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.

Background: Helicobacter pylori (H.pylori) infection is highly prevalent worldwide, with an overall infection rate of 50% of the total population. Effective and accurate eradication treatment for H.pylori is considered one of the most important preventative measures against gastric cancer. However, the increasing prevalence of clarithromycin-resistant H. pylori strains has significantly compromised the success rates of standard eradication regimens. In recent years, many countries have adopted molecular diagnostic methods to detect H.pylori infection and assess clarithromycin resistance. These approaches, which are often non-invasive, enhance both diagnostic accuracy and the ability to tailor treatment strategies. Although numerous studies have investigated methods for detecting H. pylori and clarithromycin resistance using gastric tissue specimens, relatively few have focused on the clinical application of stool-based diagnostics, despite their potential advantages in non-invasive testing. Aim: To detect H.pylori infection and clarithromycin resistance using molecular biological methods from both gastric tissue and stool samples, and to comparatively evaluate the diagnostic outcomes. Materials and Methods: The hospital-based cross-sectional study was conducted at the Gastroenterology department of the Mongolia-Japan Hospital. A total of 125 dyspeptic patients aged 18-80 years were enrolled. Eligibility criteria required the H.pylori infection to be confirmed by at least two diagnostic methods. Each participant underwent both invasive (histological examination, gastric biopsy-based real-time PCR) and non-invasive (urea breath test, stool antigen test, stool-based real-time PCR) methods. Gastric biopsies and stool samples were analyzed by real-time PCR to detect H.pylori and identify clarithromycin resistance-associated 23S rRNA point mutations (A2143G, A2142G, A2142C) Results: Among the study participants, 60.0% (n=75) were female and 40.0% (n=50) were male, with a mean age of 39±1 years. Comparative evaluation of the diagnostic methods for H.pylori infection demonstrated that the stool antigen test, performed in 104 individuals, yielded positive results in 91 cases (87.5%), whereas the urea breath test, performed in 51 individuals, was positive in 45 cases (88.2%). Using real-time polymerase chain reaction (PCR), H.pylori was detected in 76 of 101 stool samples (75.2%) collected in ENAT transport medium, and in 43 of 87 raw stool samples (49.4%). The estimated diagnostic sensitivities were 94% for the urea breath test, 91% for the stool antigen test, 78% for real-time PCR using ENAT-preserved stool, and 49% for real-time PCR using raw stool specimens. Clarithromycin resistance was found in 36 participants (28.8%), while 89 participants (71.2%) carried H.pylori strains susceptible to clarithromycin. Clarithromycin resistance was detected in 27.6% of stool samples and 30.5% of gastric biopsy specimens. Among the clarithromycin-resistant isolates identified from gastric tissue, 35 cases (97.2%) carried the A2143G point mutation, while the A2142G mutation was detected in only 1 case (2.8%). All resistant cases detected from stool samples carried the A2143G mutation, whereas the A2142G mutation was not observed. Conclusion Real-time PCR demonstrated high efficacy for the detection of H.pylori infection and clarithromycin resistance in gastric biopsy specimens. While the sensitivity of stool-based real-time PCR was comparatively lower, detection rates improved with the use of ENAT transport medium. These findings highlight the potential of stool-based real-time PCR as a non-invasive diagnostic tool; however, further investigations are warranted to optimize assay performance through rigorous standardization and refinement of sample processing protocols for the accurate detection of clarithromycin-resistant H.pylori.

Background: Respiratory viral and bacterial infections are one of the leading causes of hospitalization and death worldwide, particularly affecting children, the elderly, and immune compromised individuals. The detection of causative pathogens is crucial for understanding the epidemiology, prevention, management, and treatment of severe pneumonia. Molecular diagnostic methods provide high sensitivity and speed, enabling the simultaneous detection of viral and bacterial co-infections. Aim: Detection of single and combined viral and bacterial infections in hospitalized children with pneumonia using multiplex PCR. Materials and Methods: We conducted a cross-sectional study design involving 100 hospitalized participants at the National Center for Mothers, Newborns, and Women II. The study utilized questionnaires and laboratory analysis methods. Nasopharyngeal swabs were collected from the participants using a sterile swab and transported in a UTM transport medium (Jiangsu, China). After nucleic acid extraction using the STARMag 96 ProPrepC assay, the samples were analyzed with the Seeprep 32 automated analyzer (Seegene Inc., Korea). Real-time polymerase chain reaction (PCR) analysis was performed using the Allplex™ RV Master Assay and Allplex™ PneumoBacter Assay (Seegene Inc., Korea), with the CFX-96 system (BioRad Inc., USA). Results: The prevalence of viral infections in the study population was as follows: influenza type A 3% (n=3), influenza type B 3% (n=3), total influenza virus 14% (n=14), respiratory syncytial virus 18% (n=18), adenovirus 10% (n=10), rhinovirus 20% (n=20), and SARS-CoV-2 5% (n=5). No bacterial infections, such as B.parapertussis or L.pneumophila, were detected. However, bacterial infections identified included B.pertussis in 1% (n=1), C.pneumoniae in 2% (n=2), H.influenzae in 43% (n=43), M.pneumoniae in 52% (n=52), and S.pneumoniae in 45% (n=45). Of the 100 children in the study, 6% had influenza or influenza-like illness. Among these, 43% had the virus alone, and 14% had a viral co-infection. Bacterial infections were detected individually in 40% of cases, with co-infections in 46% of bacterial cases. Conclusion Metapneumovirus, B.parapertussis, and Legionella pneumophila were not detected in the study participants (0%). Among the viral infections, respiratory syncytial virus (18%, n=18) and rhinovirus (20%, n=20) had the highest prevalence. For bacterial infections, H.influenzae (43%, n=43), M.pneumoniae (52%, n=52), and S.pneumoniae (45%, n=45) were most commonly detected.

