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

Viable but non-cultivable state in oral microbiota: a critical review of an underexplored microbial survival strategy

The viable but non-cultivable (VBNC) state and persister cells, two dormancy phenomena in bacteria, differ in various aspects. The entry of bacteria into the VBNC state as a survival strategy under stressful conditions has gained increasing attention in recent years, largely due to the higher tolerance of VBNC cells to antibiotics and antimicrobials resulting from their low metabolic activity. The oral cavity favors biofilm growth in dental hard tissues, resulting in tooth decay and periodontitis. Despite advances in VBNC state detection in the food industry and environment, the entry capability of oral bacteria into the VBNC state remains poorly documented. Furthermore, the VBNC state has recently been observed in oral pathogens, including Porphyromonas gingivalis, which shows potential relevance in chronic systemic infections, Enterococcus faecalis, an important taxon in endodontic infections, and Helicobacter pylori, which exhibits transient presence in the oral cavity. Further research could create opportunities to develop novel therapeutic strategies to control oral pathogens. The inability of conventional culture-based methods to identify VBNC bacteria and the metabolic reactivation of dormant cells to restore susceptibility to therapies highlights a notable gap in anti-VBNC state strategies. The lack of targeted approaches tested for efficacy against VBNC bacteria underscores the need to develop novel detection methods. This review discusses the VBNC state, its importance in public health, and diagnostic techniques, with a special focus on the VBNC state in oral bacteria.

Screening and surveillance for gastric cancer: Does family history play an important role in shaping our strategy?

Family history is an important risk factor of gastric cancer. No guidelines have been developed that target gastric cancer with a family history; only hereditary familial gastric cancer is targeted. We review the available evidence regarding the familial aggregation mechanisms of gastric cancer and a strategy of screening and surveillance for gastric cancer in individuals with a positive family history of the disease. As there is a synergic effect of Helicobacter pylori infection and family history on the increased risk of gastric cancer, Helicobacter pylori eradication should be considered in all infected individuals with a family history of gastric cancer. Currently, there is weak evidence indicating that suitable timing to initiate eradication therapy is at the age of 20, when precancerous lesions, including significant gastric atrophy and intestinal metaplasia, have not been established. Reasonable timing to initiate screening for gastric cancer in individuals with a family history of gastric cancer is 10 years prior to the age of onset of gastric cancer in affected relatives. A 2-year surveillance interval, instead of the 3-year interval recommended in the present guidelines, may be better to detect early gastric cancer in those individuals who have already developed precancerous gastric lesions.

Probiotics as the live microscopic fighters against Helicobacter pylori gastric infections

BACKGROUND

Helicobacter pylori (H. pylori) is the causative agent of stomach diseases such as duodenal ulcer and gastric cancer, in this regard incomplete eradication of this bacterium has become to a serious concern. Probiotics are a group of the beneficial bacteria which increase the cure rate of H. pylori infections through various mechanisms such as competitive inhibition, co-aggregation ability, enhancing mucus production, production of bacteriocins, and modulating immune response.

RESULT

In this study, according to the received articles, the anti-H. pylori activities of probiotics were reviewed. Based on studies, administration of standard antibiotic therapy combined with probiotics plays an important role in the effective treatment of H. pylori infection. According to the literature, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus GG, and Saccharomyces boulardii can effectively eradicate H. pylori infection. Our results showed that in addition to decrease gastrointestinal symptoms, probiotics can reduce the side effects of antibiotics (especially diarrhea) by altering the intestinal microbiome.

CONCLUSION

Nevertheless, antagonist activities of probiotics are H. pylori strain-specific. In general, these bacteria can be used for therapeutic purposes such as adjuvant therapy, drug-delivery system, as well as enhancing immune system against H. pylori infection.

Three-Decade Failure to the Eradication of Refractory Helicobacter pylori Infection and Recent Efforts to Eradicate the Infection

BACKGROUND

Helicobacter pylori causes dangerous and deadly diseases such as gastric cancer and duodenal ulcers. Eradication and treatment of this bacterium are very important due to the deadly diseases caused by H. pylori and the high cost of treatment for countries.

METHODS

Thus, we present a complete list of the most important causes of failure in the treatment and eradication of H. pylori, and address new therapeutic methods that may be effective in controlling this bacterium in the future.

RESULTS

Many efforts have been made to control and eradicate this bacterium over the years, but no success has been achieved since its eradication is a complex process affected by the bacterial properties and host factors. Previous studies have shown that various factors are involved in the failure to eradicate H. pylori, such as new genotypes of the bacterium with higher pathogenicity, inappropriate patient cooperation, mutations, biofilm formation and dormant forms that cause antibiotic resistance, acidic stomach pH, high bacterial load, smoking, immunosuppressive features and intracellular occurrence of H. pylori. On the other hand, recent studies reported that the use of probiotics, nanoparticles, antimicrobial peptides, natural product and vaccines can be helpful in the treatment and eradication of H. pylori infections.

CONCLUSION

Eradication of H. pylori is crucial for the treatment of important diseases such as gastric cancer. Therefore, it seems that identifying the failure causes of treating this bacterium can be helpful in controlling the infections. Besides, further studies on new therapeutic strategies may help eradicate H. pylori in the future.

Screening and eradication of Helicobacter pylori for gastric cancer prevention: the Taipei global consensus

OBJECTIVE

A global consensus meeting was held to review current evidence and knowledge gaps and propose collaborative studies on population-wide screening and eradication of Helicobacter pylori for prevention of gastric cancer (GC).

METHODS

28 experts from 11 countries reviewed the evidence and modified the statements using the Delphi method, with consensus level predefined as ≥80% of agreement on each statement. The Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach was followed.

RESULTS

Consensus was reached in 26 statements. At an individual level, eradication of H. pylori reduces the risk of GC in asymptomatic subjects and is recommended unless there are competing considerations. In cohorts of vulnerable subjects (eg, first-degree relatives of patients with GC), a screen-and-treat strategy is also beneficial. H. pylori eradication in patients with early GC after curative endoscopic resection reduces the risk of metachronous cancer and calls for a re-examination on the hypothesis of 'the point of no return'. At the general population level, the strategy of screen-and-treat for H. pylori infection is most cost-effective in young adults in regions with a high incidence of GC and is recommended preferably before the development of atrophic gastritis and intestinal metaplasia. However, such a strategy may still be effective in people aged over 50, and may be integrated or included into national healthcare priorities, such as colorectal cancer screening programmes, to optimise the resources. Reliable locally effective regimens based on the principles of antibiotic stewardship are recommended. Subjects at higher risk of GC, such as those with advanced gastric atrophy or intestinal metaplasia, should receive surveillance endoscopy after eradication of H. pylori.

