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    Helicobacter Pylori Genotyping Among Mongolian Dyspeptic Patients
    (Mongolian National University of Medical Sciences, 2022-06-30)
    Tserentogtokh Tegshee
    ;
    ; ; ;
    Battulga Adiyasuren
    Objective: The prevalence of H. pylori infection varies significantly and developing countries are found to be the highest in Asia. In the present study, we have aimed to perform a combined analysis of histochemical stains and IHC to confirm the H.pylori infection of patients in 5 different provinces and Ulaanbaatar city, Mongolia. Method: Five hundred and thirty-eight patients were enrolled in this study (142 gastric mucosal atrophy, 333 gastritis and 62 gastroesophageal reflux). Results: 67.1 % of participants had CagA positive and 69.3 % were immunohistochemically positive. All histological results showed that the gastritis group was significantly higher in patients who were positive for H. pylori than in antral-predominant gastritis. By the hematoxylin and eosin staining with May– Giemsa confirmation by IHC, the prevalence of H. pylori infection in the gastric mucosal atrophy group was 62.1 %, while in the gastritis and gastroesophageal reflux group, the rate was 74.3 % and 59.1 %, respectively. Conclusion: CagA sequence profile in each group of patients revealed that 22.6 % of the gastric mucosal atrophy group was ABC type, 43.4 % was ABCC type and 33.9 % was ABTC type. On the other hand, in the gastritis group, the dominant type was ABTC (41.3 %). In the gastroesophageal reflux group, the ABCC type was dominant while 23.1% was the ABC type.
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    1257 ENTEROCCUS HIRAE ATTENUATES CHEMOKINE AND INDUCES DNA DAMAGE IN GASTRIC EPITHELIAL CELLS
    (Elsevier BV, 2023-05-01) ; ;
    Ricky Indra Alfaray
    ;
    Junko K. Akada
    ;
    Takashi Matsumoto
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    IDDF2023-ABS-0237 Characteristics of helicobacter pylori from mongolia where burdening high incidence of gastric cancer
    (2023-06-01) ; ; ;
    Yoshio Yamaoka
    ;
    Vo Phuoc Tuan
    Background Globally Mongolia is the top country in the incidence of gastric cancer followed by Japan and Korea which are East Asian countries. Helicobacter pylori (H. pylori) infection possessing East-Asian-type CagA is more associated with gastric carcinogenesis than Western-type CagA. The prevalence of H. pylori is around 70% in Mongolia; however, the previous study reported Mongolians infected with H. pylori possessing Western-type CagA. Therefore, we aimed to characterize Mongolian H. pylori infection based on a whole genome sequencing method. Methods Totally 130 strains are sequenced from Mongolian H. pylori isolates (20 gastric cancer and 110 non-cancer cases) and 401 data from 38 countries H. pylori whole genome data were extracted for the FineStructure analysis. The complete CagA gene and 7 housekeeping genes were extracted for constructing a phylogenetic tree. Results Based on whole genomic FineStructure analysis we found new H. pylori population named as HpMongolia among Mongolian gastric cancer and non-gastric cancer cases which are separately clustered among published global H. pylori populations (IDDF2023-ABS-0237-Figure 1. FineStructure analysis for H.pylori population). Complete CagA gene sequencing data showed that HpMongolia possessed with J-Western type cagA and it was the highest distribution of J-Western cagA positive H. pylori strains identified in Mongolia (67.7%) followed by Canada, North America (10%), and Okinawa, Japan (5.9%) among the published population (IDDF2023-ABS-0237-Figure 2. Global H.pylori phylogenetic tree based on 7-housekeeping genes). The phylogenetic tree constructed based on 7 housekeeping genes result showed the closest H. pylori population with HpMongolia is the HpAmerind which is isolated from native American people (IDDF2023-ABS-0237-Figure 3. H.pylori CagA genotyping map). Conclusions Mongolians provide new H. pylori population is named as HpMongolia which contains most of the cases Japanese-Western type cagA both for cancer and non-cancer cases. Therefore Japanese-Western type cagA might have advantageous for human migration study markers and further clinical implications.
