quiescent, and type II, in which frxA is well expressed. Here we report that inactivation of the fdxA ferredoxin gene (hp277) in type I strains resulted in high-level frxA expression (in effect, making them type II). However, fdxA null derivatives were obtained from only 6 of 32 type I strains tested that were readily transformed with an frxA::aphA marker. This suggested that fdxA is often essential. This essentiality was overcome in 4 of 20 strains by inactivating frxA, which suggested both that frxA overexpression is potentially deleterious and also that fdxA has additional, often vital roles. With type II strains, in contrast, fdxA null derivatives were obtained in 20 of 23 cases tested. Thus, fdxA is dispensable in most strains that normally exhibit (and tolerate) strong frxA expression. We propose that restraint of frxA expression helps maintain balanced metabolic networks in most type I strains, that other homeostatic mechanisms predominate in type II strains, and that these complex results constitute a phenotypic manifestation of H. pylori's great genetic diversity.

Gastric lymphoma: the revolution of the past decade

BACKGROUND

Gastric MALT type lymphomas are distinct lymphomas that may develop after chronic antigenic stimulation caused by infection with Helicobacter pylori. An early antigen-dependent phase precedes the development of an antigen-independent phase.

METHODS

Narrative review.

RESULTS

The causative relationship between a chronic H. pylori infection and gastric MALT lymphomas has been based on epidemiological, histological, experimental and therapeutic studies. H. pylori eradication leads to a histological remission in +/- 70% of patients in early stage low-grade MALT lymphoma. There is no basis for therapeutic consequences in the case of persistent monoclonality. Full thickness invasion of the gastric wall and lymph node involvement and/or high-grade lymphoma denote the transition to an antigen-independent phase and calls for conventional treatment modalities. Molecular findings show a specific translocation in low-grade MALT lymphomas: t(11,18) and nuclear expression of bcl-10 that are highly indicative of the transition of the antigen-dependent into the antigen-independent phase. Other chromosomal and molecular findings are probably also involved.

CONCLUSION

The multistep pathogenesis of chronic H. pylori gastritis into low-grade gastric MALT lymphoma and tumour progression to a higher stage and grade are characterized by multiple molecular biological events. Antigen-dependency during the early phase of this malignancy is proven by the results of H. pylori eradication.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Reinfection rate in children after successful Helicobacter pylori eradication

OBJECTIVES

This study was performed to determine the rate of Helicobacter pylori reinfection after its successful eradication in children living in Germany.

DESIGN

A total of 102 children (48 boys; 31 German and 71 other nationalities; age 1.8-18 years) with a negative (13)C-urea breath test 8 weeks after triple therapy were followed up by a (13)C-urea breath test every 6 months. The cohort included 11 children aged <6 years, 58 children aged > or =6 to 12 years, and 33 children > or =12 years.

RESULTS

The mean duration (+/- standard deviation) of follow-up was 15.5 +/- 11.9 months with a maximum of 4.9 years, representing 132 patient years. Only three children (aged 9.7-14.9 years, one German, two Turkish) tested positive at 6, 12, and 18 months, respectively. The calculated reinfection rate was 2.3% per person per year.

CONCLUSION

The risk of reinfection with H. pylori is low in children living in Germany. There is no evidence that the reinfection rate depends on the age, sex, or nationality of the child. The low reinfection rate indicates that it is unnecessary to screen or treat asymptomatic family members in order to prevent reinfection.

Role of partner's infection in reinfection after Helicobacter pylori eradication

AIM

To evaluate whether the Helicobacter pylori status of the patient's spouse plays a role in reinfection after eradication success, and to assess the possibility of transmission of H. pylori among partners by using molecular methods.

METHODS

We studied prospectively 120 patients in whom H. pylori had been eradicated. Endoscopy with biopsies and a 13C-urea breath test were performed 1 month after completing therapy. The breath test was repeated in all patients at 6 and 12 months. At the 1-year follow-up visit (or before if reinfection occurred), a breath test was also performed on the patient's partner. Samples for the molecular study included gastric biopsies from patients and gastric content obtained by the string test from partners. The heterogeneity of ureC was studied by enzymatic digestion with MseI and HhaI enzymes of a polymerase chain reaction (PCR) product of 1179 bp belonging to the ureC gene, and different band patterns were generated after electrophoresis.