CONCLUSION

Evidence supports the proposal that eradication therapy should be offered to all individuals infected with H. pylori. Vulnerable subjects should be tested, and treated if the test is positive. Mass screening and eradication of H. pylori should be considered in populations at higher risk of GC.

Risk factors for recurrence of Helicobacter pylori infection after successful eradication in Chinese children: A prospective, nested case-control study

BACKGROUND

Limited research has been published on the recurrence of Helicobacter pylori infection and risk factors in Chinese children. Our study aimed to identify risk factors for Helicobacter pylori infection recurrence after successful eradication in children.

MATERIALS AND METHODS

A prospective, nested case-control study was performed. A cohort of 230 children with successful eradication of Helicobacter pylori in Baoding (China) was selected from January 2018 to February 2019. A standardized questionnaire was used to obtain socioeconomic details. Eradication regimens and Helicobacter pylori antibiotic susceptibility testing results were also recorded. Interleukin-1β level, interferon-γ level, and genetic susceptibility (IFNGR1 and PTPRZ1 gene polymorphisms) were analyzed. All children were followed for 1 year.

RESULTS

Among 218 (94.8%) children who were successfully followed, 41 children (18.8%) had a Helicobacter pylori infection recurrence. The recurrence rate was higher in children ≤10 years old than >10 years old (22.8% vs 7.1%, P = .01). There was no significant difference between the recurrence group and the non-recurrence group in terms of types of therapy and antibiotic sensitivity (P > .05). Multivariable regression results indicated that residence in urban areas, higher household income, and having lunch at home were significantly protective against recurrence (OR 0.155, 0.408, and 0.351 respectively), whereas Helicobacter pylori infection in family members increased the risk of recurrence (OR 2.283). The levels of IL-1β and IFN-γ exhibited no significant difference between the recurrence group and the non-recurrence group. The allele frequency of G in the IFNGR1-56 site, A in the IFNGR1-600 site, and T in the IFNGR1-565 site was significantly higher in the recurrence group when compared to the non-recurrence group (P < .05).

CONCLUSIONS

The Helicobacter pylori infection recurrence rate is high in children in Baoding region and is closely correlated to socioeconomic factors. The IFNGR1 gene polymorphism may be an independent risk factor for Helicobacter pylori infection recurrence.

Eradication rate of Helicobacter pylori reinfection in Korea: A retrospective study

BACKGROUND AND AIM

Guidelines for selecting the eradication regimen for Helicobacter pylori reinfection remain unclear. This study aimed to evaluate the eradication rate of H. pylori reinfection in patients with a previous infection successfully eradicated with index triple therapy.

METHODS

This was a single-center, retrospective case-control study. A total of 10 468 H. pylori-infected patients treated with proton-pump inhibitor-based triple eradication therapy at a tertiary medical institution between 2005 and 2016 were enrolled. We reviewed the medical records of the enrolled patients and compared the treatment outcomes in those with H. pylori reinfection after a successful eradication.

RESULTS

Helicobacter pylori infection was successfully eradicated with the index triple therapy in 7770 patients (74.2%). Among 3567 patients followed up for > 1 year, H. pylori reinfection occurred in 420 (11.8%; 3.06% per person-year) during a median follow-up of 39.1 months (interquartile range, 23.5-58.7 months). Of these patients, 164 received eradication therapy for reinfection (triple therapy in 102 and quadruple therapy in 62) and had follow-up data. Triple therapy showed an eradication rate of 78.4% for H. pylori reinfection, which was not significantly different from that of the index triple therapy (P = 0.394). Quadruple therapy for reinfection exhibited a better eradication rate (87.1%) than triple therapy but without statistical significance (P = 0.237).

CONCLUSIONS

Retreatment with triple therapy for H. pylori reinfection after successful eradication of prior infection showed comparable outcomes to the index triple therapy. Bismuth-containing quadruple therapy for reinfection tended to have a better eradication rate than did triple therapy.

Recurrence of Helicobacter pylori infection: incidence and influential factors

Background:

Helicobacter pylori (H. pylori) eradication has been widely used. The recurrence rate of H. pylori after eradication and its related factors are gaining more and more attention. Our study aimed to determine the recurrence rate of H. pylori infection after successful eradication, and analyze its influential factors.

Methods:

We prospectively studied 1050 patients with upper gastrointestinal symptoms who were diagnosed as H. pylori infection by gastroscopy and underwent eradication therapies from April 2013 to January 2014. The ¹³C-urea breath test (UBT) or Warthin-Starry (WS) staining was done at 8 to 12 weeks after the therapy. Patients with successful eradication were followed by repeated UBT or gastroscopy at one year and 3 years after therapy, as well as, questionnaire surveys. Recurrence was considered if the UBTs or WS staining of biopsy were positive. One-year and 3-year recurrence rates were calculated, and analyzed the differences between recurred patients and others in basic data, sociological characteristics, lifestyle.

Results:

A total of 743 patients finished the 1-year follow-up, and the 1-year recurrence rate was 1.75%. Of the 607 patients who finished the 3-year follow-up, 28 patients recurred, and the 3-year recurrence rate was 4.61%. Analysis of variance showed that low-income, poor hygiene condition of dining out place, and receiving invasive diagnoses or treatments were significant risk factors for H. pylori infection recurrence. Logistic regression analysis demonstrated that the combination of invasive diagnoses or treatments, the level of income, and the hygiene standard of dining out place were significant and independent influential factors of the recurrence of H. pylori.

Conclusions:

The 1-year and 3-year recurrence rates of H. pylori infection after eradication therapy are 1.75% and 4.61%. Low-income, poor hygiene condition of dining out place, and a combination of invasive diagnoses or treatments are independent risk factors of H. pylori recurrence.

