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

Recurrence of Helicobacter pylori following successful eradication and clinical outcomes in Korean patients

BACKGROUND/AIMS

Helicobacter pylori (H. pylori) infections can recur as either recrudescence or reinfection. At a time when the decline in the eradication rate is becoming evident, increases in the rate of recurrence are concerning. In addition, there are no guidelines for selecting an eradication regimen for H. pylori recurrence.

MATERIALS AND METHODS

A total of 996 H. pylori-infected patients treated with proton-pump inhibitor-based triple eradication therapy between 2017 and 2022 were enrolled in the study, and successful eradication therapies were confirmed by the 13 C-urea breath test. When retested within 1 year after successful eradication, analysis related to recrudescence was performed, and when retested after 1 year, analysis related to reinfection was performed. We reviewed the medical records and treatment outcomes of patients with H. pylori reinfection after successful eradication.

RESULTS

The recrudescence rate was 3.9% (9/228), and the reinfection rate was 3.7% (36/970 person-year). The frequency of reinfection reached 5.9% per person-year within the first 24 months and 2.0%-2.4% per person-year thereafter. In multivariate factor analysis, reinfection was significantly higher in patients with non-ulcer dyspepsia (p < 0.01). At first-line therapy for reinfection, the eradication rate of standard triple therapy (STT) was 50.0% (16/32). The eradication rate of second-line bismuth quadruple therapy was 81.3% (13/16), and levofloxacin-based rescue therapy was 66.7% (2/3).

CONCLUSION

Re-treatment of patients with H. pylori reinfection with STT had limited efficacy. Prospective research is needed to determine whether patients with non-ulcer dyspepsia are vulnerable to reinfection.

Changes in Gastric Pathology after H. pylori Treatment in Community-Driven Research Aimed at Gastric Cancer Prevention

Community-driven projects have characterized Helicobacter pylori (Hp) infection in Indigenous communities in the Northwest Territories (NT) and Yukon (YT), Canada. These projects address concerns about the frequent diagnosis of Hp infection among community members and its relation to gastric cancer deaths, perceived to occur with alarming frequency in this region. Projects included breath-test screening for Hp infection, gastroscopy with gastric biopsies, and treatment to eliminate Hp infection. Previous project results showed a high prevalence of stomach pathologies associated with increased cancer risk among Hp-positive participants at baseline. This analysis describes changes in precancerous gastric pathologies in project participants who had gastroscopy before baseline treatment during 2008-2013 and again in 2017. Throughout the study period, the same pathologist graded Hp density, active gastritis, chronic gastritis, atrophic gastritis, and intestinal metaplasia using the updated Sydney System. Of 310 participants from three communities with baseline pathology data, 69 had follow-up pathology data. Relative to baseline, the prevalence of Hp infection and precancerous gastric pathology was substantially lower at follow-up; most participants who were Hp-positive at baseline and Hp-negative at follow-up had reduced severity of active, chronic, and/or atrophic gastritis at follow-up. Though follow-up numbers are small, these results yield evidence that successful Hp treatment has the potential to reduce the risk of gastric cancer in Arctic Indigenous communities.

The Alaska Native Tumour Registry: fifty years of cancer surveillance data for Alaska Native people

Like other Indigenous Circumpolar populations, Alaska Native (AN) people experience different patterns of cancer than their non-Indigenous counterparts. Every 5 years, the Alaska Native Tumour Registry releases a comprehensive report on cancer among AN people; this study provides 50 years of cancer surveillance data. Five-year annual-average age-adjusted incidence rates were calculated for time-periods ranging 1969-2018. AN data were compared with data for US whites (SEER 9). Mortality rates were calculated for 1994-2018 using data from the National Center for Health Statistics. During 2014-2018, there were 2,401 cases of invasive cancer among AN people. Among these, the most commonly diagnosed cancers were colorectal (405 cases, 17% of all cancers), lung and bronchus (373 cases, 16% of all cancers), and female breast (340 cases, 14% of all cancers). Lung cancer was the leading cause of cancer death, followed by colorectal and female breast cancers. These leading cancers are screenable, and preventable through lifestyle modifications including tobacco cessation, healthy eating and engaging in physical activity. These data provide important information to support cancer prevention and control among AN people. Cancer surveillance has been a valuable tool throughout the Circumpolar North to support reducing the burden of cancer among Indigenous populations.Abbreviations: ANAI: Alaska Native/American Indian; AN: Alaska Native; USW: U.S. White(s); ANMC: Alaska Native Medical Center; ANTR: Alaska Native Tumour Registry; IR: Incidence Rate; CI: Confidence Interval; RR: Rate Ratio; ICD-O-3: International Classification of Diseases for Oncology - Third Edition; SEER: Surveillance, Epidemiology and End Results.

