BACKGROUND Helicobacter pylori (H.pylori), the main cause of gastric and duodenal ulcer, is considered as a type 1 carcinogen. The primary prevention of gastric cancer is eradicating chronic H.pylori infection. However, the antimicrobial eradication rates are decreasing as low as 80% in some countries, less than 70% in Europe and are inversely correlated with antibiotic resistance rates reported worldwide. The current international guidelines recommended several regimens with higher success rate including sequential, combined, bismuth-containing and resistance-guided treatment and states that the local susceptibility testing in H.pylori should be studied. The research data that is covering correlation between H.pylori associated gastric changes and precancerous diseases, evaluation of H.pylori eradication rate are sparse in Mongolia. METHODS Totally, 495 eligible candidates were enrolled into this study. 225 patients who visited to endoscopy unit, received gastroscopy with multiple biopsies for rapid urease test, histology and H.pylori culturing. Out of these, 131 (52.2%) patients were positive for H.pylori infection. These were further tested for antibiotic resistance. 76 patients were treated with targeted therapy based on antibiotic resistance testing. Another 270 eligible patients with confirmed H.pylori associated gastritis were randomized into the following 1st line therapy regimen groups clarithromycin-based triple therapy (CBTT, n=90); bismuth-based quadruple therapy (BBQT, n=90) and sequential therapy (ST, n=90). In 43 patients that were not responded to 1st line therapy, levofloxacin-based triple therapy (LBTT) was prescribed as a second line treatment. Eradication rates were assessed using H.pylori stool antigen test 28 days of therapy just subsequent to termination of treatment. RESULTS During the gastroscopy, presence of active gastritis, nodular change and atrophy were 32.9%, 12% and 52.9% respectively. Epigastric pain was reported in 73.3%, 62.2%, 60-80% and 41.3% of patients with normal mucosa, nodular change, stomach and duodenal ulcer and antral atrophy (p<0.05). Abdominal fullness was more common among patients with extensive gastric atrophy (69.2%, p<0.05). In <40 age group gastritis was predominantly in the prepylori, while in the >50 age group it was predominantly the corpus region. H.pylori resistance rates to amoxicillin, clarithromycin, metronidazole and more than 2 antibiotics were 8.4%, 37.4%, 74% and 30.5%. On ITT analysis, eradication rates of 1st line H.pylori targeted treatment, CBTT, BBQT and ST were 92.1%, 71.1%, 87.8% and 67.8% (p<0.0001); on PP analysis, that were 94.6%, 72.7%, 89.8% and 68.5% (p<0.0001) respectively. Eradication rates of 2nd line treatment LBTT were 55.8% and 60% by ITT and PP analysis. Higher side-effects were reported during the second line treatment. CONCLUSION H.pylori infection rate was high among the dyspeptic patients resulting chronic gastritis and atrophic change. H.pylori resistance rate to metronidazole and clarithromycin was high. Among 1st line therapies; the eradication rates of CBTT and ST were poor, while BBQT and Targeted therapy had a higher success rate. 2nd line therapy showed higher failure rate.

Background: Helicobacter pylori (H. pylori) is a gram-negative, microaerophilic bacterium that colonizes the human gastric mucosa, with an estimated global prevalence exceeding 50%. The increasing resistance of H. pylori to clarithromycin, a key antibiotic in eradication regimens, has led to a decline in the efficacy of standard treatment to below 80%. Consequently, international guidelines advocate for susceptibility-guided therapy to optimize treatment outcomes. Detection of clarithromycin resistance-associated mutations, including A2143G, A2142G, A2142C, and A2144G, is essential for improving therapeutic efficacy and mitigating the propagation of antimicrobial resistance. Aim: To evaluate the efficacy of tailored H. pylori eradication therapy based on clarithromycin resistance profiling. Materials and Methods: A total of 125 treatment-naïve patients diagnosed with H. pylori infection were enrolled in this study. The infection was confirmed through upper gastrointestinal endoscopy with histopathological analysis, the urea breath test, and stool antigen detection. Clarithromycin resistance-associated mutations were identified using polymerase chain reaction (PCR) analysis on gastric biopsy and stool samples. Based on the presence or absence of resistance mutations, patients were stratified into two treatment cohorts and received targeted eradication therapy. Treatment success was assessed 28 days post-therapy using a stool antigen test to confirm H. pylori eradication. Results: Among the 120 patients who met the inclusion criteria and completed treatment, 41.6% (n=50) were male, and 58.4% (n=70) were female, with a mean age of 39±9.1 years. Clarithromycin resistance-associated mutations were detected in 36 patients (30%), with A2143G identified in 35 cases (97.2%) and A2142G in 1 case (2.7%). In the clarithromycin-sensitive cohort, 84 patients underwent eradication therapy, and among the 60 who completed post-treatment assessment, the eradication rate was 91.6%. In the clarithromycin-resistant cohort, 36 patients received treatment, and among the 20 who completed post-treatment assessment, the eradication rate was 80% (p=0.038). Conclusion A substantial prevalence of clarithromycin resistance-associated mutations was observed among the study population. Susceptibility-guided eradication therapy demonstrated superior efficacy, with eradication rates exceeding 90%. These findings underscore the necessity of implementing resistance-based treatment strategies to optimize clinical outcomes and limit the further dissemination of antimicrobial resistance. Future investigations should focus on refining therapeutic approaches for H. pylori strains exhibiting clarithromycin resistance.

