Extremely high prevalence of Helicobacter pylori infection in Bhutan

C-Kit Immunohistochemical Expression as a Complementary Method to Assess Mast Cell Density in Helicobacter pylori-Mediated Gastritis

INTRODUCTION

Chronic gastritis is a group of conditions commonly characterized by stomach lining inflammation. The study aimed to investigate the clinical and pathological aspects that play a role in its development. Additionally, the study examines the use of CD117 as an immunohistochemistry marker in evaluating mast cell density (MCD).

METHODS

This retrospective, cross-sectional study was conducted in Iraqi Kurdistan with a sample size of 380 patients. Patient data included gastritis type, neutrophil infiltration severity, mononuclear cell infiltration within the lamina propria, intestinal metaplasia, and glandular atrophy, which were categorized and given a score. The CD117 level was identified using an anti-human rabbit polyclonal antibody.

RESULTS

A statistically significant association was revealed between Helicobacter pylori-mediated gastritis and non-specific gastritis with age, activity, H. pylori and MCD, dysplasia, and malignancy. Meanwhile, no association was found with gender, inflammatory infiltrate, intestinal metaplasia, and glandular atrophy. C-Kit exhibited a marked increase in MCD in patients with H. pylori-mediated gastritis, intestinal metaplasia, atrophy, and gastric carcinoma. However, a significant decrease in MCD was observed on repeating endoscopy evaluations for patients after treatment.

CONCLUSION

Regions that exhibit severe inflammation, metaplasia, atrophy, and carcinoma demonstrated an increase in MCD with H. pylori-mediated gastritis. A detailed investigation in clinical practice to screen early diagnosis and treatment needs to be performed in high H. pylori prevalence.

Helicobacter pylori infection in humans and phytotherapy, probiotics, and emerging therapeutic interventions: a review

The global prevalence of Helicobacter pylori (H. pylori) infection remains high, indicating a persistent presence of this pathogenic bacterium capable of infecting humans. This review summarizes the population demographics, transmission routes, as well as conventional and novel therapeutic approaches for H. pylori infection. The prevalence of H. pylori infection exceeds 30% in numerous countries worldwide and can be transmitted through interpersonal and zoonotic routes. Cytotoxin-related gene A (CagA) and vacuolar cytotoxin A (VacA) are the main virulence factors of H. pylori, contributing to its steep global infection rate. Preventative measures should be taken from people's living habits and dietary factors to reduce H. pylori infection. Phytotherapy, probiotics therapies and some emerging therapies have emerged as alternative treatments for H. pylori infection, addressing the issue of elevated antibiotic resistance rates. Plant extracts primarily target urease activity and adhesion activity to treat H. pylori, while probiotics prevent H. pylori infection through both immune and non-immune pathways. In the future, the primary research focus will be on combining multiple treatment methods to effectively eradicate H. pylori infection.

Serum pepsinogen level as a biomarker for atrophy, reflux esophagitis, and gastric cancer screening in Indonesia

Background

Chronic dyspepsia's symptoms are frequently seen in primary to tertiary healthcare in Indonesia. This study aimed to describe the potential usability of pepsinogen (PG) values in determining gastric mucosal conditions, including superficial gastritis and atrophic gastritis.

Materials and Methods

We recruited 646 adult dyspeptic patients and then analyzed PG values (including PGI, PGII, and PGI/II ratio) with endoscopic findings, gastric mucosal damages, and Helicobacter pylori infection. The gastric mucosal damage and H. pylori infection were evaluated using histological examination based on the updated Sydney system.

Results

Among 646 enrolled patients, 308 (47.2%), 212 (32.8%), 91 (14.1%), 34 (5.2%), and 1 (0.2%) patient were diagnosed with normal mucosa, gastritis, reflux esophagitis, peptic ulcer disease, and gastric cancer, respectively. Significant differences in PGI, PGII, and PGI/II ratio values were observed among ethnic groups (all P < 0.01). The PGI and PGII levels were significantly higher and PGI/II was significantly lower in H. pylori-infected patients than in uninfected ones (all P < 0.001). The optimal cutoff value for PGII and PGI/II was 12.45 ng/mL with an area under the curve (AUC) value of 0.755 (0.702-0.811), sensitivity 59.3%, and specificity 77.1%; and 4.75 with AUC value of 0.821 (0.763-0.855), sensitivity 81.5%, and specificity 78.7%, respectively, to determine moderate-severe atrophy.

Conclusion

Serum PG levels, a useful biomarker, represent the endoscopic findings, especially for reflux esophagitis. In addition, the benefits of PG values detecting atrophic gastritis were limited to moderate-severe atrophic gastritis. This usefulness requires careful attention for several ethnic groups in Indonesia.

Stomach Cancer Screening Services of Bhutan

Stomach cancer is a common public health problem in South East Asia including Bhutan. Chronic infection with Helicobacter pylori is regarded as the principal cause of stomach cancer. Herein, we present the incidence of stomach cancer in Bhutan for eight years (from 2014 to 2021). We also discuss the steps taken for the prevention and early detection of stomach cancer.

Helicobacter pylori Infection Acts as an Independent Risk Factor for Intracranial Atherosclerosis in Women Less Than 60 Years Old

Background: Studies show inconsistent results regarding the relationship between Helicobacter pylori (H. pylori) infection and stroke. The present study assessed a potential association between H. pylori infection and an important risk factor for stroke, intracranial atherosclerosis.

Methods: In total, 15,798 subjects with transcranial Doppler (TCD) and 13C-urea breath test (13C-UBT) were enrolled from March 2012 to March 2017. Intracranial atherosclerosis was further measured using intracranial carotid artery calcification (ICAC) on past or recent head CT, and 14,084 subjects were ultimately included in the study. Baseline demographics, atherosclerosis risk factors, and laboratory results were investigated. Since endothelial dysfunction is critical to the development of atherosclerosis, the role of H. pylori in migration, tube formation, and proliferation of human brain microvascular endothelial cells (HBMECs) was assessed in vitro.

Results: The intracranial atherosclerosis group had a higher proportion of women and a greater rate of H. pylori infection than those without intracranial atherosclerosis. H. pylori infection was significantly more common in women with intracranial atherosclerosis than males. In addition, the incidence of intracranial atherosclerosis was significantly higher in women with H. pylori infection than uninfected women (53.8 vs. 46.4%, p &lt; 0.001). In an adjusted model, H. pylori was shown to be an independent risk factor for intracranial atherosclerosis in women ≤ 60 years of age [odds ratio (OR) = 2.261, 95% CI = 1.839–2.780, p &lt; 0.001]. Serum exosomes from patients with H. pylori infection had significantly reduced brain endothelial cell migration, tube formation, and proliferation in vitro.

Conclusion:Helicobacter pylori infection may be an important independent risk factor for intracranial atherosclerosis in women ≤ 60 years of age.

Overview of Helicobacter pylori Infection: Clinical Features, Treatment, and Nutritional Aspects

Helicobacter pylori (H. pylori) is a 0.5-1 µm wide, 2-4 µm long, short helical, S-shaped Gram-negative microorganism. It is mostly found in the pyloric region of the stomach and causes chronic gastric infection. It is estimated that these bacteria infect more than half of the world's population. The mode of transmission and infection of H. pylori is still not known exactly, but the faecal-oral and oral-oral routes via water or food consumption are thought to be a very common cause. In the last three decades, research interest has increased regarding the pathogenicity, microbial activity, genetic predisposition, and clinical treatments to understand the severity of gastric atrophy and gastric cancer caused by H. pylori. Studies have suggested a relationship between H. pylori infection and malabsorption of essential micronutrients, and noted that H. pylori infection may affect the prevalence of malnutrition in some risk groups. On the other hand, dietary factors may play a considerably important role in H. pylori infection, and it has been reported that an adequate and balanced diet, especially high fruit and vegetable consumption and low processed salty food consumption, has a protective effect against the outcomes of H. pylori infection. The present review provides an overview of all aspects of H. pylori infection, such as clinical features, treatment, and nutrition.