Incidence of and Trends in the Leading Cancers With Elevated Incidence Among American Indian and Alaska Native Populations, 2012-2016

Cancer incidence varies among American Indian and Alaska Native (AI/AN) populations, as well as between AI/AN and White populations. This study examined trends for cancers with elevated incidence among AI/AN compared with non-Hispanic White populations and estimated potentially avoidable incident cases among AI/AN populations. Incident cases diagnosed during 2012-2016 were identified from population-based cancer registries and linked with the Indian Health Service patient registration databases to improve racial classification of AI/AN populations. Age-adjusted rates (per 100,000) and trends were calculated for cancers with elevated incidence among AI/AN compared with non-Hispanic White populations (rate ratio of >1.0) according to region. Trends were estimated using joinpoint regression analyses. Expected cancers were estimated by applying age-specific cancer incidence rates among non-Hispanic White populations to population estimates for AI/AN populations. Excess cancer cases among AI/AN populations were defined as observed minus expected cases. Liver, stomach, kidney, lung, colorectal, and female breast cancers had higher incidence rates among AI/AN populations across most regions. Between 2012 and 2016, nearly 5,200 excess cancers were diagnosed among AI/AN populations, with the largest number of excess cancers (1,925) occurring in the Southern Plains region. Culturally informed efforts could reduce cancer disparities associated with these and other cancers among AI/AN populations.

Gastric Cancer Among American Indian and Alaska Native Populations in the United States, 2005-2016

INTRODUCTION

American Indian and Alaska Native (AI/AN) populations have higher gastric cancer rates than the general US population. This study provides a comprehensive overview of incidence rates among AI/AN persons during 2005-2016 compared with non-Hispanic whites (whites).

METHODS

Population-based cancer registry data for 2005-2016 were linked with the Indian Health Service patient registration databases to address racial misclassification. Age-adjusted gastric cancer incidence rates were expressed per 100,000 per year. Incidence and trend analyses were restricted to purchased/referred care delivery area counties in 6 geographic regions, comparing gastric cancer incidence rates for AI/AN vs white populations in the United States.

RESULTS

Gastric cancer rates were higher in the AI/AN compared with white populations in nearly every US region. Incidence rates for central/distal portions of the stomach were higher in AI/AN individuals compared with whites. Rates of later stage gastric cancer were higher in AI/AN populations overall and in every region except the Pacific Coast and East. Incidence rates decreased significantly over time in both populations. Declining rates in the AI/AN populations were driven by changes in the Pacific Coast and Northern Plains regions.

DISCUSSION

AI/AN populations have a disproportionately high incidence of gastric cancer, especially in Alaska. High incidence in the central/distal portions of the stomach among AI/AN populations likely reflects a high prevalence of Helicobacter pylori infection in these populations. These data can be used to develop interventions to reduce risk factors and improve access to health services among AI/AN people at high risk for gastric cancer.

Planning mass eradication of Helicobacter pylori infection for indigenous Taiwanese peoples to reduce gastric cancer

BACKGROUND AND AIM

The aim of this study is to identify gastric cancer burden in Indigenous Taiwanese peoples and conduct a project to evaluate how to reduce the disparities most effectively in Indigenous communities.

METHODS

First, we quantified the health disparities in gastric cancer in Indigenous peoples using data from the cancer registries during the period of 2006-2014. Second, we identified parameters that might be associated with Helicobacter pylori infection or help identify a good eradication strategy.

RESULTS

Gastric cancer incidence (24.4 vs 12.3 per 100 000 person-years) and mortality rates (15.8 vs 6.8 per 100 000 person-years) were higher in Indigenous than in non-Indigenous, with 2.19-fold (95% confidence interval [CI]: 2.06-2.33) and 2.47-fold (2.28-2.67) increased risk, respectively. In Indigenous communities, H. pylori infection was more prevalent in Indigenous than in non-Indigenous (59.4% vs 31.5%, P < 0.01). Regression analyses consistently showed that either the mountain or plain Indigenous had 1.89-fold (95% CI: 1.34-2.66) and 1.73-fold (95% CI: 1.24-2.41) increased risk for H. pylori infection, respectively, as compared with non-Indigenous, adjusting for other baseline characteristics. The high infection rates were similarly seen in young, middle-aged, and older adults. Program eradication rates using clarithromycin-based triple therapy were suboptimal (73.7%, 95% CI: 70.0-77.4%); the habits of smoking (1.70-fold, 95% CI: 1.01-2.39) and betel nut chewing (1.54-fold, 95% CI: 0.93-2.16) were associated with the higher risk of treatment failure.