RESULTS

Four reinfections were diagnosed at 6 months, and four were diagnosed from 6 to 12 months (incidence 6.8% per patient-year). Seven of eight (87%) of the reinfected patients' spouses were infected, but H. pylori infection of spouses was also frequent (76%) among non-reinfected patients. In the multivariate analysis, age of the patient (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.87 to 0.99, P < 0.05), delta(13)CO(2) value after therapy (OR 2.51, 95% CI 1.14 to 5, P < 0.05), and therapy regimen (OR 6.23, 95% CI 1.25 to 31, P < 0.05) were the only variables that correlated with H. pylori recurrence. However, family variables (H. pylori status of spouse, breath test value of spouse, length of time couple had lived together, number of children living at home, household density) did not correlate with recurrences. Thus, the OR for the H. pylori status of spouse (adjusted by age, delta(13)CO(2) and therapy) was 2.93 (95% CI 0.29 to 29, P > 0.05). H. pylori recurrence occurred in seven of 92 (7.6%) patients when the spouse was infected (95% CI 3.7% to 15%), and in one of 28 (3.6%) patients when the spouse was H. pylori-negative (95% CI 0.6% to 18%) (P > 0.05; however, the power of this comparison was < 20%). Therefore, even if the spouse was infected, 92.4% of patients will remain uninfected 1 year after H. pylori eradication. Three reinfected patients (at 1 year) and their partners (also infected) agreed to have the endoscopy and string test performed, respectively. The molecular study revealed that H. pylori strains involved were different in all cases.

CONCLUSION

Recurrence of H. pylori infection seems to be relatively infrequent, even if the patient's spouse is H. pylori-positive. The molecular study demonstrated that the strains in reinfected patients and their partners are different, suggesting that the patient's partner does not act as a reservoir for H. pylori reinfection.

[Epidemiological aspects of Helicobacter pylori infection in childhood and adolescence]

The scope of the review is to study the epidemiological aspects of Helicobacter pylori infection and its importance during childhood and adolescence, focusing on incidence, prevalence, transmission and risk factors. The study's references included the following databases: LILACS (PAHO/ Bireme), MEDLINE, the US's National Library of Medicine and the thesis developed at University of São Paulo for the period 1983 to 1999. It was noted that Helicobacter pylori infection is mainly acquired during childhood, age-related prevalence, main risk factors are associated to low socioeconomic status, and its transmission mechanism remains unclear.

Helicobacter pylori infection is unlikely to be transmitted between partners: evidence from genotypic study in partners of infected patients

INTRODUCTION

We postulated that the oro-oral route of transmission between spouses could be an important route of transmission of Helicobacter pylori.

AIMS

To estimate the prevalence of different genotypes of H. pylori as distinguished by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in our local population, and to compare the genotypes of H. pylori isolated from patients and their spouses.

METHODS

Gastric biopsies were obtained from 183 dyspeptic patients during endoscopy. PCR for H. pylori was carried out using the uceC gene for amplification, and PCR products were digested further for RFLP analysis using the enzyme MboI. Spouses of H. pylori-positive index cases were screened for the infection using serological testing; if found to be positive serologically, endoscopy and gastric biopsies were performed for genotypic study of the micro-organism. For couples with indistinguishable H. pylori strain on RFLP with restriction endonuclease MboI, the process of RFLP was repeated with digestion of the PCR products using restriction endonuclease HhaI.

RESULTS

We established our PCR technique to be 89.5% sensitive and 95.5% specific. Eighty-nine subjects were found to be H. pylori positive by PCR, and eight different genotypic strains were found according to our RFLP analysis. Two genotypes accounted for 80.8% of the cases. Sixteen of 31 spouses tested serologically for H. pylori were positive. All 13 spouses who agreed to undergo endoscopy were PCR positive for H. pylori. Five couples shared indistinguishable H. pylori genotypes, but this strain was also the commonest genotype in our local population, as based on RFLP with restriction endonuclease MboI. Further RFLP on the PCR products on these five couples using restriction endonucleases HhaI showed that the H. pylori isolated from these five couples were of different strains.