Serum Helicobacter pylori antibody reactivity in seven Asian countries using an automated latex aggregation turbidity assay

BACKGROUND AND AIM

To determine the application range of diagnostic kits utilizing anti-Helicobacter pylori antibody, we tested a newly developed latex aggregation turbidity assay (latex) and a conventional enzyme-linked immunosorbent assay (E-plate), both containing Japanese H. pylori protein lysates as antigens, using sera from seven Asian countries.

METHODS

Serum samples (1797) were obtained, and standard H. pylori infection status and atrophy status were determined by culture and histology (immunohistochemistry) using gastric biopsy samples from the same individuals. The two tests (enzyme-linked immunosorbent assay and latex) were applied, and receiver operating characteristics analysis was performed.

RESULTS

Area under the curve (AUC) from the receiver operating characteristic of E-plate and latex curves were almost the same and the highest in Vietnam. The latex AUC was slightly lower than the E-plate AUC in other countries, and the difference became statistically significant in Myanmar and then Bangladesh as the lowest. To consider past infection cases, atrophy was additionally evaluated. Most of the AUCs decreased using this atrophy-evaluated status; however, the difference between the two kits was not significant in each country, but the latex AUC was better using all samples. Practical cut-off values were 3.0 U/mL in the E-test and 3.5 U/mL in the latex test, to avoid missing gastric cancer patients to the greatest extent possible.

CONCLUSIONS

The kits were applicable in all countries, but new kits using regional H. pylori strains are recommended for Myanmar and Bangladesh. Use of a cut-off value lower than the best cut-off value is essential for screening gastric cancer patients.

Pepsinogen and Serum IgG Detection Is a Valuable Diagnostic Method for Helicobacter pylori Infection in a Low-Prevalence Country: A Report from Sri Lanka

The use of serum anti-Helicobacter pylori IgG and pepsinogen (PG) detection as a diagnostic method was evaluated in Sri Lanka. Gastric biopsies were performed (353 patients), and the prevalence of H. pylori infection was 1.7% (culture) and 2.0% (histology). IgG serology testing showed an area under the curve (AUC) of 0.922 (cut-off, 2.95 U/mL; specificity, 91.56%; sensitivity, 88.89%). Histological evaluation showed mild atrophy (34.3%), moderate atrophy (1.7%), metaplasia (1.7%), chronic gastritis (6.2%), and normal tissue (56%). The PGI/PGII ratio was significantly higher in H. pylori-negative patients (p < 0.01). PGII and PGI/PGII levels were lower in patients with metaplasia than in those with normal mucosa (p = 0.049 and p < 0.001, respectively). The PGI/PGII ratio best discriminated metaplasia and moderate atrophy (AUC 0.88 and 0.76, respectively). PGI and PGII alone showed poor discriminative ability, especially in mild atrophy (0.55 and 0.53, respectively) and chronic gastritis (0.55 and 0.53, respectively). The best cut-off to discriminate metaplasia was 3.25 U/mL (95.19% specificity, 83.33% sensitivity). Anti-H. pylori IgG and PG assessment (ABC method) was performed (group B, 2.0%; group A, 92.1%). The new cut-off more accurately identified patients with metaplasia requiring follow-up (group B, 5.4%). Assessment of anti-H. pylori IgG and PG is valuable in countries with a low prevalence of H. pylori infection.

Helicobacter pylori in the Indonesian Malay's descendants might be imported from other ethnicities

BACKGROUND

Even though the incidence of H. pylori infection among Malays in the Malay Peninsula is low, we observed a high H. pylori prevalence in Sumatra, which is the main residence of Indonesian Malays. H. pylori prevalence among Indonesian Malay descendants was investigated.

RESULTS

Using a combination of five tests, 232 recruited participants were tested for H- pylori and participants were considered positive if at least one test positive. The results showed that the overall H. pylori prevalence was 17.2%. Participants were then categorized into Malay (Aceh, Malay, and Minang), Java (Javanese and Sundanese), Nias, and Bataknese groups. The prevalence of H. pylori was very low among the Malay group (2.8%) and no H. pylori was observed among the Aceh. Similarly, no H. pylori was observed among the Java group. However, the prevalence of H. pylori was high among the Bataknese (52.2%) and moderate among the Nias (6.1%). Multilocus sequence typing showed that H. pylori in Indonesian Malays classified as hpEastAsia with a subpopulation of hspMaori, suggesting that the isolated H. pylori were not a specific Malays H. pylori.

CONCLUSIONS

Even though the ethnic groups live together as a community, we observed an extremely low H. pylori infection rate among Indonesian Malay descendants with no specific Indonesian Malay H. pylori. The results suggest that H. pylori was not originally among these groups and H. pylori was imported from other ethnic groups.

Zerumbone Inhibits Helicobacter pylori Urease Activity

Helicobacter pylori (H. pylori) produces urease in order to improve its settlement and growth in the human gastric epithelium. Urease inhibitors likely represent potentially powerful therapeutics for treating H. pylori; however, their instability and toxicity have proven problematic in human clinical trials. In this study, we investigate the ability of a natural compound extracted from Zingiber zerumbet Smith, zerumbone, to inhibit the urease activity of H. pylori by formation of urease dimers, trimers, or tetramers. As an oxygen atom possesses stronger electronegativity than the first carbon atom bonded to it, in the zerumbone structure, the neighboring second carbon atom shows a relatively negative charge (δ⁻) and the next carbon atom shows a positive charge (δ⁺), sequentially. Due to this electrical gradient, it is possible that H. pylori urease with its negative charges (such as thiol radicals) might bind to the β-position carbon of zerumbone. Our results show that zerumbone dimerized, trimerized, or tetramerized with both H. pylori urease A and urease B molecules, and that this formation of complex inhibited H. pylori urease activity. Although zerumbone did not affect either gene transcription or the protein expression of urease A and urease B, our study demonstrated that zerumbone could effectively dimerize with both urease molecules and caused significant functional inhibition of urease activity. In short, our findings suggest that zerumbone may be an effective H. pylori urease inhibitor that may be suitable for therapeutic use in humans.

Epidemiological Profile of Helicobacter pylori Infection in Patients with Digestive Symptoms in Algeria

BACKGROUND

The purpose of this study was to assess the prevalence of Helicobacter pylori infection in Algerian patients with peptic disorders and evaluate the impact of different epidemiological factors (age, sex, sampling site, presence or absence of H. pylori, and type of pathology related to this bacterium).

METHODS

We undertook a retrospective and descriptive study on a series of 735 symptomatic patients identified in the laboratory of pathological anatomy at Hassani Abdelkader University Hospital Center of Sidi Bel Abbes, Algeria, over a period of 16 years from January 2002 to December 2017. All patients had benefited from a high gastroscopic fibroscopy and the diagnosis was made by histological examination (hematoxylin-eosin staining). The epidemiological factors, as well as the main gastric diseases related to this bacterium, were studied.

RESULTS

The prevalence of H. pylori infection was 66.12%. The infection was more important in the age group 60-69 years (71.43%). The prevalence of H. pylori infection was statistically higher in women than in men (69.3% vs. 60.7%, p < 0.01).The antral region was most colonized by H. pylori (71.73%). In addition, the infection was associated mainly with atrophic gastritis (69.65%).

CONCLUSION

In this context, the identification of epidemiological data would be of great value in guiding strategies to control the spread of this bacterium.

Gastric microbiota and Helicobacter pylori in Indonesian population

BACKGROUND

The profile of gastric mucosal microbiota has not yet been described in the Indonesian population where the prevalence of Helicobacter pylori is low.

METHODS

This is a cross-sectional study analyzing 16S rRNA of 137 gastric biopsy specimens. We analyzed the association between gastric microbiota, H. pylori infection, and gastric mucosal damage.

RESULT

Among 137 analyzed samples, 27 were H. pylori-positive and 110 were H. pylori -negative based on culture, histology, and 16S rRNA gene analysis. Significantly lower α-diversity parameters, including Pielou's index, was observed in H. pylori-infected individuals compared with noninfected individuals (all P < .001). Among H. pylori-negative individuals, the permutational analysis of variance of Bray-Curtis dissimilarity distances showed a significant association with different ethnicities, suggesting some ethnic groups had specific microbiota profiles based on the presence of different operational taxonomic units. The linear discriminant analysis effect size (LEfSe) of the H. pylori-negative group showed significant associations between the presence of Micrococcus luteus and Sphingomonas yabuuchiae with Timor and Papuan ethnicities, respectively. The presence of Bulledia sp and Atopobium sp was associated with the Javanese ethnicity. We observed lower α-diversity scores in individuals with gastric mucosal damage and profiles with high abundances of Paludibacter sp and Dialister sp based on LEfSe analysis.