Backround Peutz–Jeghers (PJ) syndrome is a rare autosomal dominant disorder characterized by a mucocutaneous pigmentationon on oral mucosa and multiple hamartomatous polyps located in the digestive tract except esophagus. PJ syndrome can be diagnosed in early childhood by a characteristic pigmentation and family history of polyposis. However, it is often diagnosed first as a polyp in the small intestine that causes obstruction and intussusception and is often treated with a bowel resection. If diagnosed in young childhood, an effective non-invasive method is to resect the polyps by tying off the blood supply to the polyps, that is the method named ischemic polypectomy, before they grow to the point of obstruction using a endoscopy. PJ syndrome is rare in Mongolia, but in severe cases, small intestine polyps are treated only surgically. Double-balloon-endoscopy (DBE) has been performed at the Mongolian- Japanese Hospital since 2023, making it possible to diagnose and treat the syndrome endoscopically. Our patient, a 15-year-old boy, had a mucocutaneous pigmentation that had been previously undiagnosed and was first diagnosed with intussusception at the age of 13. He had undergone 4 endoscopic procedures for upper and lower gastrointestinal polyps at the National Center for Maternal and Child Health successfully. In our hospital, we found endoscopically multiple hamartomatous polyps of various sizes between 1-3 cm, and a 3 mm diameter tumor that filled 3/4 of the intestinal lumen was treated by ischemic polypectomy. After the procedure, there were no early or late complications related to the procedure. The child's condition improved, the main complaints subsided, and he continues his daily life normally. However, follow-up DBE is required.

Background: Small intestinal bacterial overgrowth (SIBO) is characterized by symptoms such as malabsorption, nutrient deficiencies, bloating, and abdominal pain. It can occur independently or in association with other gastrointestinal disorders. This study aims to determine the prevalence of SIBO in patients with digestive complaints, evaluate diagnostic outcomes, and analyze the composition and types of pathogenic bacteria present in the small intestine. Materials and Methods: A single-center, cross-sectional study was conducted at the Mongolian-Japanese Hospital, enrolling a total of 46 participants. SIBO was diagnosed using the hydrogen breath test (H₂BT) with lactulose/glucose as substrates. Among the 27 diagnosed cases, 5 patients were randomly selected for microbiological analysis of small intestinal contents. Results: SIBO was detected in 58.7% of the study participants. Among the 5 patients who underwent microbiological analysis, 80% (4/5) tested positive for pathogenic bacteria. The identified pathogens included: Gram-positive bacteria: Staphylococcus aureus (S. aureus); Gram-negative bacteria: Klebsiella pneumoniae (K. pneumoniae); Antibiotic-resistant bacteria: Methicillin-resistant Staphylococcus aureus (MRSA); Fungi: Candida albicans (C. albicans). The remaining 20% (1/5) had a baseline H₂BT value exceeding twice the standard threshold despite no detected pathogens. Conclusion SIBO is highly prevalent among patients with digestive complaints and may be associated not only with bacterial infections but also fungal overgrowth. Therefore, a multidisciplinary treatment approach, including antibiotics, dietary modifications, probiotics, and antifungal therapy, is necessary. While the hydrogen breath test is an effective diagnostic tool for SIBO, standardization of diagnostic protocols is required for improved accuracy.