The study presents and evaluates an automated system for simulating the porcine gastrointestinal tract (AGIT), comprising functionally distinct modules corresponding to the small and large intestine, with controlled pH, temperature, anaerobic conditions, and continuous supply of an artificial intestinal medium. The system was inoculated with native intestinal content samples from pigs, in which both culture-based methods and quantitative PCR confirmed that the microbiota composition corresponded to physiological norms, indicating the validity of the initial inoculum. Stabilization of microbiological parameters was achieved on days 7–8 and maintained throughout the entire observation period up to 21 days, indicating the formation of a stable microbial community. Phenotypic dynamics of antibiotic susceptibility were observed in E. coli and Enterococcus spp . isolates obtained from native material and after 21 days of cultivation in the system. Genetic analysis revealed a high prevalence of antibiotic resistance genes and integrons: in E. coli , 100% for intI1, blaCTX-M, sul2, and tetO ; in enterococci, 100% for intI1 and 90% for tetO . The developed AGIT model demonstrates microbiota and resistance dynamics comparable to in vivo conditions and may be used for assessing microbiological risks.
Objective: to assess the dynamics of HIV testing coverage, the structure of surveyed populations, and the frequency of detection of HIV markers among the population of Southern Russia. Materials and methods: the analysis of data from federal statistical observation form No. 4 ≪Information on the results of blood tests for HIV antibodies≫ for 2020–2025 was carried out for 15 constituent entities of the Russian Federation, which are part of the Southern and North Caucasus Federal Districts. Results: in the South of Russia, the coverage of HIV screening has increased annually since 2020 and amounted to 34% by 2026. In contrast, the frequency of HIV infection detection decreased by 1.7 times. A significant reduction in the risk-based nature of HIV serological screening was noted, as the proportion of individuals from the most vulnerable groups in the Southern and North Caucasian Federal Districts surveyed with respect to HIV infection was only 2.0Ѓ}0.04% and 1.4Ѓ}0.05%, respectively. However, the HIV detection rate in these population groups is significantly higher than in the general population. Conclusion: targeted risk-based selection of population groups for HIV serological screening is strategically important for ensuring early diagnosis of HIV infection.
Hibernation induces significant physiological changes in mammals, including suppressed immune responses, metabolic downregulation, and shifts in gut microbiota activity. This study examined seasonal variation in the functional properties of gut microbiota in Nyctalus noctula by assessing the genotoxic and oxidative effects of microbial metabolites using lux-biosensor assays based on Escherichia coli strains carrying stress-inducible promoters: PrecA for detecting DNA damage responses and PkatG for oxidative stress responses. Fifty-eight microbial isolates were obtained from fecal samples collected during hibernation (n = 26) and active (n = 32) periods and evaluated for mutagenic, DNA-protective, antioxidant, and prooxidant activities. Metabolites from isolates collected during hibernation exhibited significantly stronger DNA-protective effects compared to those from active bats, while oxidative stress modulation did not differ significantly between the two groups. A significant negative correlation was observed between bacterial abundance and antioxidant responses, suggesting a possible link between microbial density and functional activity. These results indicate that the physiological state of the host influences the functional output of gut microbiota, particularly in relation to DNA protection. The findings enhance our understanding of seasonal microbiome–host interactions in bats and underscore the relevance of microbial metabolites in shaping host stress responses during hibernation.
Regional HIV-1 epidemics are evolving with distinct patterns in transmission routes, subtype distribution, and molecular transmission cluster (MTCs) characteristics. We analyzed 9500 HIV-1 cases diagnosed over 30 years using phylogenetic and network methods, integrating molecular, epidemiological, demographic, and behavioral data. Subtype A6 remains dominant nationally (80.6%), followed by 63_02A6 (7.9%), subtype B (5.6%), 02_AGFSU (1.2%), 03_A6B (0.7%), and 14/73_BG (0.6%). Non-A6 infections were more common among males (OR 1.51) and men who have sex with men (OR 7.33). Network analysis identified 421 MTCs, with 256 active clusters. Clustering was more likely among young individuals (OR: 1.31), those not receiving antiretroviral therapy (OR: 2.70), and injecting drug users (OR: 1.28). Non-A6 subtypes showed a higher likelihood of clustering. Phylogenetic analysis revealed that local clusters of the major subtypes originated between the late 1970s (subtype B) and the mid-2000s (63_02A6) with links to populations in Eastern Europe, Central Asia (subtypes A6, 63_02A6, 02_AGFSU, 03_A6B), and Western Europe and the Americas (subtype B, 14/73_BG). These findings indicate a complex, evolving regional epidemic transitioning from subtype A6 dominance to a more diverse mix of subtypes. The ability of non-A6 subtypes to form active MTCs suggests their establishment in the local population.
Introduction. The relevance of this study is due to sanitary and hygienic risks associated with anthropogenic pollution of surface waters, especially in sanitary protection zones (SPZ) of drinking water sources. Disruption of the thermal regime of water bodies promotes the growth of pathogenic microflora. The use of infrared thermography as a remote monitoring method can significantly improve the efficiency of sanitary and hygienic water monitoring.Objective. To substantiate and test a method for detecting unauthorized wastewater discharge into surface watercourses using thermal imaging equipment with subsequent bacteriological verification.Materials and methods. The study used thermograms and water samples from the coastal zone of the Don River within sanitary protection zones (SPZ) boundaries. Thermal imaging was conducted using portable and remote devices, including the Doogee V20 Pro (InfiRay) and DJI Mavic 3 Thermal. Bacteriological analysis (total coliforms, Escherichia coli, Enterococcus faecalis) was carried out in accordance with MU 4.2.3690–21, while sample transport and storage followed GOST R 59024–2020. Statistical analysis was performed using Student’s t-test (p < 0.05).Results. Thermal inspection of the Don River delta revealed coastal areas where water temperature exceeded background levels by ≥3 °C. These locations showed more than fivefold exceedances of total coliforms, E. coli, and E. faecalis concentrations. The calculated expanded uncertainty (±0.85 °C, p = 95%) confirmed the reliability of these differences. A correlation was found between thermal anomalies and microbiological indicators, indicating two likely sources of unauthorized discharge.Limitations. The developed approach allows identifying potential sources of unauthorized wastewater discharge into surface waters associated with sanitary and bacteriological exceeds.Conclusion. The practical value of infrared thermography has been confirmed by field studies. The method proved effective as an auxiliary tool for the rapid detection of unauthorized discharges and enhancing the effectiveness of sanitary and hygienic water monitoring.Compliance with ethical standards. The study did not require approval from a biomedical ethics committee or other documentation.Contributions: Kalyuzhin A.S. – study design, data analysis, manuscript writing, manuscript editing; Morozova M.A. – study design, manuscript editing; Zamaraev V.S. – manuscript editing; Sinitsyna O.O. – data analysis, manuscript writing, manuscript editing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.Conflict of interest. The authors declare no conflict of interest.Funding. The study had no sponsorship.Received: June 17, 2025 / Revised: July 22, 2025 / Accepted: October 15, 2025 / Published: November 14, 2025