Helicobacter pylori management in ASEAN: The Bangkok consensus report

Helicobacter pylori (H. pylori) infection remains to be the major cause of important upper gastrointestinal diseases such as chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. H. pylori management in ASEAN: the Bangkok consensus report gathered key opinion leaders for the region to review and evaluate clinical aspects of H. pylori infection and to develop consensus statements, rationales, and grades of recommendation for the management of H. pylori infection in clinical practice in ASEAN countries. This ASEAN Consensus consisted of 34 international experts from 10 ASEAN countries, Japan, Taiwan, and the United States. The meeting mainly focused on four issues: (i) epidemiology and disease association; (ii) diagnostic tests; (iii) management; and (iv) follow-up after eradication. The final results of each workshop were presented for consensus voting by all participants. Statements, rationale, and recommendations were developed from the available current evidence to help clinicians in the diagnosis and treatment of H. pylori and its clinical diseases.

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.

Diagnosis of Helicobacter pylori recurrence: relapse or reinfection? Usefulness of molecular tools

BACKGROUND AND AIMS

Infection due to Helicobacter pylori causes many gastrointestinal diseases including peptic ulcers and gastric carcinoma. Their treatment and prevention depends on the successful eradication of H. pylori. However, even after a well-conducted treatment, H. pylori persists in about 10-30% of patients. Recurrent infections can correspond to relapse or to re-infection and require appropriate medical care. In this study, we explore retrospectively three clinical cases using molecular methods, and propose new guidelines for the diagnosis of recurrence.

MATERIAL AND METHODS

Ten colonies of H. pylori were selected from the primary culture of biopsy samples taken from the antrum and fundus for each patient. The genotype of each isolated colony was determined by analyzing the polymorphism of two housekeeping genes, hspA and glmM. The genome-wide composition of H. pylori strains was studied using in house macro-arrays designed.

RESULTS

Relapses were demonstrated by the stability of genotypes and the slight genetic variability of strains on macro-arrays. Two patients suffered from relapses, one and three years after H. pylori treatment. For the third patient, both the polymorphism of glmM and hspA genotypes and the diversity of CDSs identified on macro-arrays suggested that several episodes of re-infection occurred, 1-8 years after eradication.

CONCLUSION

For the three clinical cases, molecular methods allowed identifying the causes of recurrent infections. We suggest to study genotype to distinguish between relapse and re-infection in order to adapt the treatment and the follow-up of patients to the nature of recurrence.

Systematic review and meta-analysis: triple therapy combining a proton-pump inhibitor, amoxicillin and metronidazole for Helicobacter pylori first-line treatment

BACKGROUND

Due to clarithromycin resistance, the current efficacy of Helicobacter pylori first-line triple therapies including clarithromycin is low. It seems reasonable to explore alternative clarithromycin-free therapies.

OBJECTIVES

The objective of this study was to evaluate the efficacy of triple therapy including a proton-pump inhibitor (PPI), amoxicillin and metronidazole (PAM) as first-line H. pylori therapy by systematic review and meta-analysis.

METHODS

Studies evaluating PAM in adult patients were included. Meta-analyses comparing PAM with other treatments were performed. The primary endpoint was the ITT eradication rate for H. pylori first-line treatment. In addition, sensitivity analyses ascertained the effects of treatment schedule, dosage and duration on cure rates.

RESULTS

Ninety-four studies (8061 patients) were included. Meta-analyses comparing PAM versus clarithromycin-including triple therapies showed a significant difference in favour of PPI, amoxicillin and clarithromycin (PAC) (70% versus 77.1%; OR = 0.70, 95% CI = 0.56-0.88) and PPI, metronidazole and clarithromycin (PMC) therapy (66.4% versus 77.7%; OR = 0.55, 95% CI = 0.39-0.76). Sensitivity analyses showed a similar efficacy of PAM versus PAC when drugs were administered for 14 days (80% versus 84%; OR = 0.70, 95% CI = 0.44-1.12). There were not enough studies to perform further comparisons. Number of antibiotic doses (P = 0.012), length of treatment (P < 0.001) and use of high metronidazole doses (P = 0.021) were related to higher cure rates in the sensitivity analysis including observational studies.

CONCLUSIONS

PAM was less efficacious than clarithromycin-including triple therapies. However, its efficacy was similar to that of PAC when drugs were administered for 14 days, although ITT cure rates did not reach 90%. Use of 14 day, thrice daily and high-metronidazole-dose PAM treatments markedly increased the cure rate.

Gastric Cancer: How Can We Reduce the Incidence of this Disease?

Gastric cancer remains a prevalent disease worldwide with a poor prognosis. Helicobacter pylori plays a major role in gastric carcinogenesis. H. pylori colonization leads to chronic gastritis, which predisposes to atrophic gastritis, intestinal metaplasia, dysplasia, and eventually gastric cancer. Screening, treatment, and prevention of H. pylori colonization can reduce the incidence of gastric cancer. Other interventions that may yield a similar effect, although of smaller magnitude, include promotion of a healthy lifestyle including dietary measures, non-smoking, low alcohol intake, and sufficient physical activity. This chapter reviews interventions that can lead to a decline in gastric cancer incidence in high and low incidence countries.

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.

Defining the Roles of IFN-γ and IL-17A in Inflammation and Protection against Helicobacter pylori Infection

CD4⁺ T cells have been shown to be essential for vaccine-induced protection against Helicobacter pylori infection. However, the effector mechanisms leading to reductions in the gastric bacterial loads of vaccinated mice remain unclear. We have investigated the function of IFN-γ and IL-17A for vaccine-induced protection and inflammation (gastritis) using IFN-γ-gene-knockout (IFN-γ^-/-) mice, after sublingual or intragastric immunization with H. pylori lysate antigens and cholera toxin. Bacteria were enumerated in the stomachs of mice and related to the gastritis score and cellular immune responses. We report that sublingually and intragastrically immunized IFN-γ^-/- mice had significantly reduced bacterial loads similar to immunized wild-type mice compared to respective unimmunized infection controls. The reduction in bacterial loads in sublingually and intragastrically immunized IFN-γ^-/- mice was associated with significantly higher levels of IL-17A in stomach extracts and lower gastritis scores compared with immunized wild-type mice. To study the role of IL-17A for vaccine-induced protection in sublingually immunized IFN-γ^-/- mice, IL-17A was neutralized in vivo at the time of infection. Remarkably, the neutralization of IL-17A in sublingually immunized IFN-γ^-/- mice completely abolished protection against H. pylori infection and the mild gastritis. In summary, our results suggest that IFN-γ responses in the stomach of sublingually immunized mice promote vaccine-induced gastritis, after infection with H. pylori but that IL-17A primarily functions to reduce the bacterial load.