CONCLUSION

The oro-oral route of transmission between spouses is unlikely to be an important mode for H. pylori infection.

Recurrence of Helicobacter pylori infection and the long-term outcome of peptic ulcer after successful eradication in Japan

Recurrence of peptic ulcer after successful eradication of Helicobacter pylori is closely associated with reinfection. The aim of this study was to examine the recurrence of peptic ulcer and reinfection with H. pylori after successful eradication. To eradicate H. pylori infection, patients with active peptic ulcer disease were assigned to two treatment groups depending on the year of their enrollment (AM group and OAMR group). Patients in the AM group received 400 mg of cimetidine twice per day, 300 mg of amoxicillin three times per day, and 250 mg of metronidazole three times per day for 2 weeks. Patients in the OAMR group received 20 mg of omeprazole once per day, 500 mg of amoxicillin granules three times per day, 250 mg of metronidazole three times per day, and 150 mg of roxithromycin twice per day for 1 week. After endoscopy verified ulcer scarring and successful eradication of H. pylori infection, study patients were followed up monthly and did not undergo acid-suppressive therapy. Endoscopy was performed at 6-month intervals for the 1st year. After the 1st year, follow-up endoscopies were performed annually. In total, 107 patients with peptic ulcer (duodenal ulcer [DU], 65; gastric ulcer [GU], 42) were followed up for a mean period of approximately 2 years. Recurrence of infection occurred in 10 (9.3%) of 107 patients (AM group, 9; OAMR group, 1) after 210 patient-years of follow-up; the recurrence rate was 4.8% per patient-year. Recurrence of H. pylori infection was significantly higher in the AM group (23.1%) than in the OAMR group (1.5%). H. pylori infection recurred in two patients 6 months after eradication therapy, in seven 1 year after, and in one 2 years after. Thereafter, no further cases of H. pylori recurrence were observed. During follow-up periods, seven cases of ulcer recurrence were observed (DU, 4; GU, 3). The rate of peptic ulcer recurrence within 2 years after eradication therapy was significantly higher than that after more than 2 years. Four cases of ulcer recurrence (DU, 3; GU, 1) also had recurrence of H. pylori infection. One recurrent case of DU without reinfection was associated with nonsteroidal anti-inflammatory drugs. The remaining two cases of GU recurred without H. pylori reinfection. In conclusion, peptic ulcer recurrence rarely occurred (3 [2.9%] of 103) in patients cured of H. pylori infection. Reinfection after apparent successful eradication was rarely noted when a powerful therapeutic regimen in eradication was used. Therefore, to eradicate H. pylori, a highly effective therapeutic regimen should always be used.

Recrudescence and reinfection with Helicobacter pylori after eradication therapy in Bangladeshi adults

BACKGROUND & AIMS

In developing countries where Helicobacter pylori infection is widespread, posttherapeutic recurrence rates may be high. Many of the limited studies available have methodological problems and show varied recurrence rates. We determined late recrudescence rates, true reinfection, and ulcer recurrence.

METHODS

One hundred five Bangladeshi patients with H. pylori infection and duodenal ulcer disease were treated with a triple therapy. Follow-up included 13C-urea breath tests, endoscopy, and biopsy-based tests. In reinfected patients, genomic typing compared pretherapeutic and posttherapeutic strains.

RESULTS

Recrudescence, associated with nitroimidazole-based treatment, occurred in 15 of 105 patients (14%) within the first 3 months, but only 8 of 105 patients tested positive 4 weeks after therapy ended. True reinfection was diagnosed in 11 of 105 patients between 3 and 18 months after therapy. The annual reinfection rate was 13%, based on a total follow-up of 84.7 patient years. Ulcer relapse occurred in 2 of 15 (13%) recrudescence cases and in 6 of 11 (55%) reinfection cases, but also in 4 of 73 (5%) H. pylori-negative patients.