CONCLUSION

Gastric cancer burden is higher in Indigenous Taiwanese peoples than in their non-Indigenous counterparts. Eliminating the prevalent risk factor of H. pylori infection is a top priority to reduce this health disparity.

Presence of cagPAI genes and characterization of vacA s, i and m regions in Helicobacter pylori isolated from Alaskans and their association with clinical pathologies

Introduction. Gastric cancer is a health disparity in the Alaska Native people. The incidence of Helicobacter pylori infection, a risk factor for non-cardia gastric adenocarcinoma, is also high. Gastric cancer is partially associated with the virulence of the infecting strain.Aim. To genotype the vacA s, m and i and cag pathogenicity island (cagPAI) genes in H. pylori from Alaskans and investigate associations with gastropathy.Methodology. We enrolled patients with gastritis, peptic ulcer disease (PUD) and intestinal metaplasia (IM) in 1998-2005 and patients with gastric cancer in 2011-2013. Gastric biopsies were collected and cultured and PCR was performed to detect the presence of the right and left ends of the cagPAI, the cagA, cagE, cagT and virD4 genes and to genotype the vacA s, m and i regions.Results. We recruited 263 people; 22 (8 %) had no/mild gastritis, 121 (46 %) had moderate gastritis, 40 (15%) had severe gastritis, 38 (14 %) had PUD, 30 (11 %) had IM and 12 (5 %) had gastric cancer. H. pylori isolates from 150 (57%) people had an intact cagPAI; those were associated with a more severe gastropathy (P≤0.02 for all comparisons). H. pylori isolates from 77 % of people had either the vacA s1/i1/m1 (40 %; 94/234) or s2/i2/m2 (37 %; 86/234) genotype. vacA s1/i1/m1 was associated with a more severe gastropathy (P≤0.03 for all comparisons).Conclusions. In this population with high rates of gastric cancer, we found that just over half of the H. pylori contained an intact cagPAI and 40 % had the vacA s1/i1/m1 genotype. Infection with these strains was associated with a more severe gastropathy.

Inference from the analysis of genetic structure of Helicobacter pylori strains isolates from two paediatric patients with recurrent infection

Background

Helicobacter pylori recurrence after successful eradication is an important problem. Children are particularly vulnerable to reinfection, by intrafamilial transmission which facilitates the acquisition or recombination of new genetic information by this bacterium. We investigated the evolutionary dynamics of 80 H. pylori strains isolated from two paediatric patients with recurrent infection (recrudescence and reinfection).

Results

We characterized the virulence genes vacA (s1, m1, s2, and m2), cagA, cagE, and babA2 and performed multilocus sequence typing (MLST) on 7 housekeeping genes (atpA, efp, ureI, ppa, mutY, trpC, and yphC) to infer the evolutionary dynamics of the H. pylori strains through phylogenetic and genealogic inference analyses, genetic diversity analysis and the exploration of recombination events during recurrent infections. The virulence genotype vacAs1m1/cagA+/cagE+/babA2 was present at a high frequency, as were the EPIYA motifs EPIYA-A, −B and -C. Furthermore, the housekeeping genes of the H. pylori strains exhibited high genetic variation, comprising 26 new alleles and 17 new Sequence Type (ST). In addition, the hpEurope (76.5%) and hspWAfrica (23.5%) populations predominated among the paediatric strains. All strains, regardless of their ancestral affiliation, harboured western EPIYA motifs.

Conclusions

This study provides evidence of the evolutionary dynamics of the H. pylori strains in two paediatric patients during recrudescence and reinfection events. In particular, our study shows that the strains changed during these events, as evidenced by the presence of different STs that emerged before and after treatment; these changes may be due to the accumulation of mutations and recombination events during the diversification process and recolonization of the patients by different genotypes.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1554-z) contains supplementary material, which is available to authorized users.

Rate and predictive factors of Helicobacter pylori recurrence: Analysis of a screening cohort

BACKGROUND/AIM

The aim of the study was to identify the recurrence rate of Helicobacter pylori after successful eradication in an endemic area and investigate baseline and clinical factors related to the recurrence.

PATIENTS AND METHODS

H. pylori infected patients from a screening cohort of National Cancer Center between 2007 and 2012 were enrolled in the study. A total of 647 patients who were confirmed to be successfully eradicated were annually followed by screening endoscopy and rapid urease test. Median follow-up interval was 42 months. Annual recurrence rate of H. pylori was identified. Demographics, clinical factors, and endoscopic findings were compared between H. pylori recurrence group and persistently eradicated group (control group).

