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In the modern world, infections caused by multidrug-resistant (MDR) bacteria have become carriers of global threats to human health. Today these pathogenic bacteria have come to be referred to as "superbugs" and their number and aggressiveness is growing. This group of "superbugs" also includes Staphylococcus aureus. It is capable of infecting almost any tissue in the human body. Therefore, it became necessary to find alternative antibiotic methods of treating bacterial infections. The use of bacteriophages is again among them. We propose a new approach in the search for strain-specific (target) phages through the structures of the CRISPR/Cas-systems of bacteria. As is known, CRISPR/Cas systems are the most ancient system of "adaptive immunity" in bacteria. This system makes bacteria resistant to phages and plasmids. This approach is based on the use of methods of structural genomics and software bioinformatics modeling. Using them, an algorithm was developed to search for the structures of CRISPR/Cas systems in bacterial genomes presented in the NCBI databases and screening through their CRISPR cassettes of phages with which a particular strain could meet. The design of the developed algorithm was tested on the genome of methicillin-resistant S. aureus strain (ST228-MRSA-I) from the GenBank database. The results of the search for loci and structures of the CRISPR/Cas system in the genome of this strain showed that the identified system belongs to type III-A. It was found that the cas genes and the CRISPR cassette are located at a distance from each other and between them are located several genes that perform other functions in the genome of the S. aureus strain. It was shown that the structures of spacers in the detected CRISPR cassette are identical to protospacers of phages, the hosts of which are bacteria of the following genera – Staphylococcus, Mycobacterium, Streptococcus, Bacillus, Gordonia, Arthrobacter, Streptomyces. Thus, it can be stated that the developed algorithm of software methods for searching for loci of CRISPR/Cas systems and screening for phages makes it possible to type both the system itself and through its spacers to detect and identify phage races with which a particular bacterial strain could meet. The degree of resistance of a particular bacterial strain to specific phages is also determined, which in the long term should ensure the effectiveness of targeted phage therapy for infections caused by pathogenic bacteria, including "superbugs".

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Due to the rich chemical composition of Siberian larch (Larix sibirica Ledeb), its products are widely used in medicine, pharmacology, agriculture, perfumery and cosmetics industry. Larch wood and bark contain a large amount of low molecular weight substances with high biological activity, namely: essential oils, ascorbic acid, tannins, anthocyanins, flavonoids, organic acids. The most important and useful of them are flavonoids due to their significant content in raw materials such compounds as: dihydroquercetin (DHA), arabinogalactan (AG), quercetin (QU), ardixin (ARD). On the basis of dihydroquercetin, preparations for the treatment and prevention of atherosclerosis, capillary-strengthening agents, anti-allergic drugs are created, and due to the high ability to complex formation, it actively removes heavy metals, including radionuclides, from the body. The main experimentally established properties of AG are immunomodulatory and antioxidant effects. In the diet, there is often a deficiency of dietary fiber needed by the human body. Quercetin is a powerful antioxidant that increases the body's resistance to radiation and a food antioxidant. It can also enhance antiinflammatory, antiviral, and immunoprotective effects. Ardiksin is a nanobiocomposite containing no. more than 95.0% of the natural polysaccharide arabinogalactan and no. less than 5% of the bioflavonoid dihydroquercetin. The biological activity of ardixin has shown its effectiveness in the treatment of oncological diseases as a concomitant agent during radiation and chemotherapy. Based on the significant importance of these polysaccharide compounds in the creation of new functional food products and therapeutic agents for medicine, in this study, the goal was to identify the effect of stimulating the growth of the commercial probiotic preparation Bifidobacterium bifidum when cultivated on media with polysaccharide compounds: purified arabinogalactan, dihydroquercetin, quercetin, ardixin. These polysaccharide compounds are processed products of Siberian larch (Larix sibirica Ledeb). In the course of a study on the evaluation of growth stimulation of B. bifidum by polysaccharides: AG-purified, DHA, QU, ADC, it was found that: 1) growth of B. bifidum is most effective in a medium with DHA; 2) when growing on a medium with AG-clean. there is almost five times less growth stimulation compared to DHA; 3) the smallest growth of B. bifidum is observed in the medium with QU, which is more than 208 times less than its growth on the medium with DHA.