Background: Allergic and atrophic forms of chronic rhinitis are common among the population, characterized by a chronic progressive course with a tendency toward increasing prevalence. Worldwide, allergic rhinitis affects approximately 10–40% of adults and 2–25% of children. According to a study conducted in Mongolia, the prevalence of allergic rhinitis among adults in Ulaanbaatar was reported to be 23.6%, with an increasing trend anticipated in the future. In allergic and atrophic rhinitis, structural alterations occur in the nasal mucosa, including disruption of the normal architecture of the pseudostratified epithelium and ciliated cells, accompanied by changes in goblet cell number and dysfunction of their activity, resulting in a complex pathological process. In otorhinolaryngology practice in Mongolia, there is a relative lack of studies investigating the ultrastructural changes of the nasal mucosa in allergic and atrophic rhinitis. Aim: To compare ultrastructural and histological changes of the nasal mucosa in allergic and atrophic rhinitis. Materials and Methods: Ethical approval was obtained from the Research Ethics Review Committee of the Mongolian National University of Medical Sciences at the meeting held on April 24, 2020 (Protocol No. 2020/З-04). Appropriate ethical permission was also obtained from the EMJJ ENT Hospital. Nasal mucosal tissue samples were collected from surgically resected specimens of patients aged 20–45 years diagnosed with allergic and atrophic rhinitis. The mucosal specimens were processed at the Institute of Biomedical Sciences of the Mongolian National University of Medical Sciences. Samples were fixed and dehydrated according to the protocol, coated with 100 Å gold, and examined using a scanning electron microscope (FEI Quanta FEG 250, USA). In addition, paraffin blocks were prepared, sectioned at 4 μm thickness, stained with Hematoxylin and Eosin, and analyzed histologically. Results: In allergic rhinitis, the pseudostratified epithelium was relatively preserved; however, disorganization of ciliated cells, partial loss of cilia, and goblet cell hyperplasia were observed. In contrast, atrophic rhinitis showed epithelial thinning, near-complete loss of ciliated structures, glandular atrophy, and submucosal fibrosis. Conclusion Allergic rhinitis is associated with relatively mild and predominantly functional mucosal alterations, whereas atrophic rhinitis demonstrates severe structural damage with irreversible impairment of mucosal protective function.

Staphylococcus aureus (S. aureus) is a clinically significant pathogen widely distributed in food production environments. Its ability to form biofilms on food contact surfaces enhances 50 environmental persistence, increases antibiotic resistance 10–1500-fold, and poses serious challenges for food safety and public health. In Mongolia, data on the biofilm-forming ability of S. aureus in meat processing and retail environments are limited. A cross-sectional study was conducted on 437 samples collected from meat supply and retail sites, including raw meat, aprons, counters, trolleys, and workers’ hands. Isolation and confirmation of S. aureus were performed using MNS 6308:2012 and ISO 6888-1:2021 standards, followed by PCR amplification of the species-specific nucA gene (270 bp). Biofilm formation was evaluated using the microtiter plate assay with 0.5% glucose supplemented tryptic soy broth and optical density at 490 nm, and confirmed by scanning electron microscopy (SEM). Statistical analyses were performed using chi-square tests with p< 0.05 considered significant. Of the 437 samples, 14.2% (62/437) were contaminated with S. aureus. Contamination was higher in retail markets (25.9%) than supply sites (9.3%). Among isolates, 40.3% exhibited biofilm-forming ability: 29.0% weak, 9.7% moderate, and 1.6% strong. Biofilm formation did not significantly differ by sampling site or sample type (p>0.05). SEM imaging revealed distinct biofilm architectures with polysaccharide matrices at 80,000× magnification. A considerable proportion of S. aureus isolates from meat processing and retail environments exhibited biofilm forming ability, posing a potential risk for cross-contamination and persistent foodborne transmission. Strengthened hygiene and sanitation measures are essential to control biofilm-associated S. aureus contamination in Mongolia’s meat production and supply chain.