RESULTS

H. pylori recurrence was observed in 21 (3.25%) patients. Its annual recurrence rate was 0.91% (1.1% in males and 0.59% in females). Mean age was higher in the recurrence group than that in the control group (55.9 vs 50.7, P = 0.006). Median follow-up was shorter in the recurrence group than that in the control group (34 vs. 42.5 months, P = 0.031). In multivariate analysis, OR for H. pylori recurrence was 1.08 per each increase in age (P = 0.012). Adjusted ORs for H. pylori recurrence were 0.20 (95% CI: 0.06-0.69) and 0.25 (95% CI: 0.08-0.76) in age groups of 50-59 years and less than 50 years, respectively, compared to the group aged 60 years or older.

CONCLUSION

H. pylori recurrence rate in Korea is very low after successful eradication. Advanced age is at increased risk for H. pylori recurrence. Thus, H. pylori treatment for patients who are under 60 years of age is more effective, leading to maintenance of successful eradication status.

Helicobacter pylori, transmission routes and recurrence of infection: state of the art

Helicobacter pylori (H. pylori) infection is one of the most common infection in humans, affecting more than half of the population. The prevalence of the infection varies widely in rural developing areas (more than 80%) compared to urban developed ones (less than 40%), as a consequence of different socioeconomic and hygienic conditions. H. pylori infection is usually acquired during childhood; infected people usually remain asymptomatic, but about 30% of individuals may develop mild to severe upper gastrointestinal diseases such as gastritis, peptic ulcer, gastric cancer or MALT lymphoma. The transmission route is not clear yet; the person-to-person transmission, especially within the same family appears to be prevalent, but also environmental contamination is possible. The eradication without a specific therapeutic regimen is very unlikely and the reinfection rate after an effective eradication therapy is quite rare. The reinfection rate will increase if there are family members affected.

H. pylori-associated pathologic findings among Alaska native patients

Helicobacter pylori infection is common among Alaska native (AN) people, however scant gastric histopathologic data is available for this population. This study aimed to characterise gastric histopathology and H. pylori infection among AN people. We enrolled AN adults undergoing upper endoscopy. Gastric biopsy samples were evaluated for pathologic changes, the presence of H. pylori, and the presence of cag pathogenicity island-positive bacteria. Of 432 persons; two persons were diagnosed with gastric adenocarcinoma, two with MALT lymphoma, 40 (10%) with ulcers, and 51 (12%) with intestinal metaplasia. Fifty-five per cent of H. pylori-positive persons had cag pathogenicity island positive bacteria. The gastric antrum had the highest prevalence of acute and chronic moderate-severe gastritis. H. pylori-positive persons were 16 and four times more likely to have moderate-severe acute gastritis and chronic gastritis (p < 0.01), respectively. An intact cag pathogenicity island positive was correlated with moderate-severe acute antral gastritis (53% vs. 31%, p = 0.0003). H. pylori-positive persons were more likely to have moderate-severe acute and chronic gastritis compared to H. pylori-negative persons. Gastritis and intestinal metaplasia were most frequently found in the gastric antrum. Intact cag pathogenicity island positive was correlated with acute antral gastritis and intestinal metaplasia.

Antimicrobial resistance among Helicobacter pylori isolates in Alaska, 2000-2016

OBJECTIVES

Alaska Natives experience a high burden of Helicobacter pylori infection and concomitant high rates of gastric cancer. Additionally, the prevalence of antimicrobial-resistant H. pylori has been shown to be high in Alaska. In this study, antimicrobial resistance over time among sentinel surveillance isolates was evaluated and risk factors for carrying antimicrobial-resistant H. pylori were assessed.

METHODS

Through Alaska's H. pylori sentinel surveillance system, antral and fundal biopsies from Alaska Native patients undergoing esophagogastroduodenoscopy for clinical indications during 2000-2016 were collected and cultured. For positive cultures, minimum inhibitory concentrations (MICs) of metronidazole, amoxicillin, clarithromycin, tetracycline and levofloxacin were determined.

RESULTS

A total of 800 H. pylori isolates obtained from 763 patients were tested. Resistance to metronidazole was most common (342/800; 42.8%), followed clarithromycin (238/800; 29.8%), both clarithromycin and metronidazole (128/800; 16.0%) and levofloxacin (113/800; 14.1%). Low proportions of isolates were resistant to amoxicillin and tetracycline. Levofloxacin resistance increased between 2000 and 2016 (P<0.001), but resistance to other antimicrobials did not change over time. Metronidazole and clarithromycin resistance were more common among women (P<0.001 for both), whilst levofloxacin resistance was more common among those with an urban residence (P=0.003). Metronidazole and levofloxacin resistance were more common among older patients (P<0.05).