Reinfection after successful eradication of Helicobacter pylori in three different populations in Alaska

We performed a study to determine rates of reinfection in three groups followed for 2 years after successful treatment: American Indian/Alaska Native (AI/AN) persons living in urban (group 1) and rural (group 2) communities, and urban Alaska non-Native persons (group 3). We enrolled adults diagnosed with H. pylori infection based on a positive urea breath test (13C-UBT). After successful treatment was documented at 2 months, we tested each patient by 13C-UBT at 4, 6, 12 and 24 months. At each visit, participants were asked about medication use, illnesses and risk factors for reinfection. We followed 229 persons for 2 years or until they became reinfected. H. pylori reinfection occurred in 36 persons; cumulative reinfection rates were 14·5%, 22·1%, and 12·0% for groups 1, 2, and 3, respectively. Study participants who became reinfected were more likely to have peptic ulcer disease (P = 0·02), low education level (P = 0·04), or have a higher proportion of household members infected with H. pylori compared to participants who did not become reinfected (P = 0·03). Among all three groups, reinfection occurred at rates higher than those reported for other US populations (<5% at 2 years); rural AI/AN individuals appear to be at highest risk for reinfection.

Helicobacter pylori is not eradicated after triple therapy: a nested PCR based study

Detection of Helicobacter pylori after triple therapy is usually carried out by either rapid urease test (RUT), urea breath test (UBT), histology, bacterial isolation, and single round PCR or serological tests. In this study, antral biopsy specimens from 25 patients were tested for H. pylori by RUT, culture, histology, and nested PCR in their antral biopsy specimens before and after treatment. Three genes, namely, heat shock protein (hsp60), phosphoglucosamine mutase (ureC), and flagellar export ATP synthase (fliI) of H. pylori were targeted. Of the 25 antral biopsy specimens, the RUT, culture, histology, and nested PCR positivity dropped from 81.8% to 12%, 31% to 0%, 100 to 84%, and 100% to 92%, respectively, before and after therapy. Further, hsp60 specific amplicons from 23 out of 25 patients gave identical restriction pattern, while 6 fliI and 1 ureC specific amplicon produced different restriction pattern. Furthermore, variations in fliI gene sequences in H. pylori after treatment were also confirmed by sequencing and compared in silico. Nested PCR based detection of H. pylori is more sensitive method to detect H. pylori after therapy than culture, RUT, and histology. Further, this study suggests that H. pylori is not eradicated completely after triple therapy.

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.

Long-term follow up Helicobacter Pylori reinfection rate after second-line treatment: bismuth-containing quadruple therapy versus moxifloxacin-based triple therapy

BACKGROUND

The increasing trend of antibiotic resistance requires effective second-line Helicobacter pylori (H. pylori) treatment in high prevalence area of H. pylori. The aim of our study was to evaluate the reinfection rate of H. pylori after second-line treatment that would determine the long-term follow up effect of the rescue therapy.

METHODS

A total of 648 patients who had failed previous H. pylori eradication on standard triple therapy were randomized into two regimens: 1, esomeprazole (20 mg b.i.d), tripotassium dicitrate bismuthate (300 mg q.i.d), metronidazole (500 mg t.i.d), and tetracycline (500 mg q.i.d) (EBMT) or 2, moxifloxacin (400 mg q.d.), esomeprazole (20 mg b.i.d), and amoxicillin (1000 mg b.i.d.) (MEA). At four weeks after completion of eradication therapy, H. pylori tests were performed with 13C urea breath test or invasive tests. In patients who maintained continuous H. pylori negativity for the first year after eradication therapy, H. pylori status was assessed every year. For the evaluation of risk factors of reinfection, gender, age, clinical diagnosis, histological atrophic gastritis or intestinal metaplasia were analyzed.

RESULTS

The recrudescence rate of the EBMT was 1.7% and of the MEA group 3.3% (p = 0.67). The annual reinfection rate of H. pylori of EBMT was found to be 4.45% and the MEA group 6.46%. Univariate analysis (Log-rank test) showed no association with any clinical risk factor for reinfection.

CONCLUSIONS

The long-term reinfection rate of H. pylori stayed low in both of bismuth-containing quadruple therapy and moxifloxacin-based triple therapy; thus reinfection cannot affect the choice of second-line treatment.

TRIAL REGISTRATION

Clinical Trial Registration Number NCT01792700.

Seroconversion rates of Helicobacter pylori infection in Korean adults

BACKGROUND

Studies on seroconversion and its reversion rate in Korean adults with Helicobacter pylori infection are very rare. The purpose of this study was to evaluate the overall seroprevalence, seroconversion rate, and seroreversion rate of H. pylori infection in an adult population.

MATERIALS AND METHODS

We performed this retrospective cohort study on healthy adults who had visited our health screening center at Asan Medical Center more than twice between January 2000 and December 2010. We reviewed the anti- H. pylori Ab IgG profiles of the enrolled people and their family members and the results of esophagogastroduodenoscopies and a self-reported questionnaire.

RESULTS

A total of 67,212 people were enrolled in this study. The mean follow-up duration was 4.6 years, and each participant visited the center for a mean of 3.8 visits. The overall proportions of participants demonstrating persistent seropositivity, persistent seronegativity, seroconversion, and seroreversion were 53.1%, 32.5%, 4.3%, and 10.1%, respectively. The annual seroconversion rate was 2.79%. The annual crude and spontaneous seroreversion rates of the entire study population were 3.64% and 2.42%, respectively. According to multivariate logistic regression, old age (HR = 1.015), smoking (HR = 1.216), alcohol consumption more than four times per week (HR = 1.263), marriage (HR = 2.735), and living with H. pylori-infected family members (HR = 1.525) were identified as statistically significant risk factors associated with seroconversion.