CONCLUSIONS

In Bangladesh, late recrudescence of H. pylori after eradication therapy occurs within the first 3 months. The reinfection rate is high and might influence cost-benefit analyses for determining diagnostic and therapeutic procedures.

Helicobacter pylori intrafamilial infections: change in source of infection of a child from father to mother after eradication therapy

Biopsy specimens of the antrum and corpus were obtained from four Helicobacter pylori-infected members of a family and from the same boy (son 1) in whom the infection reappeared after simultaneous successful eradication treatment of three family members, excluding the mother. A total of 18 to 60 H. pylori isolates were obtained from each specimen and subjected to rRNA gene restriction pattern analysis. The father's isolates and the initial isolates from son 1 showed the same HindIII type, which was divided into three HaeIII subtypes. Isolates from the mother and a brother (son 2) and posttreatment isolates from son 1 showed a distinct HindIII type (with one minor subtype), which was divided into six HaeIII subtypes. All subtypes of the initial isolates from son 1 were present in the father's isolates, and all subtypes of the posttreatment isolates from son 1 were present in the mother's isolates but not in son 2's. Electron microscopic analysis of the biopsy specimens demonstrated extremely high levels of H. pylori colonization in the father's gastric mucosa. H. pylori adherence with a ruffle formation was also demonstrated. The findings suggest that son 1 was infected initially with the H. pylori strain of the father and son 2 was infected with the H. pylori strain of the mother and that after eradication therapy son 1 was reinfected with the H. pylori strain of the mother, who did not undergo eradication therapy.

Six-year follow-up after Helicobacter pylori eradication in peptic ulcer disease

BACKGROUND

The longterm outlook after Helicobacter pylori (H. pylori) eradication in peptic ulcer disease is unclear.

AIM

This study documents H. pylori recurrence, dyspeptic symptoms and anti-secretory therapy in peptic ulcer patients six years or more after H. pylori eradication.

METHODS

Peptic ulcer patients with H. pylori eradication between 1990 and 1992 were included. Infection recurrence was diagnosed by 13-carbon urea breath test (UBT). Dyspeptic symptoms and anti-secretory therapy use were assessed by questionnaire.

RESULTS

Sixty-one patients completed the study protocol. Mean follow-up after eradication was 6.1 years (range 4.8-8.3). Four patients had a positive UBT. H. pylori recurrence rate was 6.6% or 0.02% per patient per year. Forty-two patients (69%) had dyspeptic symptoms. Heartburn and belching were more common than pain (p<0.001). All four patients with H. pylori recurrence had symptoms compared with 38 of 57 H. pylori-negative patients (p>0.05). Ten of 61 patients (16.4%) were taking anti-secretory therapy and their dyspepsia scores were higher.

CONCLUSIONS

Despite a low H. pylori recurrence rate, longterm dyspeptic symptoms were common in peptic ulcer patients after H. pylori eradication. The symptoms are mainly reflux in type and require anti-secretory therapy in only a minority of patients.

Consequences of Helicobacter pylori cure in ulcer patients

In the complex pathogenesis of genuine ulcer disease Helicobacter pylori (H. pylori) is an essential, although not on its own sufficient, causal factor. Eradication of the infection heals the active ulcer and, in the long term, leads to a drastic reduction in ulcer recurrence and attendant complications. Some patients remain symptomatic even without ulcer recurrence, and in these, pre-existing, exacerbated or induced gastro-oesophageal reflux disease is probably of some significance. Possible causes of ulcer relapse are reinfection, the use of ulcerogenic drugs and persistent gastric hypersecretion. In adults, and probably also in children from the age of six years, H. pylori reinfection is rare, provided that a sensitive and specific test for H. pylori is carried out at the earliest 4 weeks after concluding anti-bacterial treatment. The most common cause of the reappearance of H. pylori is recrudescence - true reinfection hardly ever occurs. The healing of H. pylori-associated ulcer disease improves the patient's quality of life and possibly also life expectancy. Computer-aided calculations, together with a randomized controlled study, have shown not only that individual patients benefit, but that also the health system profits financially. The hypothetical negative effects of H. pylori eradication treatment are still being controversially discussed.

