Diagnostic strategy of irritable bowel syndrome: a low- and middle-income country perspective.

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder associated with substantial impairment which considerably burdens healthcare systems worldwide. Research on IBS has largely been conducted in high-income countries posing barriers to the application of diagnostic strategies in low- and middle-income countries (LMICs) due to differences in disease characteristics, healthcare resources, and socioeconomic factors. This review discusses the diagnostic issues associated with LMICs. We present a concise overview of the relevant approaches and propose a diagnostic strategy based on the latest evidence. A positive diagnostic strategy that relies on appropriate symptom-based criteria is crucial within the diagnostic framework. A combination of complete blood count, fecal occult blood test, and complete stool test may reliably identify individuals with suspected IBS who are more likely to have organic diseases, thus justifying the necessity for a colonoscopy. Eventually, we developed a diagnostic algorithm based on a limited setting perspective that summarizes the available evidence and may be applied in LMICs.

Genetic determinants of Biofilm formation of Helicobacter pylori using whole-genome sequencing.

BACKGROUND: Infection with Helicobacter pylori as the cause of gastric cancer is a global public health concern. In addition to protecting germs from antibiotics, biofilms reduce the efficacy of H. pylori eradication therapy. The nucleotide polymorphisms (SNPs) related with the biofilm forming phenotype of Helicobacter pylori were studied. RESULTS: Fifty-six H. pylori isolate from Bangladeshi patients were included in this cross-sectional study. Crystal violet assay was used to quantify biofilm amount, and the strains were classified into high- and low-biofilm formers As a result, strains were classified as 19.6% high- and 81.4% low-biofilm formers. These phenotypes were not related to specific clades in the phylogenetic analysis. The accessories genes associated with biofilm from whole-genome sequences were extracted and analysed, and SNPs among the previously reported biofilm-related genes were analysed. Biofilm formation was significantly associated with SNPs of alpA, alpB, cagE, cgt, csd4, csd5, futB, gluP, homD, and murF (P < 0.05). Among the SNPs reported in alpB, strains encoding the N156K, G160S, and A223V mutations were high-biofilm formers. CONCLUSIONS: This study revealed the potential role of SNPs in biofilm formation and proposed a method to detect mutation in biofilm from whole-genome sequences.

Gastric microbiome changes in relation with Helicobacter pylori resistance.

INTRODUCTION: Inadequate antimicrobial treatment has led to multidrug-resistant (MDR) bacteria, including Helicobacter pylori (H. pylori), which one of the notable pathogens in the stomach. Antibiotic-induced changes in the microbiota can negatively affect the host. This study aimed to determine the influence of H. pylori resistance on the diversity and abundance of the stomach microbiome. METHODS: Bacterial DNA was extracted from biopsy samples of patients presenting dyspepsia symptoms with H. pylori positive from cultures and histology. DNA was amplified from the V3-V4 regions of the 16S rRNA gene. In-vitro E-test was used to detect antibiotic resistance. Microbiome community analysis was conducted through α-diversity, ß-diversity, and relative abundance. RESULTS: Sixty-nine H. pylori positive samples were eligible after quality filtering. Following resistance status to five antibiotics, samples were classified into 24 sensitive, 24 single resistance, 16 double resistance, 5 triple resistance. Samples were mostly resistant to metronidazole (73.33%; 33/45). Comparation of four groups displayed significantly elevated α-diversity parameters under the multidrug resistance condition (all P <0.05). A notable change was observed in triple-resistant compared to sensitive (P <0.05) and double-resistant (P <0.05) groups. Differences in ß-diversity by UniFrac and Jaccard were not significant in terms of the resistance (P = 0.113 and P = 0.275, respectively). In the triple-resistant group, the relative abundance of Helicobacter genera was lower, whereas that of Streptococcus increased. Moreover, the linear discriminant analysis effect size (LEfSe) was associated with the presence of Corynebacterium and Saccharimonadales in the single-resistant group and Pseudomonas and Cloacibacterium in the triple-resistant group. CONCLUSION: Our results suggest that the resistant samples showed a higher trend of diversity and evenness than the sensitive samples. The abundance of H. pylori in the triple-resistant samples decreased with increasing cohabitation of pathogenic bacteria, which may support antimicrobial resistance. However, antibiotic susceptibility determined by the E-test may not completely represent the resistance status.

Low-grade intestinal metaplasia in Indonesia: Insights into the expression of proinflammatory cytokines during Helicobacter pylori infection and unique East-Asian CagA characteristics.