CONCLUSION

Our findings suggest the presence of H. pylori is more correlated with a distinct microbiome profile than ethnic precedence.

Population-based study of Helicobacter pylori infection and antibiotic resistance in Bhutan

OBJECTIVES

Bhutan suffers from a high prevalence of Helicobacter pylori (H. pylori) infection and gastric cancer-related mortality. In preparation for a countrywide H. pylori eradication program, the antibiotic resistance patterns of H. pylori infection were surveyed in different geographical regions.

METHODS

Dyspeptic patients in 6 districts including Thimphu, Punakha, Wangdue, Trongsa, Bumthang, and Haa underwent upper gastrointestinal endoscopy during GASTROCAMP and were enrolled between December 2010 and April 2015. Gastric biopsies were obtained for rapid urease test, histopathology, and H. pylori culture. Antimicrobial susceptibility testing was later performed if the culture was positive.

RESULTS

A total of 1178 patients were surveyed. The overall H. pylori infection in Bhutan was 66.2%. Punakha had the highest prevalence of H. pylori infection (85.6%). Thimphu and Punakha (city areas) had higher prevalence of H. pylori infection than rural districts (73.5% vs 63.3%, OR=1.61, 95% CI 1.22-2.13, p=0.0008). There were 357 patients (30.3%) with positive H. pylori culture completed antimicrobial susceptibility testing. The mean age was 40.5 years with female predominance (57.1%). No amoxicillin resistant strains were found. Metronidazole resistance was 81% followed by levofloxacin resistance (8.1%). Clarithromycin (2%) and tetracycline (0.6%) resistance was rare except in Thimphu, the capital city (10%) vs 0% in rural areas, p<0.001. The metronidazole resistance rate remained stable at approximately 80% during the past 5 years of study. Levofloxacin-resistant strains gradually rose from 5.3% in 2010 to 9.9% in 2015.

CONCLUSIONS

Bhutan had a high prevalence of H. pylori infection. Metronidazole resistance was extremely high, whereas clarithromycin resistance was quite low in this specific area. Antibiotic resistance pattern could be good evidence for guiding a proper treatment regimen for H. pylori infection in Bhutan.

Serum pepsinogens as a gastric cancer and gastritis biomarker in South and Southeast Asian populations

Serum pepsinogens have been widely acknowledged as gastric mucosal biomarkers; however, a multicountry report on the benefits of pepsinogens as biomarkers has not yet been published. We analyzed 1,206 sera and gastric mucosal samples collected from Bangladesh, Bhutan, Indonesia, Myanmar, Nepal and Thailand then assessed the association between gastric mucosal changes and Helicobacter pylori infection. The new cutoff values for serum pepsinogen values were evaluated using a receiver operating characteristic analysis. The participants with H. pylori infection had significantly lower pepsinogen I and higher pepsinogen II values, but a lower pepsinogen I/II ratio than participants without the infection (all P < .001). The pepsinogen I and pepsinogen I/II values were significantly higher and lower, respectively, in individuals with atrophic gastritis than in those without (both P < .001). Among uninfected individuals, only the pepsinogen I/II ratio was significantly lower in atrophic individuals. Pepsinogen I/II ratio also were significantly different between disease among H. pylori-positive and H. pylori-negative individuals, suggesting the pepsinogen I/II ratio is a robust biomarker for determining both chronic and atrophic gastritis. The cutoffs for detecting chronic and atrophic gastritis for the pepsinogen I/II ratio were 4.65 and 4.95, respectively. In conclusion, pepsinogen levels are useful biomarker for both chronic gastritis and atrophic gastritis, but they should be used with caution. Population-based validation is necessary to determine the best cutoff values. Among all pepsinogen values, the pepsinogen I/II ratio was the most reliable gastric mucosal-change biomarker.

Efficacy of Omeprazole, Tetracycline, and 4 Times Daily Dosing of Amoxicillin in Helicobacter pylori Eradication in Limited Resource Area in Bhutan: A Prospective Randomized Trial (BHUTAN Study)

Backgrourd:

H. pylori-associated gastric cancer is the first cancer-related death in Bhutan. Effective regimen for H. pylori eradication is essential to reduce risk of developing gastric cancer. Clarithromycin is not widely used in this limited resource country. Aim of this study was to evaluate proper regimen and prevalence of antibiotic resistance pattern for H. pylori eradication in Bhutan.

Methods:

Five hundred and forty-six patients underwent gastroscopy during GASTROCAMP between October 2014 and April 2015 in Bhutan and 77 patients were enrolled. Four gastric biopsies were obtained for rapid urease test, histopathology, H. pylori culture with Epsilometer test. All H. pylori-positive patients were randomized to receive either 7-day or 14-day of 500 mg amoxicillin four times daily, 500 mg tetracycline four times daily, and 20 mg omeprazole twice daily.

Results:

Seventy-seven subjects were enrolled (54 females, 23 males, mean age = 45.4 years). Of 77 patients, 52 (67.5%) received 7-day regimen while 25 (32.5%) had 14-day regimen. Prevalence of H. pylori was 38.2%. Antibiotic resistance was 80.0% for metronidazole, 11.1% for levofloxacin and no resistance seen in amoxicillin, tetracycline and clarithromycin. Overall eradication rates of 7-day and 14-day regimens were 51.9% and 80.0%, p = 0.02. Female and age ≥40 years had significantly higher eradication rate when receiving 14-day compared to 7-day regimen (94.1% vs. 45.9%, OR = 18.82; 95% CI 2.26-157.02, p = 0.0007 and 86.7% vs. 50.0%, OR = 6.50; 95% CI 1.25-33.91, p = 0.02, respectively).

Conclusions:

Fourteen-day regimen might be an acceptable regimen for H. pylori eradication in limited resource area such as Bhutan. Female and age ≥40 years should receive longer duration of treatment. This 14-day regimen could at least reduce the risk of developing H. pylori-associated diseases especially peptic ulcer with complications and gastric cancer which lead to many deaths in Bhutan.

Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

Analysis of risks of gastric cancer by gastric mucosa among Indonesian ethnic groups

Indonesia is a big country with multiethnic populations whose gastric cancer risks have not been elucidated. We performed a nationwide survey and obtained histological specimens from 1053 individuals in 19 cities across the country. We examined the gastric mucosa, the topography, the atrophic gastritis risk factors, and the gastric cancer risk scores. Almost half (46.1%) of the patients with dyspeptic symptoms had histological abnormalities; chronic (36.3%) and atrophic gastritis (28.9%) being the most frequent. Individuals of the Timor ethnicity had the highest prevalence of acute (52.6%) and chronic gastritis (68.4%), even those negative for H. pylori. Our topographic analysis showed the majority of patients had predominantly antral acute and chronic gastritis. A multivariate logistic regression model showed age (Odds ratio [OR], 1.107), Timor ethnicity (OR, 8.531), and H. pylori infection (OR, 22.643) as independent risk factors for presence of atrophic gastritis. In addition, the gastric cancer risk score was highest in those from Timor, Papuan, and Bugis ethnic populations. Overall, Indonesia is a low-risk gastric cancer country. However, several ethnic groups displayed severe gastric mucosa symptoms suggesting policy makers should focus on those ethnic groups to perform gastric cancer screenings and to eradicate H. pylori.

Effective therapeutic regimens in two South Asian countries with high resistance to major Helicobacter pylori antibiotics

Background

Nepal and Bangladesh have a high prevalence of Helicobacter pylori with high resistance rates to clarithromycin, metronidazole, and levofloxacin. Here, we evaluated the susceptibility and genetic mutations of 5 alternative antibiotics against isolates from both countries to obtain an effective treatment regimen for H. pylori eradication.

Methods

We used the agar dilution method to determine the minimal inhibitory concentration of 5 alternative antibiotics against 42 strains from Nepal and 56 from Bangladesh and performed whole genome mutation analysis.