CONCLUSION

Between 2000 and 2016, a large percentage of H. pylori isolates received by the Alaska Sentinel Surveillance System demonstrated resistance to common antimicrobials. The surveillance system provides valuable information for clinicians to make informed treatment choices for patient with H. pylori.

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.

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 infection and markers of gastric cancer risk in Alaska Native persons: a retrospective case-control study

BACKGROUND

Alaska Native persons experience gastric cancer incidence and mortality rates that are three to four times higher than in the general United States population.

OBJECTIVE

To evaluate pepsinogen I, pepsinogen I/II ratio, anti-Helicobacter pylori and cytotoxin-associated gene A (CagA) antibody levels, and blood group for their associations with gastric cancer development in Alaska Native people.

METHODS

The present analysis was a retrospective case-control study that matched gastric cancers reported to the Alaska Native Tumor Registry from 1969 to 2008 to three controls on known demographic risk factors for H pylori infection, using sera from the Alaska Area Specimen Bank. Conditional logistic regression evaluated associations between serum markers and gastric cancer.

RESULTS

A total of 122 gastric cancer cases were included, with sera predating cancer diagnosis (mean = 13 years) and 346 matched controls. One hundred twelve cases (91.8%) and 285 controls (82.4%) had evidence of previous or ongoing H pylori infection as measured by anti-H pylori antibody levels. Gastric cancer cases had a 2.63-fold increased odds of having positive anti-H pylori antibodies compared with their matched controls (P=0.01). In a multivariate model, noncardia gastric cancer (n=94) was associated with anti-H pylori antibodies (adjusted OR 3.92; P=0.004) and low pepsinogen I level (adjusted OR 6.04; P=0.04). No association between gastric cancer and blood group, anti-CagA antibodies or pepsinogen I/II ratio was found.

CONCLUSION

Alaska Native people with gastric cancer had increased odds of previous H pylori infection. Low pepsinogen I level may function as a precancer marker for noncardia cancer.

Role of dental plaque, saliva and periodontal disease in Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is one of the most common bacterial infections in humans. Although H. pylori may be detected in the stomach of approximately half of the world's population, the mechanisms of transmission of the microorganism from individual to individual are not yet clear. Transmission of H. pylori could occur through iatrogenic, fecal-oral, and oral-oral routes, and through food and water. The microorganism may be transmitted orally and has been detected in dental plaque and saliva. However, the role of the oral cavity in the transmission and recurrence of H. pylori infection has been the subject of debate. A large number of studies investigating the role of oral hygiene and periodontal disease in H. pylori infection have varied significantly in terms of their methodology and sample population, resulting in a wide variation in the reported results. Nevertheless, recent studies have not only shown that the microorganism can be detected fairly consistently from the oral cavity but also demonstrated that the chances of recurrence of H. pylori infection is more likely among patients who harbor the organism in the oral cavity. Furthermore, initial results from clinical trials have shown that H. pylori-positive dyspeptic patients may benefit from periodontal therapy. This paper attempts to review the current body of evidence regarding the role of dental plaque, saliva, and periodontal disease in H. pylori infection.

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.

Helicobacter pylori incidence and re-infection in the Aklavik H. pylori Project

Background

The Aklavik H. pylori Project (AHPP) (www.canhelpworkinggroup.ca) is a community-driven project examining Helicobacter pylori infection and its influence on health in a diverse Aboriginal community in the Northwest Territories. Initial research revealed that 58% of 333 participants who underwent a urea breath test (UBT) between 2007 and 2010 were H. pylori-positive. From 2008 to 2010, we offered treatment to H. pylori-positive participants and 113 consented to this treatment.

Objective

We estimated H. pylori incidence in AHPP participants who initially tested negative and the re-infection frequency in initially positive participants who were successfully treated to clear the infection.

Methods

Participants who were initially H. pylori-negative or negative after treatment during 2008–2010 were eligible for inclusion. From November 2011 to June 2012, participants were offered a UBT and the samples were analyzed using infrared spectroscopy (IRIS). Participants with a positive test result were classified as new cases for estimating incidence among participants testing negative at baseline and re-infection among those successfully treated for H. pylori infection.

Results

Among 38 initially negative participants, follow-up UBT showed that 33 remained negative, 3 were positive, and 2 had uncertain status. The estimated incidence proportion during the follow-up period was 8.3% (95% CI: 1.8–22.0%). Among 43 participants with a negative post-treatment UBT, 41 remained negative and 2 were positive. The estimated re-infection proportion during the follow-up period was 4.7% (95% CI: 0.6–16.0%). The frequency of new cases was similar in males and females. Aboriginal participants had a combined re-infection/incidence rate of 2.4% per year (95% CI: 0.8–5.9% per year). All 9 non-Aboriginal participants remained free from infection throughout the study period, as did all 23 participants aged 55 years and above.

