The Helicobacter Pylori Genotyping Among Mongolian Dyspeptic Patients

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

Randomized Controlled Trial Comparing Standard Triple and Sequential Regimens for Helicobacter pylori Eradication

Objectives: The aim of this study was to compare effectiveness of sequential therapy to the standard triple therapy to eradicate Helicobacter pylori (H. pylori) in Mongolia. Methods: From September 2014 to February 2016, 140 patients with confirmed H. pylori infection (upper gastrointestinal tract (GI) endoscopy, rapid urease test, histology, H. pylori stool antigen test (HpStAg)) randomly received 10 days standard triple therapy (20 mg pantoprazole, 1 g amoxicillin, 500 mg clarithromycin, all twice daily for 10 days; STT group, n = 70), and sequential therapy (20 mg pantoprazole, 1 g amoxicillin twice daily for 5 days followed by 20 mg pantoprazole, 500 mg clarithromycin, 500 mg metronidazole twice daily for 5 days; SQT group, n = 70). Successful eradication therapy for H. pylori infection was defined as a negative HpStAg test 4 weeks after the end of eradication treatment. Results: The eradication rates by intention to treat (ITT) analysis were 71.4% (50/70) and 50% (35/70) in the STT and SQT groups, respectively (p = 0.033). The eradication rates by per-protocol (PP) analysis were 72.5% (50/69) and 51.5% (35/68) in the STT and SQT groups, respectively (p = 0.018). The adverse event rates were 7.6% (5/70) and 18.6% (13/70) in the STT and SQT groups, respectively (p = 0.043). Conclusion: The eradication rate was significantly higher in the STT group compared with the SQT group. But the eradication efficacies of both STT and SQT for H. pylori infection in Mongolia are unacceptable

Initial Trials With Susceptibility-Based and Empiric Anti-H. pylori Therapies in Mongolia

Background: Mongolia has a high prevalence of Helicobacter pylori infection and gastric cancer. We conducted a prospective, randomized, single-blind study to evaluate the efficacy of common regimens in Mongolia and to obtain specimens for susceptibility testing.Methods: Empiric treatments: 270 patients with confirmed H. pylori infection were randomized to receive 10 days clarithromycin-triple therapy (Clari-TT) (n = 90), modified bismuth quadruple therapy (M-BQT) (n = 90), or sequential therapy (ST) (n = 90). A second group of 46 patients received susceptibility-based Clari-TT. H. pylori was cultured from 131 patients and susceptibility testing was performed. H. pylori eradication was confirmed by stool antigen 4 weeks after the therapy.Results: Intention-to-treat (ITT) analysis cure rates were 71.1% (95% CI = 61.7–80.5%) for Clari-TT, 87.8% (95% CI = 81–94.6%) for M-BQT, 67.8% (95% CI = 58.1–77.5%) for ST vs. 89.1% (95% CI = 86–98.2%) for susceptibility-based Clari-TT. Per-protocol (PP) analysis results for these therapies were 72.7% (63.4–82%), 89.8% (83.5–96.1%), 68.5% (58.8–78.2%), and 97.6% (89.5–99.8%), respectively. Among 131 cultured H. pylori, resistance rates to amoxicillin, clarithromycin, and metronidazole were 8.4, 37.4, and 74%, respectively.Conclusion: In Mongolia, the prevalence of H. pylori resistance is high requiring bismuth quadruple therapy or susceptibility-based therapy to obtain acceptable cure rates

Gastric Microbiota in <i>Helicobacter pylori</i>-Negative and -Positive Gastritis Among High Incidence of Gastric Cancer Area

Helicobacter pylori (H. pylori) related chronic gastritis is a well-known major etiological factor for gastric cancer development. However, H. pylori-negative gastritis (HpN) is not well described. We aimed to examine gastric mucosal microbiota in HpN compared to H. pylori-positive gastritis (HpP) and H. pylori-negative non-gastritis group (control). Here, we studied 11 subjects with HpN, 40 with HpP and 24 controls. We performed endoscopy with six gastric biopsies. Comparison groups were defined based on strict histological criteria for the disease and H. pylori diagnosis. We used 16S rRNA gene amplicon sequencing to profile the gastric microbiota according to comparison groups. These results demonstrate that the HpP group had significantly lower bacterial richness by the operational taxonomic unit (OTU) counts, and Shannon and Simpson indices as compared to HpN or controls. The linear discriminant analysis effect size analysis showed the enrichment of Firmicutes, Fusobacteria, Bacteroidetes and Actinobacteria at phylum level in the HpN group. In the age-adjusted multivariate analysis, Streptococcus sp. and Haemophilus parainfluenzae were at a significantly increased risk for HpN (odds ratio 18.9 and 12.3, respectively) based on abundance. Treponema sp. was uniquely found in HpN based on occurrence. In this paper, we conclude that Streptococcus sp., Haemophilus parainfluenzae and Treponema sp. are candidate pathogenic bacterial species for HpN. These results if confirmed may have important clinical implications

Western-Type <i>Helicobacter pylori</i> CagA are the Most Frequent Type in Mongolian Patients

Helicobacter pylori infection possessing East-Asian-type CagA is associated with carcinogenesis. Mongolia has the highest mortality rate from gastric cancer. Therefore, we evaluated the CagA status in the Mongolian population. High risk and gastric cancer patients were determined using endoscopy and histological examination. H. pylori strains were isolated from different locations in Mongolia. The CagA subtypes (East-Asian-type or Western-type, based on sequencing of Glu-Pro-Ile-Tyr-Ala (EPIYA) segments) and vacA genotypes (s and m regions) were determined using PCR-based sequencing and PCR, respectively. In total, 368 patients were examined (341 gastritis, 10 peptic ulcer, and 17 gastric cancer). Sixty-two (16.8%) strains were cagA-negative and 306 (83.1%) were cagA-positive (293 Western-type, 12 East-Asian-type, and one hybrid type). All cagA-negative strains were isolated from gastritis patients. In the gastritis group, 78.6% (268/341) had Western-type CagA, 2.9% (10/341) had East-Asian-type, and 18.2% (61/341) were cagA-negative. However, all H. pylori from gastric cancer patients possessed Western-type CagA. Histological analyses showed that East-Asian-type CagA was the most virulent strains, followed by Western-type and cagA-negative strains. This finding agreed with the current consensus. CagA-positive strains were the most virulent type. However, the fact that different CagA types can explain the high incidence of gastric cancer might be inapplicable in Mongolia