Results

No resistance to furazolidone or rifabutin and a high susceptibility of sitafloxacin (95.2% in Nepal and 98.2% in Bangladesh) were observed. In contrast, resistance to rifaximin (52.4% in Nepal and 64.3% in Bangladesh) was high. Moreover, resistance to garenoxacin was higher in Bangladesh (51.6%) than in Nepal (28.6%, P = 0.041), most likely due to its correlation with levofloxacin resistance (P = 0.03). Garenoxacin and rifaximin were significantly correlated in Bangladesh (P = 0.014) and occurred together with all sitafloxacin-resistant strains. Mutations of gyrA could play a significant role in garenoxacin resistance, and double mutations of A87 and D91 were associated with sitafloxacin resistance. Analysis of the rpoB gene demonstrated well-known mutations, such as V657I, and several novel mutations, including I2619V, V2592 L, T2537A, and F2538 L.

Conclusions

Rifabutin can be cautiously implemented as therapy for H. pylori infection due to its interaction with the tuberculosis endemic in Bangladesh. The high susceptibility of furazolidone and sitafloxacin suggests their possible future application in Nepal and Bangladesh.

Helicobacter pylori bab characterization in clinical isolates from Bhutan, Myanmar, Nepal and Bangladesh

BACKGROUND

Helicobacter pylori BabA is an important outer membrane protein that involves in the attachment to the gastric mucosa and enhances the virulence property of the bacterium. This study was aimed to characterize the bab genotypes, to evaluate its association with cagA, vacA and clinical diseases as well as degree of gastric inflammation.

METHODS

H. pylori isolates from four countries were subjected for the characterization of bab. The locus specific forward and bab specific reverse primers were used to get the specific products by PCR, which could distinguish the three locus (A, B and C). The histological activities were evaluated according to the Updated Sydney system.

RESULT

In patients from high risk countries (Bhutan and Myanmar) relatively higher frequencies of strains with babA-positivity (91.8% and 90.7%, respectively), babA at locus A (98% and 91.2%, respectively) and with single babA (96.8% and 91.2%, respectively) were found. Strains with two loci occupied were the most prevalent in Bhutan (84.6%), Myanmar (74.7%), Nepal (58.3%) and Bangladesh (56.9%). The genotype babA at locus A/babB at locus B/bab-negative at locus C (babA/babB/-) was the most common genotype isolated from Bhutan (82.7%), Myanmar (58.7%), Nepal (32%) and Bangladesh (31.4%) among all genotypes assessed. This genotype was also associated with the peptic ulcer disease (P = 0.013) when compared to gastritis. babA-positive characteristics and the genotype babA/babB/- exhibited the enhanced histological activities.

CONCLUSIONS

The higher prevalence of virulence associated babA-positive characteristics and enhanced histological activities in Bhutan than in Myanmar, Nepal and Bangladesh might partly explain why the peoples in Bhutan are at higher risk for developing severe gastric complications.

Prevalence, risk factors, and virulence genes of Helicobacter pylori among dyspeptic patients in two different gastric cancer risk regions of Thailand

Gastric cancer risk is varied among different regions of Thailand. We examined the characteristics of Helicobacter pylori infection in two regions of Thailand. The H. pylori status of 273 dyspeptic patients (136 from the South and 137 from the North; a low and high incidence of gastric cancer region, respectively) was evaluated, and virulence genotypes (cagA, vacA, hrgA and jhp0562-positive/β-(1,3)galT) were determined. The overall H. pylori infection rate was 34.1% (93/273). The prevalence was higher in the North than in the South (50.4% vs. 17.6%, P <0.001) and was significantly higher among individuals with the following characteristics: low income, birthplace in the Northeast or North regions, agricultural employment, or consumption of alcohol or unboiling water. Among these socio-demographic determinants, region was an independent risk factor for H. pylori infection (odds ratio = 6.37). Patients including both H. pylori infected and uninfected cases who lived in the North had significantly more severe histological scores than those in the South. In contrast, among H. pylori-positive cases, patients in the South had significantly more severe histological scores than those in the North. Of the 74 strains cultured, 56.8% carried Western-type cagA, with a higher proportion in the South than in the North (76.2% vs. 49.1%, P = 0.05). In disagreement with the current consensus, patients infected with the Western-type cagA strains had more severe inflammation scores in the antrum than those infected with the East Asian-type cagA strains (P = 0.027). Moreover, Western-type cagA strains induced more severe histological scores in patients from the South than those of either genotype from the North. Other virulence genes had no influence on histological scores. The incidence of gastric cancer in Thailand was different among regions and corresponded to differences in the prevalence of H. pylori infection. More careful follow-up for patients in the South will be required, even if they are infected with H. pylori carrying Western-type cagA.

Two populations of less-virulent Helicobacter pylori genotypes in Bangladesh

Bangladesh has a population with a low gastric cancer risk but high prevalence of Helicobacter pylori infection. Several studies have examined virulence genes in H. pylori from Bangladesh. We analyzed cagA and vacA subtypes and their association with severe histology phenotypes, and analyzed population types among Bangladeshi strains. We included patients who underwent endoscopy in Dhaka. Sequences of virulence genes and seven housekeeping genes were obtained by next generation sequencing and confirmed by Sanger sequencing. We isolated 56 H. pylori strains from 133 patients, of which 73.2% carried cagA, and all were considered Western-type. Patients infected with cagA-positive strains had more severe histological scores than patients infected with cagA-negative strains. Among vacA s1 and m1 genotypes, the s1a (97.8%, 43/44) and m1c (28/30, 93.3%) genotypes were predominant. All strains containing s1 and m1 (30/56, 53.6%) also had i1, d1, and c1. In contrast, all strains containing the less-virulent genotypes s2 and m2 (12/56, 21.4%) also possessed i2, d2, and c2. Multivariate analysis indicated that subjects infected with vacA m1-genotype strains only had a significantly higher risk of antrum atrophy than patients infected with m2-genotype strains. Of the two main H. pylori populations in this study, hpAsia2 strains were associated with higher activity and inflammation in the antrum compared to hpEurope strains; however, only vacA s1m1i1d1c1 strains, independent of population type, were significantly associated with inflammation in the antrum, unlike the s2m2i2d2c2 genotype. In conclusion, Bangladeshi strains were divided into two main populations of different genotypes. The low incidence of gastric cancer in Bangladesh might be attributable to the high proportion of less-virulent genotypes, which may be a better predictor of gastric cancer risk than the ancestral origin of the H. pylori strains. Finally, the vacA m region may be a better virulence marker than other regions.

Autophagy-related genes in Helicobacter pylori infection

BACKGROUND

In vitro studies have shown that Helicobacter pylori (H. pylori) infection induces autophagy in gastric epithelial cells. However, prolonged exposure to H. pylori reduces autophagy by preventing maturation of the autolysosome. The alterations of the autophagy-related genes in H. pylori infection are not yet fully understood.

MATERIALS AND METHODS

We analyzed autophagy-related gene expression in H. pylori-infected gastric mucosa compared with uninfected gastric mucosa obtained from 136 Bhutanese volunteers with mild dyspeptic symptoms. We also studied single nucleotide polymorphisms (SNPs) of autophagy-related gene in 283 Bhutanese participants to identify the influence on susceptibility to H. pylori infection.

RESULTS

Microarray analysis of 226 autophagy-related genes showed that 16 genes were upregulated (7%) and nine were downregulated (4%). We used quantitative reverse transcriptase polymerase chain reaction to measure mRNA levels of the downregulated genes (ATG16L1, ATG5, ATG4D, and ATG9A) that were core molecules of autophagy. ATG16L1 and ATG5 mRNA levels in H. pylori-positive specimens (n=86) were significantly less than those in H. pylori-negative specimens (n=50). ATG16L1 mRNA levels were inversely related to H. pylori density. We also compared SNPs of ATG16L1 (rs2241880) among 206 H. pylori-positive and 77 H. pylori-negative subjects. The odds ratio for the presence of H. pylori in the GG genotype was 0.40 (95% CI: 0.18-0.91) relative to the AA/AG genotypes.

CONCLUSIONS

Autophagy-related gene expression profiling using high-throughput microarray analysis indicated that downregulation of core autophagy machinery genes may depress autophagy functions and possibly provide a better intracellular habit for H. pylori in gastric epithelial cells.