Performance criteria of DNA fingerprinting methods for typing of Helicobacter pylori isolates: experimental results and meta-analysis

Typing systems are used to discriminate between isolates of Helicobacter pylori for epidemiological and clinical purposes. Discriminatory power and typeability are important performance criteria of typing systems. Discriminatory power refers to the ability to differentiate among unrelated isolates; it is quantitatively expressed by the discriminatory index (DI). Typeability refers to the ability of the method to provide an unambiguous result for each isolate analyzed; it is quantitatively expressed by the percentage of typeable isolates. We evaluated the discriminatory power and the typeability of the most currently used DNA fingerprinting methods for the typing of H. pylori isolates: ribotyping, PCR-based restriction fragment length polymorphism (PCR-RFLP) analysis, and random amplified polymorphism DNA (RAPD) analysis. Forty epidemiologically unrelated clinical isolates were selected to constitute a test population adapted to the evaluation of these performance criteria. A meta-analysis of typeability and discriminatory power was conducted retrospectively with raw data from published studies in which ribotyping, PCR-RFLP, RAPD, repetitive extragenic palindromic DNA sequence-based PCR (REP-PCR), or pulsed-field gel electrophoresis (PFGE) was used. Experimental results and the meta-analysis demonstrated the optimal typeability (100%) and the excellent discriminatory powers of PCR-based typing methods: RAPD analysis, DIs, 0.99 to 1; REP-PCR, DI, 0.99; and PCR-RFLP analysis, DIs, 0.70 to 0.97). Chromosome restriction-based typing methods (ribotyping and PFGE) are limited by a low typeability (12.5 to 75%) that strongly decreases their discriminatory powers: ribotyping, DI, 0.92; PFGE, DIs, 0.24 to 0.88. We do not recommend the use of ribotyping and PFGE for the typing of H. pylori isolates. We recommend the use of PCR-based methods.

Quasispecies development of Helicobacter pylori observed in paired isolates obtained years apart from the same host

Helicobacter pylori isolates show greater genetic diversity than other bacterial species studied, but the basis for this phenomenon is unknown. Whether detectable genomic mutation appears within an H. pylori population during persistent colonization was investigated. Paired H. pylori populations obtained across 7- to 10-year intervals from 13 patients were characterized by use of methods including polymerase chain reaction (PCR) genotyping for cagA, vacA, iceA, recA, and IS605; random arbitrarily primed DNA (RAPD)-PCR and amplified fragment length polymorphism (AFLP) analysis; and ELISA, to determine Lewis phenotypes. Genotyping, including recA sequence analysis, revealed that initial and follow-up populations represented the same population in 11 patients (85%). Nevertheless, distinct dissimilarities were shown within each of these 11 pairs by both RAPD-PCR and AFLP analyses. During follow-up, Lewis-y levels, but not Lewis-x levels, decreased significantly. The changes detected by RAPD-PCR and AFLP indicate that genetic drift occurs within H. pylori populations over the course of years of colonization of a single host.

Evaluation of three commercial serological tests with different methodologies to assess Helicobacter pylori infection

The sera of 142 Helicobacter pylori-positive and 32 H. pylori-negative patients were assessed by a desktop test (QuickVue), an enzyme-linked immunosorbent assay (ELISA) (HM-CAP), and a solid-phase, two-step chemiluminescent enzyme immunoassay (Immulite). These tests yielded sensitivities of 97, 97, and 91% and specificities of 97, 94, and 100%, respectively. In conclusion, the desktop test and the ELISA are more sensitive than the chemiluminescent enzyme immunoassay (P < 0.05). The chemiluminescent enzyme immunoassay has the advantage that it is fully automated.