Background: Approximately 30–50% of cases of severe oligozoospermia and non-obstructive azoospermia are attributed to genetic factors, as determined through semen analysis. Microdeletions in the AZF (Azoospermic Factor) region of the Y chromosome represent one of the genetic causes of male infertility. The European Academy of Andrology (EAA) recommends screening for AZF microdeletions in men diagnosed with azoospermia or severe oligozoospermia. Folate metabolism plays a crucial role in spermatogenesis and germ cell development. Polymorphisms in genes involved in this metabolic pathway such as MTHFR, MTR, and MTRR have been implicated in the pathogenesis of oligozoospermia and azoospermia. The reason for conducting this research was lack of studies investigating the in Mongolia have concurrently investigated the association between AZF microdeletions on the Y chromosome and the presence of MTHFR 677C>T and 1298A>C, MTR 2756A>G, and MTRR 66A>G polymorphisms in men with severe oligozoospermia or non-obstructive azoospermia. Aim: To determine the presence of Y chromosome AZF microdeletions, as well as the MTHFR 677C>T and 1298A>C, MTR 2756A>G, and MTRR 66A>G polymorphisms in men with severe oligozoospermia and non-obstructive azoospermia Materials and Methods: This study was conducted at the Clinical Molecular Diagnostics Center of the Mongolian National University of Medical Sciences (MNUMS). Peripheral blood samples were collected from all study participants, and genomic DNA was extracted using the “PROBA-RAPID Genetika” DNA extraction kit manufactured by DNA-Technology LLC (Russian Federation). Thirteen AZF microdeletions (sY84, sY86, sY127, sY134, sY142, sY242, sY254, sY255, sY615, sY1125, sY1197, sY1206, sY1291) were detected using the “AZF Microdeletions REAL-TIME PCR Genotyping Kit.” Polymorphisms in the MTHFR gene (677C>T and 1298A>C), the MTR gene (2756A>G), and the MTRR gene (66A>G) were identified using the “Folate Metabolism REAL-TIME PCR Genotyping Kit.” Results: A total of 11 men aged between 18 and 44 years who had been diagnosed with severe oligozoospermia or non-obstructive azoospermia based on repeated semen analyses (two or more times) were included in this study. Among participants with severe oligozoospermia or non-obstructive azoospermia, AZF microdeletion analysis of the Y chromosome revealed one case with an sY1291 (AZFc) microdeletion and another case with an sY1197 (AZFc) microdeletion. No AZF microdeletions were detected in the remaining participants. Regarding the MTHFR 677C>T polymorphism, the homozygous wild-type CC genotype was observed in 55% (6), the heterozygous CT genotype in 18% (2), and the homozygous mutant TT genotype in 27% (3). The frequency of the C allele was 64% (14), while the risk-associated T allele was 36% (8). For the MTHFR 1298A>C polymorphism, the homozygous AA genotype was found in 64% (7), the heterozygous AC genotype in 27% (3), and the homozygous CC genotype in 9% (1). The A allele frequency was 81% (17), and the risk-associated C allele frequency was 19% (4). In the case of the MTR 2756A>G polymorphism, 64% (7) of participants had the AA genotype, and 36% (4) had the AG genotype. The GG genotype was not detected. The A allele frequency was 82% (18), and the risk-associated G allele frequency was 18% (4). For the MTRR A66G polymorphism, the AA genotype was observed in 36% (4), and the AG genotype in 64% (7). The GG genotype was not detected. The A allele frequency was 68% (15), and the risk-associated G allele frequency was 32% (7). Conclusion In this study, Y chromosome AZF microdeletions were detected in 18% of participants with severe oligozoospermia or non-obstructive azoospermia, which is considered relatively low. In such cases, identifying polymorphisms in the MTHFR, MTR, and MTRR genes becomes important. Disruptions in folate metabolism caused by these polymorphisms can lead to elevated homocysteine levels. Supplementation with activated folate (5-MTHF) has been shown to help maintain normal plasma homocysteine concentrations, which may be beneficial in individuals with impaired folate metabolism.