CONCLUSION

The annual seroconversion rate was 2.79% in our study population. Marriage and living with H. pylori-infected family members were important risk factors affecting seroconversion in our adult population.

Long-term follow-up Helicobacter pylori reinfection rate and its associated factors in Korea

BACKGROUND

The reinfection rate of Helicobacter pylori has been reported to be low in developed countries but high in developing countries. The aim of this study is to evaluate the long-term reinfection rate of H. pylori and to investigate its associated risk factors in South Korea.

METHODS

During 2003-2010, H. pylori-positive 970 patients received standard proton pump inhibitor (PPI)-based triple eradication therapy, and follow-up H. pylori tests were performed with (13) C urea breath test or invasive tests (Giemsa histology, CLO test, and culture) 4 weeks after completion of treatment. A total of 331 patients who were maintained an H. pylori-eradicated state at 1 year after eradication were divided into two groups according to reinfection. For the evaluation of risk factors of reinfection, gender, age, smoking, alcohol, income, education, gastrointestinal symptoms, clinical diagnosis, histologic atrophic gastritis or intestinal metaplasia, and clarithromycin resistance were analyzed.

RESULTS

The follow-up period was 18-95 months (mean: 37.1 months), and H. pylori reappeared in 36 of 331 patients (10.9%), resulting in the annual reinfection rate of 3.51% per year. Multivariate analysis showed that male gender (HR 2.28; 95% CI, 1.05-5.00, p = .037) and low monthly family income (≤5000$ vs >5000$) (HR 3.54; 95% CI, 1.08-11.67, p = .038) were associated with H. pylori reinfection.

CONCLUSION

This long-term reinfection rate of H. pylori stayed rather low (3.51% per year), and male and low income determined the reinfection, factors already known to be important for H. pylori infection.

Low rate of recurrence of Helicobacter pylori infection in spite of high clarithromycin resistance in Pakistan

BACKGROUND

The aim was to investigate the reinfection rate of H. pylori during a follow-up period of 12 months in adults who had undergone eradication therapy.

METHODS

One hundred-twenty patients; 116 with gastritis, 3 with duodenal ulcer and 1 gastric ulcer, were studied. Their mean age was 41±13 years (range 18-77) and male: female ratio of 2:1. H. pylori were cultured and antibiotic sensitivity was determined by Epsilometer test (E-test) for clarithromycin (CLR) and amoxicillin (AMX). Primers of urease C gene of H. pylori and Sau-3 and Hha I restriction enzymes were used for polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). 14C urea breath test (14C-UBT) was performed 4 weeks after the eradication therapy. The successfully treated patients were observed for 12 months with 14C-UBT to assess H. pylori status. If 14C-UBT was negative, it was repeated after every 12 weeks. If 14C-UBT was positive, endoscopy was repeated with biopsies.

RESULT

The eradication therapy was successful in 102(85%) patients. Out of forty-seven H. pylori isolates cultured, clarithromycin sensitivity was present in 30(64%) and amoxicillin in 45(98%), respectively. Follow-up 14C-urea breath tests of all 102 patients who eradicated H. pylori remained negative up to 9 months. However, in 6 patients, the 14C-UBT confirmed recurrence at 12 months. The recurrence rate was 6%.

CONCLUSION

A low rate of recurrence of H. pylori infection was found in patients with dyspeptic symptoms. H. pylori isolates demonstrated a high invitro clarithromycin resistance.

Helicobacter pylori persistence in children: distinguishing inadequate treatment, resistant organisms, and reinfection

Helicobacter pylori is a worldwide infection that causes chronic gastritis, duodenal ulcers, and malignancy. Transmission of Helicobacter pylori within a family appears to be the predominant mode of contamination. Recurrence of the infection is frequently seen following treatment. Lack of eradication due to either inadequate treatment or resistant bacteria vs. reinfection have been explanations for detection of H. pylori following treatment. In this article we will discuss the concepts of inadequate treatment vs. resistant infection and reinfection as causes of persistent H. pylori infection.

Optimal therapy for Helicobacter pylori infections

Although Helicobacter pylori infection is both a common and a serious bacterial infection, antimicrobial therapies have rarely been optimized, are prescribed empirically, and provide inferior results compared with antimicrobial therapies for other common infectious diseases. The effectiveness of many of the frequently recommended H. pylori infection treatment regimens has been increasingly compromised by antimicrobial resistance. Regional data on the susceptibility of strains of H. pylori to available antimicrobials are sorely needed. Noninvasive molecular methods are possible to assess clarithromycin susceptibility in isolates obtained from stool specimens. As a general rule, clinicians should prescribe therapeutic regimens that have a ≥90% or, preferably, ≥95% eradication rate locally. If no available regimen can achieve a ≥90% eradication rate, clinicians should use the most effective regimen(s) available locally. Eradication of infection should always be confirmed after treatment in order to provide feedback regarding local effectiveness and an early warning of increasing resistance. In most regions of the world, four-drug treatment regimens, including a PPI plus three antimicrobials (clarithromycin, metronidazole/tinidazole and amoxicillin), or a PPI plus a bismuth plus tetracycline and metronidazole provide the best results. Standard triple therapy (a PPI, amoxicillin and clarithromycin) should now be avoided owing to increasing resistance to this treatment.

The effectiveness of systemic eradication therapy against oral Helicobacter pylori

BACKGROUND

Helicobacter pylori infection is associated with numerous gastroduodenal diseases. The oral cavity could be a potential extragastric reservoir for H. pylori, and oral H. pylori might cause gastric reinfection after the eradication therapy. The aim of the study was to evaluate the presence of H. pylori in oral cavity of patients with gastric H. pylori infection and to examine the effectiveness of the eradication therapy against H. pylori in stomach and in the oral cavity.

METHODS

Fifty-six patients with chronic periodontitis and gastric H. pylori were enrolled in the study. Gastric H. pylori infection was determined using (13) C-urea breath test before and 3 months after eradication therapy. The presence of the oral H. pylori was assessed using polymerase chain reaction before and 3 months after eradication therapy. The 1-week eradication therapy consisted of amoxycilin 1 g, clarithromycin 500 mg, and proton pump inhibitor 20 mg twice a day.