Gastric mucosal status in populations with a low prevalence of Helicobacter pylori in Indonesia

In Indonesia, endoscopy services are limited and studies about gastric mucosal status by using pepsinogens (PGs) are rare. We measured PG levels, and calculated the best cutoff and predictive values for discriminating gastric mucosal status among ethnic groups in Indonesia. We collected gastric biopsy specimens and sera from 233 patients with dyspepsia living in three Indonesian islands. When ≥5.5 U/mL was used as the best cutoff value of Helicobacter pylori antibody titer, 8.6% (20 of 233) were positive for H. pylori infection. PG I and II levels were higher among smokers, and PG I was higher in alcohol drinkers than in their counterparts. PG II level was significantly higher, whereas PG I/II ratios were lower in H. pylori-positive than in H. pylori-negative patients. PG I/II ratios showed a significant inverse correlation with the inflammation and atrophy scores of the antrum. The best cutoff values of PG I/II were 4.05 and 3.55 for discriminating chronic and atrophic gastritis, respectively. PG I, PG II, and PG I/II ratios were significantly lower in subjects from Bangli than in those from Makassar and Surabaya, and concordant with the ABC group distribution; however, group D (H. pylori negative/PG positive) was the lowest in subjects from Bangli. In conclusion, validation of indirect methods is necessary before their application. We confirmed that serum PG level is a useful biomarker determining chronic gastritis, but a modest sensitivity for atrophic gastritis in Indonesia. The ABC method should be used with caution in areas with a low prevalence of H. pylori.

Helicobacter pylori in bottled mineral water: genotyping and antimicrobial resistance properties

BACKGROUND

Up to now, fecal-oral and oral-oral are the most commonly known routes for transmission of H. pylori, therefore, contaminated water can play an important role in transmission of H. pylori to humans. Genotyping using virulence markers of H. pylori is one of the best approaches to study the correlations between H. pylori isolates from different samples. The present research was carried out to study the vacA, cagA, cagE, oipA, iceA and babA2 genotyping and antimicrobial resistance properties of H. pylori isolated from the bottled mineral water samples of Iran.

RESULTS

Of 450 samples studied, 8 samples (1.77%) were contaminated with H. pylori. Brand C of bottled mineral water had the highest prevalence of H. pylori (3.63%). The bottled mineral water samples of July month had the highest levels of H. pylori-contamination (50%). H. pylori strains had the highest levels of resistance against metronidazole (62.5%), erythromycin (62.5%), clarithromycin (62.5%), amoxicillin (62.5%) and trimethoprim (62.5%). Totally, 12.5% of strains were resistant to more than 6 antibiotics. VvacAs1a (100%), vacAm1a (87.5%), cagA (62.5%), iceA1 (62.5%), oipA (25%), babA2 (25%) and cagE (37.5%) were the most commonly detected genotypes. M1as1a (62.5%), m1as2 (37.5%), m2s2 (37.5%) and S1a/cagA+/IceA2/oipA-/babA2-/cagE- (50%) were the most commonly detected combined genotypes.

CONCLUSIONS

Contaminated bottled mineral water maybe the sources of virulent and resistant strains H. pylori. Careful monitoring of bottled mineral water production may reduce the risk of H. pylori transmission into the human population.

Rare Helicobacter pylori Virulence Genotypes in Bhutan

Both the prevalence of Helicobacter pylori infection and the incidence of gastric cancer are high in Bhutan. The high incidence of atrophic gastritis and gastric cancer suggest the phylogeographic origin of an infection with a more virulent strain of H. pylori. More than 90% of Bhutanese strains possessed the highly virulent East Asian-type CagA and all strains had the most virulent type of vacA (s1 type). More than half also had multiple repeats in East Asian-type CagA, which are rare in other countries and are reported characteristictly found in assciation with atrophic gastritis and gastric cancer consistent with Bhutanese strains having multiple H. pylori virulence factors associated with an increase in gastric cancer risk. Phylogeographic analyses showed that most Bhutanese strains belonged to the East Asian population type with some strains (17.5%) sharing East Asian and Amerindian components. Only 9.5% belonged to the European type consistant with H. pylori in Bhutan representing an intermediate evolutionary stage between H. pylori from European and East Asian countries.

Diagnostic Methods of Helicobacter pylori Infection for Epidemiological Studies: Critical Importance of Indirect Test Validation

Among the methods developed to detect H. pylori infection, determining the gold standard remains debatable, especially for epidemiological studies. Due to the decreasing sensitivity of direct diagnostic tests (histopathology and/or immunohistochemistry [IHC], rapid urease test [RUT], and culture), several indirect tests, including antibody-based tests (serology and urine test), urea breath test (UBT), and stool antigen test (SAT) have been developed to diagnose H. pylori infection. Among the indirect tests, UBT and SAT became the best methods to determine active infection. While antibody-based tests, especially serology, are widely available and relatively sensitive, their specificity is low. Guidelines indicated that no single test can be considered as the gold standard for the diagnosis of H. pylori infection and that one should consider the method's advantages and disadvantages. Based on four epidemiological studies, culture and RUT present a sensitivity of 74.2–90.8% and 83.3–86.9% and a specificity of 97.7–98.8% and 95.1–97.2%, respectively, when using IHC as a gold standard. The sensitivity of serology is quite high, but that of the urine test was lower compared with that of the other methods. Thus, indirect test validation is important although some commercial kits propose universal cut-off values.

Prostate stem cell antigen gene TT genotype and development of intestinal metaplasia in Helicobacter pylori infection

OBJECTIVES

Gastric cancer is etiologically related to interactions between Helicobacter pylori (H. pylori) infection, environmental and host factors. Gastric carcinoma is associated with a cascade of increasing atrophic gastric mucosal damage. Prostate stem cell antigen (PSCA) polymorphisms have been associated with an increased risk of gastric cancer. We aimed to examine the interaction between PSCA polymorphisms and H. pylori in the progression of H. pylori-related gastritis.

METHODS

The genotypes (TT, TC and CC) of PSCA single nucleotide polymorphism rs2294008 among H. pylori infected and uninfected Bhutanese were compared with the severity of H. pylori-related gastritis [neutrophils, monocytes, atrophy scores, H. pylori density, and the presence and extent of intestinal metaplasia (IM)] using the updated Sydney system.

RESULTS

Biopsies from 339 participants were included. The proportion of biopsies with IM was significantly (P < 0.05) greater in those with the TT genotype than in either those with the CT or CC genotype. Although no significant differences were found in inflammation or H. pylori density scores, the scores for IM at both gastric corpus and antrum among participants infected by H. pylori with the TT genotype was significantly (P < 0.05) greater than in the C allele carriers.

CONCLUSION

PSCA TT genotype is associated with a more than a threefold increase in the prevalence and the extent of gastric mucosal IM compared to C allele carriers among H. pylori-infected Bhutanese.

Validation of Urine Test for Detection of Helicobacter pylori Infection in Indonesian Population

We measured the accuracy of the urine test (RAPIRUN) for detection of Helicobacter pylori infection in Indonesia (Jakarta, Pontianak, and Jayapura) using histology confirmed by immunohistochemistry and/or culture as gold standards. We also used immunohistochemistry to identify CagA phenotype and analyzed H. pylori CagA diversity in Indonesia. The overall prevalence of H. pylori infection in 88 consecutive dyspeptic patients based on the urine test was 15.9% (14/88), 38.1% for patients in Jayapura that had higher prevalence of H. pylori infection than that in Jakarta (9.7%, P = 0.02) and Pontianak (8.3%, P = 0.006). Overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of RAPIRUN were 83.3%, 94.7%, 71.4%, 97.3%, and 93.2%, respectively. All of the H. pylori-positive patients were immunoreactive for anti-CagA antibody but not immunoreactive for East Asian specific anti-CagA antibody in all H. pylori-positive subjects. We confirmed the high accuracy of RAPIRUN in Indonesian population. In general, we found less virulent type of H. pylori in Indonesia, which partly explained the low incidence gastric cancer in Indonesia.