Helicobacter pylori infection is a major cause of intestinal metaplasia. In this study, we aimed to understand the reason underlying the low grade and incidence of intestinal metaplasia in Indonesia, based on the expression of genes encoding proinflammatory cytokines in gastric biopsy specimens. The possible reasons for the lesser virulence of the East-Asian-type CagA in Indonesia than that of the Western-type CagA, which is not common in other countries, were also investigated. The mRNA expression of cytokines was evaluated using real-time PCR. CagA characteristics were analyzed using in silico analysis. The expression of cytokines was typically not robust, among H. pylori-infected subjects in Indonesia, despite them predominantly demonstrating the East-Asian-type CagA. This might partially be explained by the characteristics of the East-Asian-type CagA in Indonesia, which showed a higher instability index and required higher energy to interact with proteins related to the cytokine induction pathway compared with the other types (p < 0.001 and p < 0.05, respectively). Taken together, besides the low prevalence of H. pylori, the low inflammatory response of the host and low CagA virulence, even among populations with high infection rates, may play an essential role in the low grade and low incidence of intestinal metaplasia in Indonesia. We believe that these findings would be relevant for better understanding of intestinal metaplasia, which is closely associated with the development of gastric cancer.

A comprehensive evaluation of an animal model for Helicobacter pylori-associated stomach cancer: Fact and controversy.

Even though Helicobacter pylori infection was the most causative factor of gastric cancer, numerous in vivo studies failed to induce gastric cancer using H. pylori infection only. The utilization of established animal studies in cancer research is crucial as they aim to investigate the coincidental association between suspected oncogenes and pathogenesis as well as generate models for the development and testing of potential treatments. The methods to establish gastric cancer using infected animal models remain limited, diverse in methods, and showed different results. This study investigates the differences in animal models, which highlight different pathological results in gaster by literature research. Electronic databases searched were performed in PubMed, Science Direct, and Cochrane, without a period filter. A total of 135 articles were used in this study after a full-text assessment was conducted. The most frequent animal models used for gastric cancer were Mice, while Mongolian gerbils and Transgenic mice were the most susceptible model for gastric cancer associated with H. pylori infection. Additionally, transgenic mice showed that the susceptibility to gastric cancer progression was due to genetic and epigenetic factors. These studies showed that in Mongolian gerbil models, H. pylori could function as a single agent to trigger stomach cancer. However, most gastric cancer susceptibilities were not solely relying on H. pylori infection, and numerous factors are involved in cancer progression. Further study using Mongolian gerbils and Transgenic mice is crucial to conduct and establish the best models for gastric cancer associated H. pylori.

Analysis of gastric microbiota and Helicobacter pylori infection in gastroesophageal reflux disease.

BACKGROUND: We evaluated the microbiota in the stomach of Gastroesophageal Reflux Disease (GERD) patients. We compared Erosive Reflux Disease (ERD) to gastritis and Non-erosive Reflux Disease (NERD) subjects by 16S rRNA approach on gastric biopsy specimens. A total of 197 subjects were included consisting of gastritis (68; 34.52%), ERD (55; 27.92%), and NERD (74; 37.56%). After quality filtering, 187 samples were included for OTU analysis using Qiime2. RESULTS: We observed a significant difference in alpha diversity (Shannon and Simpson indexes were P = 0.0016 and P = 0.017, respectively). A significant decrease in alpha diversity index was observed in NERD with Helicobacter pylori (H. pylori)-positive subjects than in gastritis (Simpson index P = 0.022; Shannon index P = 0.029), indicating a significant influence of H. pylori on the diversity in the stomach despite the diseases. In H. pylori-negative samples, alpha diversity measurement by the abundance coverage estimates (ACE) and Fisher Test revealed that ERD had significantly lower richness than gastritis and NERD groups (P = 0.00012 and P = 0.00043, respectively). Anaerobacillus sp. could only be found in ERD patients by LEFse analysis. CONCLUSIONS: The presence of ERD could alter microbiome diversity. A negative correlation between H. pylori and ERD is shown in this microbiome study but not in NERD.

Antimicrobial Resistance Profile by Metagenomic and Metatranscriptomic Approach in Clinical Practice: Opportunity and Challenge.