RESULTS

Of 56 subjects with gastric infection, 23 (41.1%) harbored H. pylori in the oral cavity. Eradication rate in stomach was 78.3%, whereas in the oral cavity, H. pylori was not detected from any sample after the eradication therapy.

CONCLUSION

Almost half of the patients with gastric H. pylori harbored the bacterium in the oral cavity. After the eradication therapy, H. pylori was not detected in the oral cavity, what suggests high effectiveness of the therapy protocol in the oral cavity, or it is possible that oral H. pylori is of a transient character.

Helicobacter pylori reinfection in Brazilian patients with peptic ulcer disease: a 5-year follow-up

BACKGROUND

The Helicobacter pylori reinfection seems to be higher in developing countries, than in developed ones. The aim of the study was to determine the annual recurrence rate of H. pylori, in Brazilian patients with peptic ulcer disease, in a 5-year follow-up.

METHODS

Patients, with peptic ulcer disease diagnosed by upper digestive endoscopy (UDE) and H. pylori infection verified by histological analysis, rapid urease test, polymerase chain reaction, and urea breath test (UBT), were treated for bacterial eradication. The cure of the infection was verified using the same tests, 3 months after. Clinical evaluation and UBT were performed after sixth and ninth month. After 1 year of follow-up, UBT and UDE were repeated. Up to the fifth year, patients were assessed twice a year and an UBT was performed annually. The patients included and all the reinfected were tested for 15 different genes of the H. pylori.

RESULTS

One hundred and forty-seven patients were followed: 19 for 1 year, eight for 2 years, four for 3 years, five for 4 years, and 98 for 5 years, totaling 557 patients/years. Recurrence did not occur in the first year. In the second year, two patients were reinfected; in the third, four patients; in the fourth, three patients; and in the fifth, one patient. The total of reinfected patients was 10. The annual reinfection rate was 1.8%.

CONCLUSION

Brazil presents a low prevalence of H. pylori reinfection, similar to the developed countries.

Reinfection rate and endoscopic changes after successful eradication of Helicobacter pylori

AIM: To determine the long-term outcomes regarding reinfection with Helicobacter pylori (H. pylori) and endoscopic changes after successful H. pylori eradication.

METHODS: From June 1994 to January 2007, 186 patients (M:F = 98:88; mean age 50.0 ± 11.4 years), in whom H. pylori had been successfully eradicated, were enrolled. The mean duration of follow up was 41.2 ± 24.0 mo.

RESULTS: H. pylori reinfection occurred in 58 patients (31.2%). The average annual reinfection rate was 9.1% per patient year. No recurrence of peptic ulcer was detected at the follow up endoscopy. There were no significant differences between the H. pylori eradication regimens for the reinfection rate and no significant differences in endoscopic findings between the H. pylori-recurred group and the H. pylori-cured group.

CONCLUSION: The reinfection rate in Korea is 9.1% which represents a decreasing trend. There was no relationship between H. pylori infection status and changes in endoscopic findings. There was also no recurrence or aggravation of ulcers.

Gastroenterology in developing countries: issues and advances

Developing countries shoulder a considerable burden of gastroenterological disease. Infectious diseases in particular cause enormous morbidity and mortality. Diseases which afflict both western and developing countries are often seen in more florid forms in poorer countries. Innovative techniques continuously improve and update gastroenterological practice. However, advances in diagnosis and treatment which are commonplace in the West, have yet to reach many developing countries. Clinical guidelines, based on these advances and collated in resource-rich environments, lose their relevance outside these settings. In this two-part review, we first highlight the global burden of gastroenterological disease in three major areas: diarrhoeal diseases, hepatitis B, and Helicobacter pylori. Recent progress in their management is explored, with consideration of future solutions. The second part of the review focuses on the delivery of clinical services in developing countries. Inadequate numbers of healthcare workers hamper efforts to combat gastroenterological disease. Reasons for this shortage are examined, along with possibilities for increased specialist training. Endoscopy services, the mainstay of gastroenterology in the West, are in their infancy in many developing countries. The challenges faced by those setting up a service are illustrated by the example of a Nigerian endoscopy unit. Finally, we highlight the limited scope of many clinical guidelines produced in western countries. Guidelines which take account of resource limitations in the form of "cascades" are advocated in order to make these guidelines truly global. Recognition of the different working conditions facing practitioners worldwide is an important step towards narrowing the gap between gastroenterology in rich and poor countries.

Fluorescence in situ hybridization confirms clearance of visible Helicobacter spp. associated with gastritis in dogs and cats

BACKGROUND

The results of studies examining the role of Helicobacter spp. in the pathogenesis of canine and feline gastritis are inconclusive. Furthermore, data evaluating the effectiveness of medical therapy for eradication of Helicobacter infection are limited.

AIM

To detect Helicobacter spp. in mucosal biopsies of dogs and cats diagnosed with gastritis, with fluorescence in situ hybridization (FISH).

ANIMALS

Three dogs and 2 cats with signs of chronic gastrointestinal disease.

METHODS

Dogs and cats infected with Helicobacter spp. were treated with triple antimicrobial therapy and fed an elimination diet for 21 days. Helicobacter spp. status in endoscopic (3 dogs, 1 cat) or surgical biopsies (1 cat) of gastric mucosa was compared pre- and posttreatment in each animal by histology, FISH analysis, and polymerase chain reaction (PCR).

RESULTS

Gastritis of varying severity with intraglandular spiral bacteria was observed in all animals. Pretreatment diagnostic tests confirmed the presence of mucosal Helicobacter spp. in all animals by FISH and histopathology and in 4/5 animals by PCR. Rapid resolution of vomiting episodes was observed in all animals. Gastric biopsies performed after triple therapy revealed clearance of visible Helicobacter spp. by histopathology and negative FISH analysis, as well as PCR in all animals.

CONCLUSIONS AND CLINICAL IMPORTANCE

Application of FISH to routine biopsy specimens enabled rapid and specific identification of Helicobacter spp. within the gastric mucosa of dogs and cats. Although medical therapy was useful in resolution of clinical signs and clearance of visible Helicobacter spp. in gastric biopsies, gastric inflammation persisted.

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.