Conclusions

The AHPP has substantially reduced the burden of infection in Aklavik since 2008. Continued monitoring, treatment, community engagement and knowledge translation activities are needed to ensure a lasting benefit of the project.

The effect of Helicobacter pylori infection on iron stores and iron deficiency in urban Alaska Native adults

BACKGROUND

Helicobacter pylori (H. pylori) infection has been correlated with low serum ferritin and iron deficiency. As a secondary analysis of a study of H. pylori reinfection, we investigated the association of H. pylori infection and the effect of its eradication on serum ferritin and iron deficiency.

METHODS

Alaska Native adults undergoing esophagogastroduodenoscopy had sera collected and a (13) C urea breath test (UBT) was performed. Those H. pylori positive were treated with an antibiotic regimen; those who tested negative 2 months after treatment were evaluated at 4, 6, 12, and 24 months by UBT and serum ferritin with an immunoradiometric assay. We excluded persons from further analysis if they were prescribed iron by their provider.

RESULTS

We measured serum ferritin for 241 persons; 121/241 were H. pylori positive. The geometric mean ferritin (GMF) for persons with and without H. pylori infection was 37 μg/L and 50 μg/L, respectively (p = .04). At enrollment, 19/121 H. pylori-positive persons had iron deficiency compared with 8/120 H. pylori negative (p = .02). Among 66 persons tested at 24 months, the GMF was higher at 24 months (49.6 μg/L) versus enrollment (36.5 μg/L; p = .02). Six of 11 persons with iron deficiency at enrollment no longer had iron deficiency and had a higher GMF (p = .02) 24 months after treatment.

CONCLUSIONS

H. pylori infection was correlated with lower serum ferritin and iron deficiency. After H. pylori eradication, serum ferritin increased and approximately half of persons resolved their iron deficiency. Testing for H. pylori infection and subsequent treatment of those positive could be considered in persons with unexplained iron deficiency.

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.

Diagnostic accuracy of tests for Helicobacter pylori in an Alaska Native population

AIM: To evaluate the accuracy of two non-invasive tests in a population of Alaska Native persons. High rates of Helicobacter pylori (H. pylori) infection, H. pylori treatment failure, and gastric cancer in this population necessitate documentation of infection status at multiple time points over a patient’s life.

METHODS: In 280 patients undergoing endoscopy, H. pylori was diagnosed by culture, histology, rapid urease test, ¹³C urea breath test (UBT), and immunoglobulin G antibodies to H. pylori in serum. The performances of ¹³C-UBT and antibody test were compared to a gold standard defined by a positive H. pylori test by culture or, in case of a negative culture result, by positive histology and a positive rapid urease test.

RESULTS: The sensitivity and specificity of the ¹³C-UBT were 93% and 88%, respectively, relative to the gold standard. The antibody test had an equivalent sensitivity of 93% with a reduced specificity of 68%. The false positive results for the antibody test were associated with previous treatment for an H. pylori infection [relative risk (RR) = 2.8]. High levels of antibodies to H. pylori were associated with chronic gastritis and male gender, while high scores in the ¹³C-UBT test were associated with older age and with the H. pylori bacteria load on histological examination (RR = 4.4).

CONCLUSION: The ¹³C-UBT outperformed the antibody test for H. pylori and could be used when a non-invasive test is clinically necessary to document treatment outcome or when monitoring for reinfection.

Alaska sentinel surveillance study of Helicobacter pylori isolates from Alaska Native persons from 2000 to 2008

Helicobacter pylori infection is more common in Alaska Native persons than in the general U.S. population, with seroprevalence to H. pylori approaching 75%. Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among H. pylori isolates. We analyzed H. pylori data from the Centers for Disease Control and Prevention's sentinel surveillance in Alaska from January 2000 to December 2008 to determine the proportion of culture-positive biopsy specimens with antimicrobial resistance from Alaska Native persons undergoing endoscopy. The aim of the present study was to monitor antimicrobial resistance of H. pylori isolates over time and by region in Alaska Native persons. Susceptibility testing of H. pylori isolates to metronidazole, clarithromycin, amoxicillin, and tetracycline was performed using agar dilution. Susceptibility testing for levofloxacin was performed by Etest. Overall, 45% (532/1,181) of persons undergoing upper endoscopy were culture positive for H. pylori. Metronidazole resistance was demonstrated in isolates from 222/531 (42%) persons, clarithromycin resistance in 159/531 (30%) persons, amoxicillin resistance in 10/531 (2%) persons, and levofloxacin resistance in 30/155 (19%) persons; no tetracycline resistance was documented. The prevalence of metronidazole, clarithromycin, and levofloxacin resistance varied by region. Female patients were more likely than male patients to demonstrate metronidazole (P < 0.05) and clarithromycin (P < 0.05) resistance. No substantial change in the proportion of persons with resistant isolates was observed over time. Resistance to metronidazole, clarithromycin, and levofloxacin is more common among H. pylori isolates from Alaska Native persons than those from elsewhere in the United States.