The burden of bacterial resistance to antibiotics affects several key sectors in the world, including healthcare, the government, and the economic sector. Resistant bacterial infection is associated with prolonged hospital stays, direct costs, and costs due to loss of productivity, which will cause policy makers to adjust their policies. Current widely performed procedures for the identification of antibiotic-resistant bacteria rely on culture-based methodology. However, some resistance determinants, such as free-floating DNA of resistance genes, are outside the bacterial genome, which could be potentially transferred under antibiotic exposure. Metagenomic and metatranscriptomic approaches to profiling antibiotic resistance offer several advantages to overcome the limitations of the culture-based approach. These methodologies enhance the probability of detecting resistance determinant genes inside and outside the bacterial genome and novel resistance genes yet pose inherent challenges in availability, validity, expert usability, and cost. Despite these challenges, such molecular-based and bioinformatics technologies offer an exquisite advantage in improving clinicians' diagnoses and the management of resistant infectious diseases in humans. This review provides a comprehensive overview of next-generation sequencing technologies, metagenomics, and metatranscriptomics in assessing antimicrobial resistance profiles.

The role of non-Helicobacter pylori bacteria in the pathogenesis of gastroduodenal diseases.

Over the past decade, the development of next-generation sequencing for human microbiota has led to remarkable discoveries. The characterization of gastric microbiota has enabled the examination of genera associated with several diseases, including gastritis, precancerous lesions, and gastric cancer. Helicobacter pylori (H. pylori) is well known to cause gastric dysbiosis by reducing diversity, because this bacterium is the predominant bacterium. However, as the diseases developed into more severe stages, such as atrophic gastritis, premalignant lesion, and gastric adenocarcinoma, the dominance of H. pylori began to be displaced by other bacteria, including Streptococcus, Prevotella, Achromobacter, Citrobacter, Clostridium, Rhodococcus, Lactobacillus, and Phyllobacterium. Moreover, a massive reduction in H. pylori in cancer sites was observed as compared with noncancer tissue in the same individual. In addition, several cases of H. pylori-negative gastritis were found. Among these individuals, there was an enrichment of Paludibacter, Dialister, Streptococcus, Haemophilus parainfluenzae, and Treponema. These remarkable findings suggest the major role of gastric microbiota in the development of gastroduodenal diseases and led us to the hypothesis that H. pylori might not be the only gastric pathogen. The gastric microbiota point of view of disease development should lead to a more comprehensive consideration of this relationship.

Urease Levels and Gastritis Stage in Dyspeptic Patients.

BACKGROUND: Dyspepsia is a frequent main symptom of inpatients and outpatients scenario in Indonesia. However, the number of endoscopy facilities are still low, thus the use of non-invasive method to detect gastritis is necessary. We measured the relationship between urease levels and the stage of gastritis in dyspeptic adult patients. METHODS: A cross-sectional study included outpatient dyspepsia patient from November 2018 to February 2019. We examined 14C-Urea Breath Test (UBT) and determined the stage of gastritis based on the Updated Sydney System classification. RESULTS: The urease level of acute and chronic gastritis positive patients were higher than negative patients (p = 0.001, r = 0.353; p <0.0001, r = 0.433, respectively). The AUC value of 14C-UBT to detect acute, chronic, and atrophic gastritis are 0.889, 0.632 and 0.544, respectively. The best cut-off points of 14C-UBT to predict acute gastritis was ≥26.50δ‰ with sensitivity and specificity being 88.89% and 63.95%, respectively. Whereas the best cut-off points for chronic gastritis was ≥34.50δ‰ with 82.89% sensitivity, 63.16% specificity. As for atrophic gastritis, it showed very low AUC value, hence it is not a sufficient test modality to predict atrophic gastritis cases. CONCLUSION: 14C-UBT is sufficient for predicting acute or chronic gastritis but not for atrophic gastritis.

Next-Generation Sequencing-Based Study of Helicobacter pylori Isolates from Myanmar and Their Susceptibility to Antibiotics.