Epidemiology of Helicobacter pylori infection

This review summarizes studies on the epidemiology of Helicobacter pylori published in peer-reviewed journals between April 2007 and March 2008. Infection with H. pylori often occurs in childhood, and once established, can persist lifelong if untreated. Prevalence of H. pylori infection is higher in developing countries when compared to developed countries, and can vary by ethnicity, place of birth, and socioeconomic factors even among persons living in the same country. Prevalence of infection is decreasing in many countries due to improvements in sanitation and living standards and the relatively recent movement of populations from rural to urban settings; however, post-treatment recurrence rates of H. pylori infection remain high in developing countries, and in given populations within developed countries. In addition, a number of recent studies have begun to explore the possible link between childhood infection with H. pylori and protection against asthma and allergy.

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.

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.

Asia-Pacific consensus guidelines on gastric cancer prevention

BACKGROUND AND AIM

Gastric cancer is a major health burden in the Asia-Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer.

METHODS

A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded.

RESULTS

Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host-bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines.

CONCLUSION

A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.

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.

Cost-effectiveness analysis between primary and secondary preventive strategies for gastric cancer

OBJECTIVE

The present study is done to assess the relative cost-effectiveness, optimal initial age, and interscreening interval between primary and secondary prevention strategies for gastric cancer.

METHODS

Base-case estimates, including variables of natural history, efficacy of intervention, and relevant cost, were derived from two preventive programs targeting a high-risk population. Cost-effectiveness was compared between chemoprevention with (13)C urea breath testing followed by Helicobacter pylori (H. pylori) eradication and high-risk surveillance based on serum pepsinogen measurement and confirmed by endoscopy. The main outcome measure was cost per life-year gained with a 3% annual discount rate.

RESULTS

The incremental cost-effectiveness ratio (ICER) for once-only chemoprevention at age 30 years versus no screening was U.S. $17,044 per life-year gained. Eradication of H. pylori at later age or with a periodic scheme yielded a less favorable result. Annual high-risk screening at age of 50 years versus no screening resulted in an ICER of U.S. $29,741 per life-year gained. The ICERs of surveillance did not substantially vary with different initial ages or interscreening intervals. Chemoprevention could be dominated by high-risk surveillance when the initial age was older than 44 years. Otherwise, chemoprevention was more cost-effective than high-risk surveillance, either at ceiling ratios of U.S. $15,762 or up to U.S. $50,000. The relative cost-effectiveness was most sensitive to the infection rate of H. pylori and proportion of early gastric cancer in all detectable cases.

CONCLUSIONS

Early H. pylori eradication once in lifetime seems more cost-effective than surveillance strategy. However, the choice is still subject to the risk of infection, detectability of early gastric cancer, and timing of intervention.

Optimal length of triple therapy for H pylori eradication in a population with high prevalence of infection in Chile

AIM: To compare the efficacy of 7-d versus 14-d triple therapy for the treatment of H pylori infection in Chile, with a prevalence of 73% in general population.

METHODS: H pylori-infected patients diagnosed by rapid urease test, with non-ulcer dyspepsia or peptic ulcer disease were randomized to receive omeprazole 20 mg bid, amoxicillin 1 g bid, and clarithromycin 500 mg bid for 7 (OAC7) or 14 (OAC14) d. Primary outcome was eradication rate 6 wk after the treatment. Subgroup analysis was carried out considering the eradication rate among patients with or without peptic ulcer disease and eradication rate among smokers or non-smokers.

RESULTS: One hundred and thirty-one patients were randomized to OAC7 (n = 69) or OAC14 (n = 62). The overall eradication rate (intention-to-treat) was 78.3% in OAC7 and 85.5% in OAC14 groups, without a significant difference (P =0.37). No significant difference in the eradication rate was found among the patients with peptic ulcer disease (n = 31) between the OAC7 group (85.7%) and OAC14 group (87.5%). However, smokers had an obviously lower eradication rate compared to non-smokers, particularly in the OAC7 group (57.1% in smokers vs 83.6% in non-smokers; P = 0.06). Adverse effects rate were similar between both groups.

CONCLUSION: Short-term efficacy of triple therapy with OAC for 7 d is comparable to 14 d in this high-prevalence population. Longer follow-up, and studies focused to some subgroups of patients (smokers and non-ulcer patients) are necessary to support widespread use of 7-d instead of 10-14-d triple therapy in a developing country like Chile.

Progress in vaccine development against Helicobacter pylori

Based on the very high prevalence of diseases caused by Helicobacter pylori, particularly in the developing world, and the rapid emergence of antibiotic resistance among clinical isolates, there is a strong rationale for an effective vaccine against H. pylori. In this review we describe recent promising candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori, as well as studies to identify immune responses that are related to protection in experimental animals. We also describe identification of different types of immune responses that may be related to protection against symptoms based on comparisons of H. pylori-infected patients with duodenal ulcers or gastric cancer and asymptomatic carriers. We conclude that there is still a strong need to clarify the main protective immune mechanisms against H. pylori as well as to identify a cocktail of strong protective antigens, or recombinant bacterial strains that express such antigens, that could be administered by a regimen that gives rise to effective immune responses in humans.

Precise role of H pylori in duodenal ulceration

The facts that H pylori infection is commoner in duodenal ulcer (DU) patients than in the normal population, and that eradication results in most cases being cured, have led to the belief that it causes DU. However, early cases of DU are less likely than established ones to be infected. H pylori-negative cases are usually ascribed to specific associated factors such as non-steroidal anti-inflammatory drugs (NSAIDs), Crohn's disease, and hypergastrinaemia, but even after excluding these, several H pylori-negative cases remain and are particularly common in areas of low prevalence of H pylori infection. Moreover, this incidence of H pylori negative DU is not associated with a fall in overall DU prevalence when compared with countries with a higher H pylori prevalence. In countries with a high H pylori prevalence there are regional differences in DU prevalence, but no evidence of an overall higher prevalence of DU than in countries with a low H pylori prevalence. There is no evidence that virulence factors are predictive of clinical outcome. After healing following eradication of H pylori infection DU can still recur. Medical or surgical measures to reduce acid output can lead to long-term healing despite persistence of H pylori infection. Up to half of cases of acute DU perforation are H pylori negative. These findings lead to the conclusion that H pylori infection does not itself cause DU, but leads to resistance to healing, i.e., chronicity. This conclusion is shown not to be incompatible with the universally high prevalence of DU compared with controls.