Characterization of Helicobacter pylori cagA and vacA genotypes among Alaskans and their correlation with clinical disease

Helicobacter pylori infection is common in Alaska. The development of severe H. pylori disease is partially determined by the virulence of the infecting strain. Here we present vacA and cagA genotype data for H. pylori strains isolated from Alaskans and their correlation with clinical disease. We enrolled patients scheduled for esophagogastroduodenoscopy and positive for H. pylori infection. Gastric biopsy specimens from the stomach antrum and fundus were cultured. We performed PCR analysis of the H. pylori vacA gene and for the presence of the cagA gene and cagA empty site. We genotyped 515 H. pylori samples from 220 Native and 66 non-Native Alaskans. We detected the cagA gene in 242/286 (85%) persons; of 222 strains that could be subtyped, 95% (212) were non-Asian cagA and 3% (6) were East Asian cagA. After removing mixed infections (n = 17), 83% of H. pylori strains had either the vacA s1m1 (120/269) or s2m2 (103/269) genotype. Sixty-six percent (68/103) of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. Infection with an H. pylori strain having the cagA gene or vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with a decreased risk of esophagitis (P = 0.003 and 0.0003, respectively). Infection with an H. pylori strain having the vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with an increased risk of peptic ulcer disease (PUD) (P = 0.003). The majority of H. pylori strains in this study carried the non-Asian cagA gene and either the vacA s1m1 or s2m2 genotype. A majority of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. There was an association of H. pylori genotype with esophagitis and PUD.

In vitro inhibition of Helicobacter pylori growth and of adherence of cagA-positive strains to gastric epithelial cells by Lactobacillus paraplantarum KNUC25 isolated from kimchi

Lactobacillus paraplantarum KNUC25 strain was isolated from overfermented kimchi, a Korean traditional food. The strain had a broad antimicrobial activity spectrum, from gram-positive to gram-negative bacteria. The aim of this study was to evaluate the activity of L. paraplantarum KNUC25 against Helicobacter pylori strains. Judged by a disc agar diffusion method, the anti-H. pylori activity existed in the cell-free supernatants (CFSs) of KNUC25. The mean diameters of growth inhibition by 10, 30, and 60 microL of a 15-fold concentrated CFS per disc were 11.2, 17.7, and 23.7 mm, respectively. The neutralized CFS lost its anti-H. pylori activity, suggesting that acidic pH in CFS may be responsible for the anti-H. pylori activity. Adherence was determined by urease activity of H. pylori adhered to gastric epithelial cell line AGS cells after co-incubation of AGS cells with CFS and H. pylori strain ATCC43504 (s1m1vacA/cagA(+)), ATCC51932 (s2m2vacA/cagA(-)), or SS1 (s2m2vacA/cagA(+)) in vitro followed by three washes by means of centrifugation with saline. Adherence of ATCC43504 or SS1 to AGS cells was reduced by about 70% after a 30-minute incubation with 30 microL of a 15-fold concentrated KNUC25 CFS, whereas that of ATCC51932 to AGS cells was not. The results show KNUC25 CFS is effective in inhibiting the growth of H. pylori, which is related to pH and the adherence of cagA-positive H. pylori to gastric cells.

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.

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.

Gastric cancer among American Indians and Alaska Natives in the United States, 1999-2004

BACKGROUND

Gastric cancer incidence rates for American Indians and Alaska Natives (AI/ANs) historically have exceeded those for non-Hispanic whites (NHWs). Previous reports may have underestimated the true burden of gastric cancer in AI/AN populations because of misclassification of AI/AN race in cancer registries.

METHODS

Population-based cancer registry data from 1999 through 2004 were used to describe gastric cancer incidence in AI/ANs and NHWs in the US. To address misclassification of race, registry data were linked with Indian Health Service administrative records, and analyses were restricted to residents of Contract Health Service Delivery Areas (CHSDA). Disease patterns were assessed for 6 geographic regions and for all regions combined. Rates were expressed per 100,000 population and were age-adjusted to the 2000 US standard population.