Evaluation of Helicobacter pylori resistance to antibiotics is crucial for treatment strategy in Myanmar. Moreover, the genetic mechanisms involved remain unknown. We aimed to investigate the prevalence of H. pylori infection, antibiotic resistance, and genetic mechanisms in Myanmar. One hundred fifty patients from two cities, Mawlamyine (n = 99) and Yangon (n = 51), were recruited. The prevalence of H. pylori infection was 43.3% (65/150). The successfully cultured H. pylori isolates (n = 65) were tested for antibiotic susceptibility to metronidazole, levofloxacin, clarithromycin, amoxicillin, and tetracycline by Etest, and the resistance rates were 80%, 33.8%, 7.7%, 4.6%, and 0%, respectively. In the multidrug resistance pattern, the metronidazole-levofloxacin resistance was highest for double-drug resistance (16/19; 84.2%), and all triple-drug resistance (3/3) was clarithromycin-metronidazole-levofloxacin resistance. Twenty-three strains were subjected to next-generation sequencing to study their genetic mechanisms. Interestingly, none of the strains resistant to clarithromycin had well-known mutations in 23S rRNA (e.g., A2142G, A2142C, and A2143G). New type mutation genotypes such as pbp1-A (e.g., V45I, S/R414R), 23S rRNA (e.g., T248C), gyrA (e.g., D210N, K230Q), gyrB (e.g., A584V, N679H), rdxA (e.g., V175I, S91P), and frxA (e.g., L33M) were also detected. In conclusion, the prevalence of H. pylori infection and its antibiotic resistance to metronidazole was high in Myanmar. The H. pylori eradication regimen with classical triple therapy, including amoxicillin and clarithromycin, can be used as the first-line therapy in Myanmar. In addition, next-generation sequencing is a powerful high-throughput method for identifying mutations within antibiotic resistance genes and monitoring the spread of H. pylori antibiotic-resistant strains.

Characterization of Helicobacter pylori tlyA and Its Association with Bacterial Density.

BACKGROUND: In the recent studies, a less virulent Helicobacter pylori variant could still colonize the human stomach and induce gastric inflammation, suggesting the involvement of other virulence factors, such as TlyA hemolysin. Nevertheless, the association of TlyA in the pathogenesis of H. pylori infection remains unclear. We investigated the tlyA profile and determined its relationship with gastritis severity. METHODS: An observational study was conducted using DNA stocks and secondary data from previous studies. The tlyA variant was examined by NGS and confirmed with polymerase chain reaction. Gastritis severity was categorized by the Updated Sydney System. The relationship between a variant of tlyA and gastritis severity was determined, in which discrete variables were tested using the χ2 test or Fisher exact test. RESULTS: Two H. pylori tlyA variants were observed and characterized as tlyA1 and tlyA2. We noted a unique variant in the amino acid sequence 32-35 that is exclusively detected among H. pylori isolated from the Papua island. In addition, we observed that the tlyA variant had a significant association with the H. pylori density in the antral (p = 0.002). Histological analyses revealed that TlyA1 was associated with higher H. pylori density than TlyA2. However, we did not observe any significant association of tlyA with the infiltration of inflammation cells. CONCLUSIONS: We observed 2 tlyA variants (tlyA1 and tlyA2). A significant association of tlyA with bacterial density suggested that tlyA plays a more significant role in the colonization process than its influence on the severity of inflammation in gastric mucosa.

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.

Helicobacter pylori BabA-SabA Key Roles in the Adherence Phase: The Synergic Mechanism for Successful Colonization and Disease Development.

Helicobacter pylori is a pathogenic microorganism that successfully inhabits the human stomach, colonizing it by producing several virulence factors responsible for preventing host self-defense mechanisms. The adherence mechanism to gastric mucosal tissue is one of the most important processes for effective colonization in the stomach. The blood group antigen-binding adhesion (BabA) and sialic acid-binding adherence (SabA) are two H. pylori outer membrane proteins able to interact with antigens in the gastroduodenal tract. H. pylori possesses several mechanisms to control the regulation of both BabA and SabA in either the transcriptional or translational level. BabA is believed to be the most important protein in the early infection phase due to its ability to interact with various Lewis antigens, whereas SabA interaction with sialylated Lewis antigens may prove important for the adherence process in the inflamed gastric mucosal tissue in the ongoing-infection phase. The adherence mechanisms of BabA and SabA allow H. pylori to anchor in the gastric mucosa and begin the colonization process.

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.

Diagnostic Value of 14C Urea Breath Test for Helicobacter pylori Detection Compared by Histopathology in Indonesian Dyspeptic Patients.

PURPOSE: Histopathology method is often used as a gold standard diagnostic for Helicobacter pylori infection in Indonesia. However, it requires an endoscopic procedure which is limited in Indonesia. A non-invasive method, such as 14C Urea Breath Test (UBT), is more favorable; however, this particular method has not been validated yet. PATIENTS AND METHODS: A total of 55 dyspeptic patients underwent gastroscopy and 14C-UBT test. We used Heliprobe® UBT for UBT test. As for the histology, May-Giemsa staining of two gastric biopsies (from the antrum and corpus) were evaluated following the Updated Sydney System. RESULTS: The Receiver Operating Characteristics analysis showed that the optimum cut-off value was 57 with excellence Area under Curve = 0.955 (95% CI = 0.861-1.000). By applying the optimum cut-off value, Heliprobe® UBT showed 92.31% for sensitivity, 97.62% for specificity, 92.31% for positive predictive value, 97.62% for negative predictive value, 38.77 for positive likelihood ratio, 0.0788 for negative likelihood ratio, and 96.36% for the accuracy. CONCLUSION: The 14C-UBT is an accurate test for H. pylori diagnosis with excellent sensitivity, specificity, and accuracy. The different optimum cut-off points suggested that a validation is absolutely necessary for new test prior application to the new population.