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    IDDF2023-ABS-0226 Initial results of screening program in mongolia where burdening high gastric cancer
    Background Mongolia is the leading country in the incidence and mortality rate of gastric cancer. According to the national data, TNM stage at the time of cancer diagnosis, a gastric cancer diagnosis is 0.4% in the carcinoma-in-situ stage, 5.1% in stage I, 15.2% in stage II, 42.7% in stage III and 36.5% in stage IV 36.5% were diagnosed respectively. Whereas almost 80% of people are diagnosed with early-stage of gastric cancer in Japan and Korea, where national cancer screening programs have been initiated for several decades. In 2022 national cancer screening program for upper gastrointestinal neoplasia was initiated; therefore, we aimed to conduct a multi-center study to determine gastric cancer incidence among the Mongolian population. Methods The cross-sectional study was performed to examine the detection rate of gastric cancer cases based on a national screening program from May to December 2022. The primary outcomes of this study were to define the detection rate (proportion of positive cases among individuals who underwent endoscopic screening) and to determine the characteristics of the cancer type, including its precursor disease based on histological examination. Results During the screening program, a total of 34581 participants’ data were collected from 28 endoscopy centers from Ulaanbaatar city and the western eastern, southern, and northern parts of the Mongolian province’s hospitals. The age range of the study participants was 35 to 93 years old. In terms of gender, 56.8% are men and 43.13% are women. The mean with SD age of people diagnosed with gastric cancer was 61.56±1.11, while the mean with SD age of healthy people was 53.84 ± 0.29 (p-value 0.0001). Among them, 113 (0.1%) patients were diagnosed with gastric cancer. The proportion of early-stage gastric cancer cases was 34 (30%) based on endoscopic and histological evaluation. The overall cases included in the national screening program are summarized in Figure 1 (IDDF2023-ABS-0226 Figure 1. Initial result from the national screening program for gastric cancer). Conclusions The initiation of the Mongolian national gastric cancer screening program could increase to detect the proportion of gastric cancer in its early stage. Therefore, screening programs should be continuous further. However, the quality of endoscopic examination should be improved.
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    IDDF2022-ABS-0128 A novel pathogen enterococcus hirae induced dysbiosis in the stomach and the genomic instability to promote gastric cancer
    (2022-09-01) ; ;
    Junko K. Akada
    ;
    Takashi Matsumoto
    ;
    Ricky Indra Alfaray
    Background Previous our microbiome analysis indicates that Enterococcus sp. predominance of microbial composition has been determined in patients with gastric cancer (GC) by 16S rRNA metagenomic analysis. We aimed to determine whether this bacterium could promote the emergence and progression of GC. Methods The effects of E. hirae and Helicobacter pylori (clinical strain Mon-Ke2 as control) were assessed in a gastric epithelial cell line (AGS cells). The cell toxicity of AGS cells is identified by lactate dehydrogenase levels. The DNA double-strand breaks (DSBs) were assessed by gamma-H2AX expressions using immunoblotting; and single-cell gel electrophoresis (SCGE). AGS cells were analyzed for the rapid oxygen species (ROS) expressions response after E. hirae and H. pylori infections. Results E. hirae was successfully isolated from the gastric mucosal specimen of a GC patient for the first time. The whole-genome sequence of E. hirae was confirmed by next-generation sequencing. E. hirae-infected AGS cells showed abnormal morphological changes. Infections of E. hirae and H. pylori significantly induced cell death and expression of gH2AX in AGS cells. Besides, the expression of gH2AX and DSBs was confirmed by SCGE comet formation. Interestingly, co-infection of H. pylori and E. hirae had a synergistic effect on the severity of DSBs. E. hirae could induce intranucleus and mitochondrial ROS in AGS cells same as H. pylori. We investigated whether only live E. hirae, or its released factor(s) can cause DNA damage. Supernatant from AGS cells infected with E. hirae could induce the gH2AX, whereas H. pylori required cell adhesion to induce gH2AX. The complete genome of E. hirae totally contained 2570 genes and 10 known virulence factor genes (e.g., Enterococcus pore-forming toxin). Conclusions E. hirae-related dysbiosis in the stomach might increase the risk for GC, resulting in gained the genomic instability of gastric cells, as well as H. pylori infection. Further research investigating the impacts of this pathogen on the human host using the gastric organoid model is needed since several studies have shown that other species of Enterococcus induce cancer-promoting events resulting in DNA damage in gastric/colonic mucosa, and hepatic cells.