Disease management in ulcer disease

BACKGROUND

Our knowledge of Helicobacter pylori infection indicates that it is possible to eliminate ulcer disease and improve quality of life for ulcer patients. Treatment is evidence-based and cost-effective. However, though we now have the tools, we have not yet been able to eliminate ulcer disease from society. Dissemination of knowledge and treatment implementation have been problematic. In primary care, there is diagnostic and therapeutic chaos regarding this infection. Disagreement exists on indications for treatment. Expenditure on acid-reducing drugs has greatly increased. Clearly we are not treating all ulcer patients properly (undertreatment); instead we have incorporated H. pylori therapy ('test and treat') into our approach to dyspepsia (overtreatment). Anti-H. pylori therapy in patients with non-ulcer dyspepsia may increase costs because most patients still suffer from symptoms after antibiotic therapy, and therefore require further diagnostic procedures and prescription of new drugs. In order to redeem the great promise of H. pylori, we must focus less on new ulcer patients, because the incidence is rapidly decreasing in Western Europe. Prevalence of ulcer disease, however, is still high. Thus we need to focus more on prevalent cases. We ought to seek and treat those persons already known to have ulcer disease. Systematic 'case-finding' strategies must be performed using standard protocols. Only such 'disease management' programmes performed at the primary care level will suffice to eliminate ulcer disease while also being cost-effective.

HP0333, a member of the dprA family, is involved in natural transformation in Helicobacter pylori

Helicobacter pylori is naturally competent for DNA transformation, but the mechanism by which transformation occurs is not known. For Haemophilus influenzae, dprA is required for transformation by chromosomal but not plasmid DNA, and the complete genomic sequence of H. pylori 26695 revealed a dprA homolog (HP0333). Examination of genetic databases indicates that DprA homologs are present in a wide variety of bacterial species. To examine whether HP0333 has a function similar to dprA of H. influenzae, HP0333, present in each of 11 strains studied, was disrupted in two H. pylori isolates. For both mutants, the frequency of transformation by H. pylori chromosomal DNA was markedly reduced, but not eliminated, compared to their wild-type parental strains. Mutation of HP0333 also resulted in a marked decrease in transformation frequency by a shuttle plasmid (pHP1), which differs from the phenotype described in H. influenzae. Complementation of the mutant with HP0333 inserted in trans in the chromosomal ureAB locus completely restored the frequency of transformation to that of the wild-type strain. Thus, while dprA is required for high-frequency transformation, transformation also may occur independently of DprA. The presence of DprA homologs in bacteria known not to be naturally competent suggests a broad function in DNA processing.

Low rates of Helicobacter pylori reinfection in children

BACKGROUND & AIMS

Reinfection after treatment for Helicobacter pylori is uncommon in adults. It is more likely to occur in children because they acquire primary infection. The aim of this study was to determine whether children are likely to become reinfected with H. pylori and if there are any risk factors for reinfection.

METHODS

A prospective study of children who had documented evidence of successful treatment for H. pylori infection was performed. Sixty children were eligible for inclusion; results for 52 are presented. Children, parents, and siblings underwent [(13)C]urea breath tests. Details of family size and socioeconomic status were documented. Cox logistic regression analysis was used to determine the risk factors for reinfection.

RESULTS

The duration of follow-up was 103.8 patient-years (mean +/- SD, 24 +/-14.0 months). Forty-six (88.5%) of the index children remained clear of infection, and 6 (11.5%) children were reinfected. The mean age of those who became reinfected was 5.8 +/- 5.6 years compared with 12.3 +/- 3.0 years for those who remained clear of infection (P = 0.00001). Only 2 of 46 (4.3%) children older than 5 years of age were reinfected, although 80.8% had 1 infected parent and 65% of siblings were infected. Reinfection rate was 2.0% per person per year in children older than 5 years. Living with infected parents and siblings and low socioeconomic status were not risk factors for reinfection. In logistic regression analysis, age was the only risk factor for reinfection.

CONCLUSIONS

Reinfection with H. pylori occurs rarely in children older than 5 years of age regardless of socioeconomic group or number of infected family members. These findings also indicate that it is not necessary to treat all family members to achieve long-term eradication of H. pylori.