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.

CYP2C19 Polymorphisms in Indonesia: Comparison among Ethnicities and the Association with Clinical Outcomes.

CYP2C19 polymorphisms are important factors for proton pump inhibitor-based therapy. We examined the CYP2C19 genotypes and analyzed the distribution among ethnicities and clinical outcomes in Indonesia. We employed the polymerase chain reaction-restriction fragment length polymorphism method to determine the CYP2C19 genotypes and evaluated inflammation severity with the updated Sydney system. For CYP2C19*2, 46.4% were the homozygous wild-type allele, 14.5% were the homozygous mutated allele, and 39.2% were the heterozygous allele. For CYP2C19*3, 88.6% were the homozygous wild-type allele, 2.4% were the homozygous mutated allele, and 9.0% were the heterozygous allele. Overall, the prevalence of rapid, intermediate, and poor metabolizers in Indonesia was 38.5, 41.6, and 19.9%, respectively. In the poor metabolizer group, the frequency of allele *2 (78.8%) was higher than the frequency of allele *3 (21.2%). The Papuan had a significantly higher likelihood of possessing poor metabolizers than the Balinese (OR 11.0; P = 0.002). The prevalence of poor metabolizers was lower compared with the rapid and intermediate metabolizers among patients with gastritis and gastroesophageal reflux disease. Intermediate metabolizers had the highest prevalence, followed by rapid metabolizers and poor metabolizers. Dosage adjustment should therefore be considered when administering proton pump inhibitor-based therapy in Indonesia.

The Roles of IL-17, IL-21, and IL-23 in the Helicobacter pylori Infection and Gastrointestinal Inflammation: A Review.

Although millions of people have been infected by Helicobacter pylori (H. pylori), only a small proportion of infected individuals will develop adverse outcomes, ranging from chronic gastritis to gastric cancer. Advanced development of the disease has been well-linked with chronic inflammation, which is significantly impacted by the adaptive and humoral immunity response. From the perspective of cellular immunity, this review aims to clarify the intricate axis between IL-17, IL-21, and IL-23 in H. pylori-related diseases and the pathogenesis of inflammatory gastrointestinal diseases. CD4+ helper T (Th)-17 cells, with the hallmark pleiotropic cytokine IL-17, can affect antimicrobial activity and the pathogenic immune response in the gut environment. These circumstances cannot be separated, as the existence of affiliated cytokines, including IL-21 and IL-23, help maintain Th17 and accommodate humoral immune cells. Comprehensive understanding of the dynamic interaction between molecular host responses in H. pylori-related diseases and the inflammation process may facilitate further development of immune-based therapy.

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.

Overview of Helicobacter pylori Infection in Indonesia: What Distinguishes It from Countries with High Gastric Cancer Incidence?

Helicobacter pylori infects more than half the human population. However, the prevalence in Indonesia is low, as is the prevalence of gastric cancer. Hence, it could be instructive to compare these prevalence rates and their determining factors with those of countries that have high gastric cancer incidence. Ethnicity and genetic characteristics of H. pylori are important determinants of the H. pylori infection rate in Indonesia. The infection rate is higher in Bataknese, Papuans and Buginese than in Javanese, the predominant ethnic group. Ethnicity is also an important determinant of the genetic characteristics of H. pylori. Analysis of CagA in the EPIYA segment showed that the predominant genotypes in Papuans, Bataknese and Buginese are ABB-, ABDand ABC-type CagA, respectively. Meanwhile, in the countries with high gastric cancer incidence, almost all strains had East Asian type CagA. An antibiotic susceptibility evaluation showed that the standard triple therapy can still be used with caution in several cities. There is a very high rate of resistance to second-line regimens such as levofloxacin and metronidazole. Recent studies have shown that furazolidone, rifabutin and sitafloxacin are potential alternative treatments for antibiotic-resistant H. pylori infection in Indonesia. Rather than focusing on early detection and eradication as in countries with high gastric cancer prevalence, countries with low gastric cancer prevalence should focus on screening the several groups that have a high risk of gastric cancer.