On the importance of developing a new generation of breath tests for Helicobacter pylori detection

State-of-the-art methods for non-invasive detection of the Helicobacter pylori (H. pylori) infection have been considered. A reported global tendency towards a non-decreasing prevalence of H. pylori worldwide could be co-influenced by the functional limitations of urea breath tests (UBTs), currently preferred for the non-invasive recognition of H. pylori in a clinical setting. Namely, the UBTs can demonstrate false-positive or false-negative results. Within this context, limitations of conventional clinically exploited H. pylori tests have been discussed to justify the existing need for the development of a new generation of breath tests for the detection of H. pylori and the differentiation of pathogenic and non-pathogenic strains of the bacterium. This paper presents the results of a pilot clinical study aimed at evaluating the development and diagnostic potential of a new method based on the detection of the non-urease products of H. pylori vital activity in exhaled gas. The characteristics of breath of adolescents with H. pylori-positive and H. pylori-negative functional dyspepsia, together with a consideration of the cytotoxin-associated gene A (CagA) status of H. pylori-positive subjects, have been determined for the first time using innovative point-contact nanosensor devices based on salts of the organic conductor tetracyanoquinodimethane (TCNQ). The clinical and diagnostic relevance of the response curves of the point-contact sensors was assessed. It was found that the recovery time of the point-contact sensors has a diagnostic value for differentiation of the H. pylori-associated peptic ulcer disease. The diagnostically significant elongation of the recovery time was even more pronounced in patients infected with CagA-positive H. pylori strains compared to the CagA-negative patients. Taking into account the operation of the point-contact sensors in the real-time mode, the obtained results are essential prerequisites for the development of a fast and portable breath test for non-invasive detection of cytotoxic CagA strains of H. pylori infection. The relaxation time of the point-contact nanosensors could be selected as a diagnostic criterion for non-invasive determination of H. pylori-associated destructive lesions of the gastroduodenal area in adolescents, using the point-contact spectroscopic concept of breath analysis. This can subsequently be implemented into a 'test-and-treat' approach for the management of uninvestigated dyspepsia in populations with a high prevalence of H. pylori (according to the Maastricht III and IV Consensus recommendations).

Risk Factors and Prevalence of Helicobacter pylori in Five Largest Islands of Indonesia: A Preliminary Study

The prevalence of Helicobacter pylori infection in Indonesia is still controversial and mainly investigated in the largest ethnic group, Javanese. We examined the prevalence of H. pylori infection using four different tests including culture, histology confirmed by immunohistochemistry and rapid urease test. We also analyzed risk factors associated with H. pylori infection in five largest islands in Indonesia. From January 2014–February 2015 we consecutively recruited a total of 267 patients with dyspeptic symptoms in Java, Papua, Sulawesi, Borneo and Sumatera Island. Overall, the prevalence of H. pylori infection was 22.1% (59/267). Papuan, Batak and Buginese ethnics had higher risk for H. pylori infection than Javanese, Dayak and Chinese ethnics (OR = 30.57, 6.31, 4.95; OR = 28.39, 5.81, 4.61 and OR = 23.23, 4.76, 3.77, respectively, P <0.05). The sensitivity and specificity for RUT and culture were 90.2%, 92.9% and 80.5%, 98.2%, respectively. The patients aged 50–59 years group had significantly higher H. pylori infection than 30–39 years group (OR 2.98, P = 0.05). Protestant had significantly higher H. pylori infection rate than that among Catholic (OR 4.42, P = 0.008). It was also significantly lower among peoples who used tap water as source of drinking water than from Wells/river (OR 9.67, P = 0.03). However only ethnics as become independent risk factors for H. pylori infection. Although we confirmed low prevalence of H. pylori in Javanese; predominant ethnic in Indonesia, several ethnic groups had higher risk of H. pylori infection. The age, religion and water source may implicate as a risk factor for H. pylori infection in Indonesia.

Helicobacter pylori Infection in Rural and Urban Dyspeptic Patients from Venezuela

The goal of this work was to assess the Helicobacter pylori prevalence in a rural mestizo population and compare it to an urban population from Venezuela. The study was performed in gastric juice samples of 71 dyspeptic patients from Caracas (urban) and 39 from Tucupita (rural), in the Orinoco Delta region. Helicobacter pylori was detected by amplification of 16S rRNA, glmM, and ureA genes in 55.0% patients from urban and 87.2% from rural populations. cagA was found positive in 51% and 62% urban and rural patients, respectively. Non-H. pylori Helicobacter species were not detected in the urban population, but was found in 7.7% of patients in the rural study site. Frequency values of the 16S rRNA, glmM, and ureA genes were higher in the rural population. The odds ratio for each gene was 15.18 for 16S rRNA, 2.34 for glmM, 2.89 for ureA, and 1.53 cagA, showing significant differences except for cagA when gene frequency was compared in both populations. These results demonstrate a higher frequency of H. pylori and gastric non-H. pylori Helicobacter infection in a rural mestizo population with low hygienic standards as compared with city dwellers, representing a potential risk for the development of gastroduodenal diseases.

Helicobacter pylori Infection in Thailand: A Nationwide Study of the CagA Phenotype

Background

The risk to develop gastric cancer in Thailand is relatively low among Asian countries. In addition, the age-standardized incidence rate (ASR) of gastric cancer in Thailand varies with geographical distribution; the ASR in the North region is 3.5 times higher than that in the South region. We hypothesized that the prevalence of H. pylori infection and diversity of CagA phenotype contributes to the variety of gastric cancer risk in various regions of Thailand.

Methods

We conducted a nationwide survey within Thailand. We determined H. pylori infection prevalence by detecting H. pylori, using histochemical and immunohistochemical methods. The anti-CagA antibody and anti-East-Asian type CagA antibody (α-EAS Ab), which showed high accuracy in several East Asian countries, were used to determine CagA phenotype.

Results

Among 1,546 patients from four regions, including 17 provinces, the overall prevalence of H. pylori infection was 45.9% (710/1,546). Mirroring the prevalence of H. pylori infection, histological scores were the lowest in the South region. Of the 710 H. pylori-positive patients, 93.2% (662) were immunoreactive with the anti-CagA antibody. CagA-negative strain prevalence in the South region was significantly higher than that in other regions (17.9%; 5/28; p < 0.05). Overall, only 77 patients (11.6%) were immunoreactive with the α-EAS Ab. There were no differences in the α-EAS Ab immunoreactive rate across geographical regions.

Conclusions

This is the first study using immunohistochemistry to confirm H. pylori infections across different regions in Thailand. The prevalence of East-Asian type CagA H. pylori in Thailand was low. The low incidence of gastric cancer in Thailand may be attributed to the low prevalence of precancerous lesions. The low incidence of gastric cancer in the South region might be associated with the lower prevalence of H. pylori infection, precancerous lesions, and CagA-positive H. pylori strains, compared with that in the other regions.

Molecular Epidemiology of Helicobacter pylori Infection in Nepal: Specific Ancestor Root

Prevalence of Helicobacter pylori infection in Nepal, a low-risk country for gastric cancer, is debatable. To our knowledge, no studies have examined H. pylori virulence factors in Nepal. We determined the prevalence of H. pylori infection by using three different tests, and the genotypes of virulence factors were determined by PCR followed by sequencing. Multilocus sequence typing was used to analyze the population structure of the Nepalese strains. The prevalence of H. pylori infection in dyspeptic patients was 38.4% (56/146), and was significantly related with source of drinking water. In total, 51 strains were isolated and all were cagA-positive. Western-type-cagA (94.1%), cagA pre-EPIYA type with no deletion (92.2%), vacA s1a (74.5%), and m1c (54.9%) were the predominant genotypes. Antral mucosal atrophy levels were significantly higher in patients infected with vacA s1 than in those infected with s2 genotypes (P = 0.03). Several Nepalese strains were H. pylori recombinants with genetic features of South Asian and East Asian genotypes. These included all East-Asian-type-cagA strains, with significantly lesser activity and inflammation in the corpus than the strains of the specific South Asian genotype (P = 0.03 and P = 0.005, respectively). Although the population structure confirmed that most Nepalese strains belonged to the hpAsia2 population, some strains shared hpEurope- and Nepalese-specific components. Nepalese patients infected with strains belonging to hpEurope showed higher inflammation in the antrum than strains from the Nepalese specific population (P = 0.05). These results support that ancestor roots of Kathmandu`s people not only connected with India alone.