Background: To prevent and combat the spread of the COVID-19 pandemic, the Government of Mongolia has implemented measures such as movement and time restrictions, social distancing and isolation, closure of schools, kindergartens and public places, immunization, and others. It has caused adverse consequences for people, social relations, and the economy, causing health, social, economic, and humanitarian crises. Not only does this situation, medical students, as frontline healthcare workers, are more susceptible to virus infection. Vaccines against COVID-19 have been researched quickly due to the pandemic and are being used under emergency use authorization. In our country the approach of mixing vaccine doses from different manufacturers was used (fractional doses). Therefore, there is no study on the exposure of medical students to the COVID-19 infection and the adverse effects after receiving a dose of a heterologous vaccine. Objective: To study the exposure to the COVID-19 infection and vaccination status of medical students. Methods: The survey was conducted from November 2023 to December 2023 using a cross-sectional study design, and 170 students who study at ASUSU and live in the dormitory were included. Results: A total of 170 students participated in the study. 55.9% (n=95) of them were in the first year, 22.4% (n=38) were in the second year, 10% (n=17) were in the third year, 7.6% (n=13) were in the fourth year, 2.4% (n=4) were from the 5th year and 1.8% (n=3) were from the 6th year students. 88.2% (n=150) of students were female and 11.8% (n=20) were male. In this study, 37.1% of the students were infected by COVID-19 infection previously. Among them, 50% of the students were infected from family members, 16.7% from the school environment, and 15.2% did not know about the source of infection. 76.2% of the respondents were diagnosed with COVID-19 in a medical institution, and forty-one students answered that they were treated at the hospital. 83% of the cases were treated at home and were cured within 14 days. In contrast, 93.8% of the hospitalized students were treated within four months to 1 year. The current study demonstrates neurological, respiratory, sensory, cardiovascular, psychiatric, digestive, and dermatological symptoms were in 37.6%, 24.1%, 27.6%, 17.6%, 11.8%, 11.2%, and 10% of the students who participated in the study, respectively. For a year or more, symptoms of all organ systems were present, but neurological symptoms appeared to be the highest. 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine, 3.5% (n=6) did not receive the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects and 65% (n=106) had no side effects. Conclusion In this study, 37.1% of the students were infected by COVID-19 infection previously. According to the current study, symptoms related to the nervous system was the most prevalent and 55.9% (n=115) of the enrolled students received 3 or 4 doses of the vaccine. In total, 35% (n=60) of the enrolled students experienced side effects.

Acinetobacter baumannii is considered to be a worldwide threat to public health due to its high antimicrobial resistance rates and the severe infections it can cause. Little is known about this pathogen’s resistance in Mongolia. This report aims to describe the antimicrobial resistance profile of A. baumannii at a tertiary hospital in Mongolia. The cross-sectional analysis was conducted at the tertiary care laboratory hospital in the First Central Hospital of Mongolia from 2013.01 to 2013.12 and from 2020.01 to 2020.12.
A total of 141 in 2013, 227 in 2020 consecutive microbiological reports were analyzed. A. baumannii was isolated. Epidemiological and microbiological data, including the isolation setting and patient information, were recorded. Prevalence of multi-drug and extensive-drug resistance was assessed according to international standards.
The median age of individuals was 22 years (2 – 35 years); female was the predominant gender (53%). The hospital’s intensive care units had the highest number of isolates (n = 226). The most frequent specimen from which A. baumannii was isolated was secretion of respiratory tract (n = 119). Resistance to carbapenems was reported to be 35% among the isolates (n = 115) in 2013 and 74.69% (n=135) respectively. This report reveals the threat of this pathogen to public health in Mongolia and appeals for antibiotic stewardship programs throughout all tertiary hospitals and other hospitals.

Introduction: Base excision repair (BER) is mainly responsible for the correction of small base changes of DNA damage. BER pathway involved many enzymes including OGG1 and XRCC1. The defective DNA repair is associated with an increased risk of various cancers including hematologic malignancies-leukemia and myelodysplastic syndrome (MDS). However, it is deniably these polymorphisms alter the susceptibility and clinical outcome of MDS patients. The aim: This study was to evaluate the impact of polymorphisms in gene encoding one protein of BER system: XRCC1 Arg399Gln in MDS and healthy population. Methods: In this study, we recruited 60 health control group [median 47.9 years, 9 MDS subjects [median 56.6 years] were included in this study. Genotyping was carried out by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Allele and genotype frequencies were calculated by direct counting. Result: The frequencies of genotypes of XRCC1 Arg399Gln were as follows: Arg /Arg 1 (11%), Arg/Gln 6 (66%), Gln/Gln 2 (22%) in MDS and Arg /Arg 18.4%, Arg/Gln40%, Gln/Gln41.6% in health control for XRCC1 Arg399Gln. The result revealed that genotypes Arg399Gln increased the risk of MDS In conclusion this study is the first to analyze XRCC1 SNPs and their associated risk of MDS in Mongolian samples. To fully understand the role of DNA damage and DNA repair in the MDS, prospective studies are needed and other genes (OGG1 Ser326Cys, MUTYH Gln324His, APE Asp148Glu) of base excision repair pathway should be analyzed.