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    High Antibiotic Resistance of Helicobacter pylori and Its Associated Novel Gene Mutations among the Mongolian Population
    (MDPI AG, 2020-07)
    Azzaya, Dashdorj
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    ; ; ;
    Matsumoto, Takashi
    Mongolia has a high prevalence of Helicobacter pylori infection and the second highest incidence of gastric cancer worldwide. Thus, investigating the prevalence of antibiotic resistance and its underlying genetic mechanism is necessary. We isolated 361 H. pylori strains throughout Mongolia. Agar dilution assays were used to determine the minimum inhibitory concentrations of five antibiotics; amoxicillin, clarithromycin, metronidazole, levofloxacin, and minocycline. The genetic determinants of antibiotic resistance were identified with next-generation sequencing (NGS) and the CLC Genomics Workbench. The resistance to metronidazole, levofloxacin, clarithromycin, amoxicillin, and minocycline was 78.7%, 41.3%, 29.9%, 11.9% and 0.28%, respectively. Multidrug resistance was identified in 51.3% of the isolates investigated which were further delineated into 9 antimicrobial resistance profiles. A number of known antibiotic resistance mutations were identified including rdxA, frxA (missense, frameshift), gyrA (N87K, A88P, D91G/N/Y), 23S rRNA (A2143G), pbp1A (N562Y), and 16S rRNA (A928C). Furthermore, we detected previously unreported mutations in pbp1A (L610*) and the 23S rRNA gene (A1410G, C1707T, A2167G, C2248T, and C2922T). The degree of antibiotic resistance was high, indicating the insufficiency of standard triple therapy in Mongolia.
    Scopus© Citations 36
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    Gastric mucosal microbiota in a Mongolian population with gastric cancer and precursor conditions
    (Wiley, 2020-04) ;
    El Serag, Hashem B
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    Matsumoto, Takashi
    ;
    Ajami, Nadim J
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    Uchida, Tomohisa
    BACKGROUND: Incidence and mortality of gastric cancer (GC) are high in Mongolia despite Helicobacter pylori in the Mongolian population being less virulent. AIM: To evaluate gastric bacterial microbiota profiles in patients with GC and its precursor histological conditions. METHODS: We conducted a case-control study among 48 GC and 120 noncancer patients (20 normal gastric mucosa [control], 20 gastritis, 40 with atrophy and 40 intestinal metaplasia [IM]). We performed 16S rRNA gene amplicon sequencing and compared taxonomic and functional prediction profiles based on the diagnosis group and H pylori infection status. RESULTS: The highest overall bacterial alpha diversity metrics were observed in the control group, followed by the IM and cancer groups. The gastritis and atrophy groups had the least diversity. Lactobacilli and Enterococci were the dominant genus in several cancer patients especially in the absence of H pylori. In addition, Carnobacterium, Glutamicibacter, Paeniglutamicibacter, Fusobacterium and Parvimonas were associated with GC regardless of H pylori infection. Firmicutes were decreased in the gastritis and atrophy groups and increased in the IM and cancer groups. The functional metabolic activity of the Embden-Meyerhof-Parnas pathway and the utilization of sugar, were significantly increased in cancer group compared with the noncancer group. CONCLUSION: Microbial factors other than H pylori may play a role in Mongolian GC. We identified novel associations between GC and the genera Enterococcus, Lactobacillus, Carnobacterium, Glutamicibacter, Paeniglutamicibacter, Fusobacterium, and Parvimonas.