Helicobacter pylori occurrence and transmission: a family affair?

About half of the world's population is estimated to be infected with Helicobacter pylori, a gastric bacterium that contributes to the development of peptic ulcer disease and gastric cancer. H. pylori is more prevalent in low-income areas of the world and social and economic development decreases the prevalence as reflected in comparisons both within and between countries. The infection is typically acquired in early childhood and once established commonly persists throughout life unless treated. Person-to-person transmission within the family appears to be the predominant mode of transmission, particularly from mothers to children and among siblings, indicating that intimate contact is important. The route of transmission is uncertain, but the gastro-oral, oral-oral and faecal-oral routes are likely possibilities. Hence, gastroenteritis may facilitate dissemination of the infection. The community and environment may play additional roles for H. pylori transmission in some (low-income) settings. Furthermore, host and bacterial factors may modify the probabilities of acquisition and persistence of the infection. The understanding of H. pylori occurrence and transmission is of practical importance if future study deems prevention of the infection desirable in some high-prevalence populations. The present paper reviews aspects of H. pylori occurrence and transmission with an emphasis on household factors.

Helicobacter pylori recurrence in patients with duodenal ulcer: Clinical, endoscopic, histologic, and genotypic aspects. A 10-year Brazilian series

BACKGROUND

Recurrence infection following successful eradication of Helicobacter pylori is usually low, except for countries with high prevalence of H. pylori. The aim of this study was to verify H. pylori recurrence rate in patients with duodenal ulcer after eradication and the possible relationship with environmental factors, histologic pattern of the mucosa and bacterial genotype.

MATERIALS AND METHODS

One-hundred and ninety-four patients with an active duodenal ulcer and who were successfully treated for H. pylori infection from 1990 to 1999 were studied. A questionnaire was answered about their living conditions, and a 14C-urea breath test was performed. Patients with a positive breath test underwent an upper endoscopy to investigate for possible ulcer recurrence; gastric biopsy samples were than collected for rapid urease test and for histologic assessment. H. pylori vacA and cagA genotype was determined by polymerase chain reaction in those samples with positive urease test.

RESULTS

H. pylori infection was detected in 11 patients (recurrence rate of 5.7%) that were not associated with the type of bacterial virulence. In 10 patients the ulcer was healed and all of them were clinically asymptomatic. In eight, histology showed an intensification of gastritis. All 11 patients had adequate housing and sanitary conditions and no other risk for H. pylori recurrence was identified.

CONCLUSIONS

The recurrence rate of H. pylori in Brazil was higher than that reported in developed countries, but lower than usually reported in developing ones. Ulcer relapse rarely occurs even in long-term follow up.

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.

Recurrence of Helicobacter pylori infection after several eradication therapies: long-term follow-up of 1000 patients

AIM

To study the incidence of Helicobacter pylori recurrence, its chronological aspects, and the variables that might influence it.

METHODS

A total of 1000 patients in whom H. pylori had been eradicated were prospectively studied. Therapies were classified as low and high efficacy regimens. Four to eight weeks after completion of therapy, 13C-urea-breath-test was performed, and it was repeated yearly up to 5 years. In some patients, endoscopy with biopsies was also performed to confirm H. pylori eradication.

RESULTS

A total of 1000 patients were included, giving 2744 patient-years of follow-up. Seventy-one H. pylori recurrences were observed (2.6% per patient-year). Probability of being H. pylori-negative at 1 year was 94.7%, and at 5 years 90.7%. In the multivariate analysis, low age (OR: 1.84; 95% CI: 1.04-3.26) and low efficacy therapies (OR: 2.5; 1.23-5.04) correlated with 1-year H. pylori recurrence. Differences were observed when Kaplan-Meier curves were compared depending on age and therapy regimen.

CONCLUSION

Risk of posteradication H. pylori recurrence is higher during the first year, which suggests that most recurrences during this period are recrudescence and not true reinfections. H. pylori recurrence is more frequent in younger patients and in those treated with low efficacy therapies, but is exceptional if high efficacy therapies are used, in which case post-therapy eradication can be safely confirmed at 4 weeks with 13C-urea-breath-test.

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.

EFFICACY AND LONG-TERM OUTCOME OF GASTRITIS THERAPY IN CHEETAHS (ACINONYX JUBATUS)

A prospective clinical trial evaluating efficacy and long-term outcome of treatments for lymphoplasmacytic gastritis in cheetahs (Acinonyx jubatus) was conducted. The study evaluated efficacy of 11 different antibiotic and antiinflammatory treatment protocols in 32 cheetahs (19 male, 13 female) for reducing gastric inflammation and Helicobacter colonization and monitored the course of disease through histologic grading of gastric biopsies. All cheetahs were biopsied up to I wk before treatment and then rebiopsied within 1 mo after treatment. Most animals were reassigned to a second treatment regimen within 6 mo. Each animal received from one to three treatments during the study period. After the trial, gastric biopsies were obtained from each cheetah annually until death or transfer from the facility to assess disease progression. The trial and follow-up period spanned 10 yr. At onset of the trial, all 32 cheetahs had some degree of gastritis, and 26 cheetahs (81%) were colonized with Helicobacter. Inflammatory lesions worsened regardless of treatment or the presence of Helicobacter. No treatment had a significant effect on inflammatory changes except the lansoprazole/clarithromycin/amoxicillin treatment group, which produced a short-term decrease in inflammation when compared to controls. Prednisone had no effect on gastric inflammation. Overall, 65% of colonized cheetahs were initially cleared of histologic evidence of Helicobacter by treatment, with short-term eradication occurring in 100% of the animals treated with omeprazole/clarithromycin/amoxicillin or tetracycline/metronidazole/Pepto-Bismol for 28 days. Long-term follow-up of treated animals in this study clearly demonstrated that these treatments had little effect on life-long progression of gastritis or on Helicobacter burden in individual cheetahs, although some treatments provided short-term reduction in gastritis and Helicobacter. These results provide evidence that Helicobacter alone is not the cause of gastritis in cheetahs and do not support the use of antibacterial treatments in cheetahs unless significant clinical signs (e.g., frequent vomiting/regurgitation, weight loss) are apparent.