RESULTS

In CHSDA counties, gastric cancer incidence rates for AI/ANs were higher than the rates for NHWs across most regions. For both sexes combined, AI/AN rates ranged from 6.1 in the East region to 24.5 in Alaska; there was relatively little regional variation in NHW rates. Most patients with gastric cancer were diagnosed with late-stage disease, regardless of race, age, or sex. In some regions, cancer rates in the central/distal portions of the stomach were higher among AI/ANs than among NHWs, whereas rates in the proximal stomach were similar between the 2 populations.

CONCLUSIONS

AI/ANs are generally at greater risk for gastric cancer than NHWs. Relatively high rates of cancer in the central/distal portions of the stomach among AI/ANs in some geographic regions may indicate a disproportional burden of Helicobacter pylori-associated disease.

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 infection in Canadian and related Arctic Aboriginal populations

In 2006, the Canadian Helicobacter Study Group identified Aboriginal communities among Canadian population groups most at risk of Helicobacter pylori-associated disease. The objective of this systematic review was to summarize what is known about the H pylori-associated disease burden in Canadian and related Arctic Aboriginal populations to identify gaps in knowledge. Six health literature databases were systematically searched to identify reports on H pylori prevalence in Canadian population groups, or any topic related to H pylori in Canadian Aboriginals, Alaska Natives or Aboriginals of other Arctic regions. Identified reports were organized by subtopic and summarized in narrative form. Key data from studies of H pylori prevalence in defined populations were summarized in tabular form. A few Arctic Aboriginal communities were represented in the literature: two Canadian Inuit; one Canadian First Nation; two Greenland Inuit; one Russian Chutkotka Native; and several Alaska Native studies. These studies uniformly showed elevated H pylori prevalence; a few studies also showed elevated occurrence of H pylori-related diseases and high rates of treatment failure. Based on the evidence, it would be warranted for clinicians to relax the criteria for investigating H pylori and related diseases in patients from Arctic Aboriginal communities, and to pursue post-therapy confirmation of eradication. Additional community-based research is needed to develop public health policies for reducing H pylori-associated health risks in such communities.

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.

The relationship between previous fluoroquinolone use and levofloxacin resistance in Helicobacter pylori infection

The relationship between prior fluoroquinolone use and levofloxacin resistance in Helicobacter pylori infection is unknown. Among 125 enrolled patients, 8.8% had H. pylori isolates that were resistant to levofloxacin. Levofloxacin resistance was associated with any prior fluoroquinolone use over the previous 10 years and with the total number of fluoroquinolone courses prescribed (P<.001).

Alaska sentinel surveillance for antimicrobial resistance in Helicobacter pylori isolates from Alaska native persons, 1999-2003

BACKGROUND

Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among Helicobacter pylori isolates.

MATERIALS AND METHODS

We analyzed H. pylori data from the Centers for Disease Control and Prevention (CDC)'s sentinel surveillance in Alaska from July 1999 to June 2003 to determine the proportion of culture-positive biopsies from Alaska Native persons undergoing routine upper-endoscopy, and the susceptibility of H. pylori isolates to metronidazole [minimum inhibitory concentration (MIC) of > 8 g metronidazole/mL), clarithromycin (MIC > or = 1), tetracycline (MIC > or = 2) and amoxicillin (MIC > or = 1)] using agar dilution.

RESULTS

Nine-hundred sixty-four biopsy specimens were obtained from 687 participants; 352 (51%) patients tested culture positive. Mean age of both culture-positive and culture-negative patients was 51 years. Metronidazole resistance was demonstrated in isolates from 155 (44%) persons, clarithromycin resistance from 108 (31%) persons, amoxicillin resistance from 8 (2%) persons, and 0 for tetracycline resistance. Metronidazole and clarithromycin resistance varied by geographic region. Female patients were more likely than male subjects to show metronidazole resistance (p < .01) and clarithromycin resistance (p = .05).

CONCLUSIONS

Resistance to metronidazole and clarithromycin is more common among H. pylori isolates from Alaska Native persons when compared with those from elsewhere in the USA.

Dynamics of Helicobacter pylori-specific immunoglobulin G for 2 years after successful eradication of Helicobacter pylori infection in an American Indian and Alaska Native population

Helicobacter pylori antibodies were measured over 24 months in American Indian and Alaska Native persons who cleared their infections. Two months after treatment, 82% of H. pylori-negative persons remained seropositive. While there were declines in H. pylori antibodies for 12 months, after 24 months 71% of persons remained seropositive.