    Scopus© Citations 98
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    Species-level dynamics of gastric microbiome after Helicobacter pylori eradication in high-risk Mongolian population
    (2026-02) ; ;
    Khangai, Ayush
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    ;
    Luvsandagva, Bayasgalan
    BACKGROUND: Species-level resolution is essential to understand gastric microbiome recovery after Helicobacter pylori eradication, yet short-read 16 S rRNA approaches often obscure clinically relevant changes. METHODS: Gastric biopsies from 121 adults in Bayan-Ölgii, Mongolia (71 H. pylori-positive, 50 H. pylori-negative) were analyzed, including nine paired pre- and post-eradication gastric biopsy samples collected six months apart, enabling exploratory longitudinal analysis. Full-length 16 S rRNA (V1-V9) sequencing was performed using the Oxford Nanopore platform with EMU taxonomic assignment (SILVA v138.1/NCBI RefSeq). Ecological changes were evaluated using diversity indices, principal coordinates analysis (PCoA) with PERMANOVA, and differential abundance testing (DESeq2, FDR < 0.05). Eradication therapy (esomeprazole-bismuth-doxycycline-levofloxacin) achieved success in 54 of 57 H. pylori-positive patients (94.7%). RESULTS: H. pylori-positive microbiomes were dominated by H. pylori (91.8% ± 3.9%) and exhibited markedly reduced diversity (Shannon = 0.44 ± 0.11) compared with H. pylori-negative samples (2.08 ± 0.25; p < 0.001). Six months after eradication, diversity increased significantly (2.17 ± 0.20; p = 0.0001), with enrichment of oral commensals including Streptococcus mitis (↑ 11.9×), Neisseria elongata (↑ 13.7×), and Prevotella melaninogenica (↑ 13.0×). However, post-eradication profiles at six months remained distinct from H. pylori-negative communities (PERMANOVA R² = 0.12; p = 0.02). In total, 174 amplicon sequence variants changed significantly, including persistence of Fusobacterium nucleatum. CONCLUSIONS: Nanopore full-length 16 S sequencing reveals fine-scale, clinically relevant shifts that are masked by partial-gene assays. Eradication rapidly restores microbial diversity, but at six months, is associated with a novel ecological equilibrium rather than complete normalization. This species-resolved approach offers a practical framework for post-eradication microbiome monitoring and may inform strategies to reduce residual gastric cancer risk in high-burden populations.
    Scopus© Citations 1
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    Study of Helicobacter pylori Isolated from a High-Gastric-Cancer-Risk Population: Unveiling the Comprehensive Analysis of Virulence-Associated Genes including Secretion Systems, and Genome-Wide Association Study
    (MDPI AG, 2023-09) ;
    Alfaray, Ricky Indra
    ;
    ; ;
    Khangai, Ayush
    BACKGROUND: The prevalence of gastric cancer in Mongolia, in East Asia, remains the highest in the world. However, most Helicobacter pylori strains in Mongolia have a less virulent Western-type CagA. We aimed to determine how H. pylori genomic variation affected gastric diseases, especially gastric cancer, based on comprehensive genome analysis. METHODS: We identified a set of 274 virulence-associated genes in H. pylori, including virulence factor and outer membrane protein (OMP) genes, the type four secretion system gene cluster, and 13 well-known virulence gene genotypes in 223 H. pylori strains and their associations with gastric cancer and other gastric diseases. We conducted a genome-wide association study on 158 H. pylori strains (15 gastric cancer and 143 non-gastric cancer strains). RESULTS: Out of 274 genes, we found 13 genes were variable depending on disease outcome, especially iron regulating OMP genes. H. pylori strains from Mongolia were divided into two main subgroups: subgroup (Sg1) with high risk and Sg2 with low risk for gastric cancer. The general characteristics of Sg1 strains are that they possess more virulence genotype genes. We found nine non-synonymous single nucleotide polymorphisms in seven genes that are linked with gastric cancer strains. CONCLUSIONS: Highly virulent H. pylori strains may adapt through host-influenced genomic variations, potentially impacting gastric carcinogenesis.
    Scopus© Citations 10