The problem of antibiotic resistance is more relevant than ever. The crisis associated with the spread of resistance to antibiotics is approaching every day. New antibacterial drugs and methods that allow for effective combating of resistant microorganisms are not emerging, therefore posing a serious challenge to humanity, as the effectiveness of antibiotics directly impacts important areas of human life such as medicine and agriculture. Purpose. The article provides a systematic view of the phenomenon of antibiotic resistance. Materials and methods.To analyze the literature, materials from the PubMed and PubMed Central resources of the US National Library of Medicine, Google Scholar, Elsevier Clinical Key and Elsevier Science Direct. The sample consisted of scientific papers devoted to antibiotic resistance. Results.The article reveals the causes of emergence, mechanisms, rate of development, pathways of spread of antibiotic resistance and consequences of acquiring resistance for microorganisms and methods of containing antibiotic resistance.

Purpose: Immunodeficiency conditions, which are characterized by reduced immune activity that promotes the development of chronic diseases, are needed for efficient monitoring. A promising area of monitoring and early diagnosis of immunodeficiency diseases is the determination of metabolic biomarkers in the blood. Methods: In this work, we identified a set of lipid biomarkers of immunodeficiency states by performing high-performance liquid chromatography–high-resolution mass spectrometry (HPLC-HRMS) analysis of blood plasma samples from mice and processing them with bioinformatics approaches. Potential biomarkers were selected through statistical analysis and further validated by MS/MS. Conclusions: As a result, 15 lipids were confirmed and selected as potential biomarkers of immunodeficiency states. The selected biomarkers can be further studied and serve as promising targets for the early diagnosis of immunodeficiency diseases.

Betulin, a lupane-type triterpenoid, is of growing interest as an active component of veterinary and feed formulations. For such complex matrices, robust and traceable analytical methods are required to control the betulin content and ensure product quality. In this work, a simple and rapid reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the quantitative determination of betulin in an oil-in-water emulsion-based feed additive. Chromatographic separation was performed on a C18 column using an acetonitrile–water (80:20, v/v) mobile phase in the isocratic mode at 35 °C, with a flow rate of 0.35 mL/min and UV detection at 210 nm; the total run time does not exceed 3 min. Quantification was carried out by external calibration using a certified betulin reference over the concentration range relevant to the declared product content. The method was validated in accordance with national metrological guidelines with respect to selectivity, linearity, accuracy, precision, range, and robustness. The results demonstrate excellent linearity, satisfactory precision, and recoveries close to 100%, as well as the absence of matrix interferences. The developed RP-HPLC procedure is suitable for routine quality control of the novel feed additive and can be adapted to other betulin-containing products.