Biomarkers for Helicobacter pylori infection and gastroduodenal diseases

Helicobacter pylori infection is a major cause of gastric cancer. Although identifying H. pylori infected subjects is the first approach for delineating the high-risk population for gastric cancer, the presence of H. pylori antibodies is not sufficient for gastric cancer screening. Among H. pylori infected subjects, only a minority of infected individuals develop gastric cancer. Serologic markers of H. pylori infection can serve as potential predictors for the development of gastric cancer. Serum or urinary H. pylori antibodies, cytotoxin-associated gene A antibodies, pepsinogen and microRNAs were reported to be associated with precancerous lesions or gastric cancer. In this review, we summarized the utilities and limitations of each strategy.

RAD51 G135C genetic polymorphism and their potential role in gastric cancer induced by Helicobacter pylori infection in Bhutan

In order to evaluate the role of the RAD51 G135C genetic polymorphism on the risk of gastric cancer induced by Helicobacter pylori infection, we determined allele frequency and genotype distribution of this polymorphism in Bhutan--a population documented with high prevalence of gastric cancer and extremely high prevalence of H. pylori infection. The status of RAD51 G135C was examined by restriction fragment length polymorphism analysis of PCR amplified fragments and sequencing. Histological scores were evaluated according to the updated Sydney system. G135C carriers showed significantly higher scores for intestinal metaplasia in the antrum than G135G carriers [mean (median) 0·33 (0) vs. 0·08 (0), P = 0·008]. Higher scores for intestinal metaplasia of G135C carriers compared to those of G135G carriers were also observed in H. pylori-positive patients [0·3 (0) vs. 0·1 (0), P = 0·002] and H. pylori-positive patients with gastritis [0·4 (0) vs. 0·1 (0), P = 0·002] but were not found in H. pylori-negative patients. Our findings revealed that a combination of H. pylori infection and RAD51 G135C genotype of the host showed an increasing score for intestinal metaplasia. Therefore, RAD51 G135C might be the important predictor for gastric cancer of H. pylori-infected patients.

The Prevalence of Helicobacter pylori Virulence Factors in Bhutan, Vietnam, and Myanmar Is Related to Gastric Cancer Incidence

Gastric cancer is a significant health problem in Asia. Although the prevalence of Helicobacter pylori infection is similar in Bhutan, Vietnam, and Myanmar, the incidence of gastric cancer is highest in Bhutan, followed by Vietnam and Myanmar. We hypothesized that H. pylori virulence factors contribute to the differences. The status of cagA, vacA, jhp0562, and β-(1,3)galT(jhp0563) was examined in 371 H. pylori-infected patients from Bhutan, Vietnam, and Myanmar. Each virulence factor could not explain the difference of the incidence of gastric cancer. However, the prevalence of quadruple-positive for cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative was significantly higher in Bhutan than in Vietnam and Myanmar and correlated with gastric cancer incidence. Moreover, gastritis-staging scores measured by histology of gastric mucosa were significantly higher in quadruple-positive strains. We suggest that the cagA, vacA s1, vacA m1, and jhp0562-positive/β-(1,3)galT-negative genotype may play a role in the development of gastric cancer.

Toll-like Receptor 10 in Helicobacter pylori Infection

Innate immunity plays important roles in the primary defense against pathogens, and epidemiological studies have suggested a role for Toll-like receptor 1 (TLR1) in Helicobacter pylori susceptibility. Microarray analysis of gastric biopsy specimens from H. pylori-positive and uninfected subjects showed that TLR10 messenger RNA (mRNA) levels were upregulated approximately 15-fold in infected subjects; these findings were confirmed by real-time quantitative polymerase chain reaction analysis. Immunohistochemical investigation showed increased TLR10 expression in the gastric epithelial cells of infected individuals. When H. pylori was cocultured with NCI-N87 gastric cells, both TLR10 and TLR2 mRNA levels were upregulated. We compared the ability of TLR combinations to mediate nuclear factor-κB (NF-κB) activation. Compared with other TLR2 subfamily heterodimers, the TLR2/TLR10 heterodimer mediated the greatest NF-κB activation following exposure to heat-killed H. pylori or H. pylori lipopolysaccharide. We conclude that TLR10 is a functional receptor involved in the innate immune response to H. pylori infection and that the TLR2/TLR10 heterodimer functions in H. pylori lipopolysaccharide recognition.

Appropriate first-line regimens to combat Helicobacter pylori antibiotic resistance: an Asian perspective

Asia has the largest population of any continent and the highest incidence of gastric cancer in the world, making it very important in the context of Helicobacter pylori infection. According to current guidelines, standard triple therapy containing a proton pump inhibitor (PPI) and two antibiotics; amoxicillin (AMX) and clarithromycin (CAM) or metronidazole (MNZ), is still the preferred first-line regimen for treatment of H. pylori infection. However, the efficacy of legacy triple regimens has been seriously challenged, and they are gradually becoming ineffective. Moreover, some regions in Asia show patterns of emerging antimicrobial resistance. More effective regimens including the bismuth and non-bismuth quadruple, sequential, and dual-concomitant (hybrid) regimens are now replacing standard triple therapies as empirical first-line treatments on the basis of the understanding of the local prevalence of H. pylori antimicrobial resistance. Selection of PPI metabolized by the non-enzymatic pathway or minimal first pass metabolism and/or increasing dose of PPI are important to increase H. pylori eradication rates. Therefore, local antibiotic resistance surveillance updates, selection of appropriate first-line regimens with non-enzymatic PPI and/or increased doses of PPI, and detailed evaluation of patients' prior antibiotic usage are all essential information to combat H. pylori antibiotic resistance in Asia.

Differences in interleukin 8 expression in Helicobacter pylori-infected gastric mucosa tissues from patients in Bhutan and the Dominican Republic

The outcomes of Helicobacter pylori infection vary geographically. H pylori strains, disease presentation, and environments differ markedly in Bhutan and Dominican Republic. The aims were to compare the strains, histology, and expression of interleukin (IL) 8 and IL-10 from gastric mucosa from the 2 countries. H pylori status was assessed by the combination of rapid urease test, culture, and histology. Histology was evaluated using the updated Sydney System, and cytokines in gastric biopsies were measured using real-time polymerase chain reaction (PCR). There were 138 subjects from Bhutan and 155 from Dominican Republic. The prevalence of H pylori infection was 65% and 59%, respectively. The genotype of cagA was predominantly East Asian type in Bhutan versus Western type in Dominican Republic. Gastritis severity was significantly higher in H pylori-infected subjects from Bhutan than those from Dominican Republic. IL-8 expression by H pylori infection was 5.5-fold increased in Bhutan versus 3-fold in Dominican Republic (P < .001); IL-10 expression was similar. IL-8 expression levels among H pylori-infected cases tended to be positively correlated with polymorphonuclear leucocyte and monocyte infiltration scores in both countries. IL-8 expression among those with grade 2 and 3 polymorphonuclear leucocyte and monocyte infiltration was significantly higher in Bhutan than in Dominican Republic. The difference in IL-8 expression in the 2 countries is reflected in the different disease pattern between them. Whether the dominant factor is differences in H pylori virulence, in host-H pylori-environmental interactions, genetic factors or all remains unclear. However, severity of inflammation appears to be a critical factor in disease pathogenesis. We compared IL-8 messenger RNA levels between the high gastric cancer risk country, Bhutan (mainly East Asian-type H pylori), and the lower gastric cancer risk country, Dominican Republic (mainly Western-type H pylori).

Helicobacter pylori infection introduces DNA double-strand breaks in host cells

Gastric cancer is an inflammation-related malignancy related to long-standing acute and chronic inflammation caused by infection with the human bacterial pathogen Helicobacter pylori. Inflammation can result in genomic instability. However, there are considerable data that H. pylori itself can also produce genomic instability both directly and through epigenetic pathways. Overall, the mechanisms of H. pylori-induced host genomic instabilities remain poorly understood. We used microarray screening of H. pylori-infected human gastric biopsy specimens to identify candidate genes involved in H. pylori-induced host genomic instabilities. We found upregulation of ATM expression in vivo in gastric mucosal cells infected with H. pylori. Using gastric cancer cell lines, we confirmed that the H. pylori-related activation of ATM was due to the accumulation of DNA double-strand breaks (DSBs). DSBs were observed following infection with both cag pathogenicity island (PAI)-positive and -negative strains, but the effect was more robust with cag PAI-positive strains. These results are consistent with the fact that infections with both cag PAI-positive and -negative strains are associated with gastric carcinogenesis, but the risk is higher in individuals infected with cag PAI-positive strains.

Epidemiology of Helicobacter pylori infection

Medline and PubMed databases were searched on epidemiology of Helicobacter pylori for the period of April 2013-March 2014. Several studies have shown that the prevalence of H. pylori is still high in most countries. In north European and North American populations, about one-third of adults are still infected, whereas in south and east Europe, South America, and Asia, the prevalence of H. pylori is often higher than 50%. H. pylori remains highly prevalent in immigrants coming from countries with high prevalence of H. pylori. However, the lower prevalence of infection in the younger generations suggests a further decline of H. pylori prevalence in the coming decades. Low socioeconomic conditions in childhood are confirmed to be the most important risk factors for H. pylori infection. Although the way the infection is transmitted is still unclear, interpersonal transmission appears to be the main route. Finally, H. pylori recurrence after successful eradication can still occur, but seems to be an infrequent event.

Virulence genes of Helicobacter pylori in the Dominican Republic

Although the incidence of gastric cancer in the Dominican Republic is not high, the disease remains a significant health problem. We first conducted a detailed analysis of Helicobacter pylori status in the Dominican Republic. In total, 158 patients (103 females and 55 males; mean age 47.1±16.2 years) were recruited. The status of H. pylori infection was determined based on four tests: rapid urease test, culture test, histological test and immunohistochemistry. The status of cagA and vacA genotypes in H. pylori was examined using PCR and gene sequencing. The overall prevalence of H. pylori infection was 58.9 %. No relationship was found between the H. pylori infection rate and the age range of 17-91 years. Even in the youngest group (patients aged <29 years), the H. pylori infection rate was 62.5 %. Peptic ulcer was found in 23 patients and gastric cancer was found in one patient. The H. pylori infection rate in patients with peptic ulcer was significantly higher than that in patients with gastritis (82.6 versus 54.5 %, P<0.01). The cagA-positive/vacA s1m1 genotype was the most prevalent (43/64, 67.2 %). Compared with H. pylori-negative patients, H. pylori-positive patients showed more severe gastritis. Furthermore, the presence of cagA was related to the presence of more severe gastritis. All CagA-positive strains had Western-type CagA. In conclusion, we found that H. pylori infection is a risk factor for peptic ulcer in the Dominican Republic. Patients with cagA-positive H. pylori could be at higher risk for severe inflammation and atrophy.

Identification of Helicobacter pylori infection in symptomatic patients in Surabaya, Indonesia, using five diagnostic tests

SUMMARY The prevalence of Helicobacter pylori infection in Indonesia is controversial. We examined the H. pylori infection rate in 78 patients in a hospital in Surabaya using five different tests, including culture, histology, immunohistochemistry, rapid urease test, and urine antibody test. Furthermore, we analysed virulence factors in H. pylori strains from Indonesia. The H. pylori infection rate was only 11.5% in all patients studied, and 2.3% of Javanese patients and 18.0% of Chinese patients were infected (P = 0.01). Although severe gastritis was not observed, activity and inflammation were significantly higher in patients positive for H. pylori than in patients negative for H. pylori. Among genotypes identified from five isolated strains, cagA was found in four; two were vacA s1m1. All cagA-positive strains were oipA 'on' and iceA1 positive. We confirmed both a low H. pylori infection rate and a low prevalence of precancerous lesions in dyspeptic patients in a Surabaya hospital, which may contribute to the low incidence of gastric cancer in Indonesia.

Prevalence of and risk factors for Helicobacter pylori infection in Chinese military personnel

AIM: To investigate the prevalence of and risk factors for Helicobacter pylori (H. pylori) infection in Chinese military personnel.

METHODS: Using cluster sampling method, a questionnaire survey was conducted in 510 soldiers in the southern China. The questionnaire consisted of 67 items related to H. pylori infection. H. pylori infection was detected by measurement of serum H. pylori IgG antibody and by the ¹⁴C breath test. The risk factors for H. pylori infection were analyzed.

RESULTS: A total of 510 subjects completed the questionnaire and received H. pylori detection. The prevalence of H. pylori infection was 59.2%. H. pylori infection was positively associated with age, service duration, collective accommodation time, number of family members before joining the army, eating ginger and potato and their products, and negatively related with the use of detergent when washing dishes. Married soldiers and those having a collective life history before joining the army soldiers had significantly higher H. pylori infection rates.

CONCLUSION: The prevalence of H. pylori infection in Chinese soldiers was 59.2%. H. pylori infection is associated with age, service duration, collective accommodation time, marriage, number of family members and collective life history before joining the army, and eating habits in Chinese soldiers.

Nationwide survey of Helicobacter pylori antibiotic resistance in Thailand

The objectives of this study are to survey the antibiotic-resistant pattern of Helicobacter pylori infection in different geographical locations in Thailand and to determine factors associated with antibiotic resistance. Dyspeptic patients undergoing upper gastrointestinal endoscopy from the Northern, Northeastern, Central, and Southern regions of Thailand between January 2004 and December 2012 were enrolled in this study. Two antral gastric biopsies were obtained for culture; susceptibility tests were performed using E-test. A total of 3964 were enrolled, and 1350 patients (34.1%) were infected with H. pylori as identified by rapid urease test. Cultures were positive in 619 isolates. E-test for amoxicillin, clarithromycin, metronidazole, and tetracycline were successful in 400 isolates and for levofloxacin and ciprofloxacin in 208 isolates. Antibiotic resistance was present in 50.3% including amoxicillin 5.2%, tetracycline 1.7%, clarithromycin 3.7%, metronidazole 36%, ciprofloxacin 7.7%, levofloxacin 7.2%, and multi-drugs in 4.2%. Clarithromycin resistance was significantly more common in those older than 40 years (i.e., 100% versus 0%; P = 0.04). The prevalence of metronidazole resistant in Southern Thailand was significantly higher than in the Northeastern region (66.7% versus 33.3% P = 0.04). Metronidazole resistance remains the most common antibiotic resistant type of H. pylori in Thailand. The pattern of H. pylori antibiotic resistance over 9 years demonstrated a fall in clarithromycin resistance such that currently age >40 years is a predictor for clarithromycin resistance in Thailand. Quinolone resistance is a growing problem.

Seroprevalence of Helicobacter pylori infection and gastric mucosal atrophy in Bhutan, a country with a high prevalence of gastric cancer

Gastric cancer is the second leading cause of cancer-related mortality in the world. Recently, serum Helicobacter pylori antibodies and pepsinogen (PG) have been used for gastric cancer screening. The incidence of gastric cancer in Bhutan is reported to be quite high compared with that in neighbouring countries. In this study, 381 subjects from three areas of Bhutan were assessed for gastric mucosal atrophy and serological parameters. Anti-H. pylori IgG, PG I, PG II and cytotoxin-associated gene A (CagA) antibodies were measured using ELISA. Subjects were classified into four groups according to H. pylori and PG seropositivity: Group A (H. pylori-negative/PG-negative), Group B (H. pylori-positive/PG-negative), Group C (H. pylori-positive/PG-positive) and Group D (H. pylori-negative/PG-positive). The prevalence of H. pylori in the 381 subjects was 71.1% (271/381), with high infection rates found in rural areas. The PG I/II ratio was significantly inversely correlated with the atrophy score in the antrum and the corpus (P<0.001). Multivariate analysis showed that the PG status was significantly associated with the presence of atrophy in the corpus. The prevalence of the PG-positive status was significantly higher among H. pylori-positive subjects than among H. pylori-negative subjects (P<0.001). Based on the ABC method, Group B was the most dominant, followed by Group A, Group C and Group D. The high incidence of gastric cancer in Bhutan can be attributed to the high prevalence of H. pylori infection and gastric mucosal atrophy.