This clinical trial studies the effect of sublimated mare milk supplement on gut microbiome of patients with acute bronchitis.

Food has a significant effect on the health of the body, the relationship between diet and health actualizes the importance of expanding the research of functional products. In mare's milk contains about 40 biological components necessary for the human body: amino acids, fats, enzymes (lysozyme, amylase), microelements (calcium, sodium, potassium, phosphorus, iron, magnesium, copper, iodine, sulfur, cobalt, zinc, bromine) and vitamins (A, C, B1, B2, B6, B12, E, H, PP, beta-carotene, folic acid) in optimally balanced proportions.

A high percentage of nutrients, including vitamins, amino acids, contribute to immunomodulation, increasing the adaptogenic properties of the body. Valiev A demonstrated the effect of the essential fatty acids of mare's milk on immunocompetent cells and non-specific resistance after 6 weeks from the beginning of inclusion in the ration of mare's milk.

Secretory IgA is the main immunoglobulin of mare's milk. The homology of human secretory IgA and mare's was previously demonstrated by cross-reactions using human anti-IgA antiserum.

The mare's milk has a powerful detoxification effect, the mare's microflora neutralizes the effect of mutagens, possesses, replenishes with the necessary complex of nutrients and removes toxins from the body. The milk has a certain degree of antimicrobial effect in relation to opportunistic and pathogenic fungi, bacteria and viruses due to its own microflora.

The mare's milk is rich in active substances, natural enzymes that help regulate intestinal flora, limiting the growth of unwanted bacteria and increasing the growth of bifidobacteria and lactic acid bacteria.

In addition, the composition of mare's milk provided immunoglobulins A, M and G, which act as a marker of those microorganisms that can be pathogenic, which facilitates the protection task.

The high antimicrobial activity of mare's milk is associated with the lysozyme contained in it, immunoglobulins, lactoperoxidase and lactoferrin. Getting into the digestive tract lysozyme has a powerful normalizing effect on the composition of the microbial flora of the mouth and intestines. Lysozyme of breast milk is 100 times more active than lysozyme of cow's milk. It not only inhibits the growth of pathogenic flora, but also promotes the growth of bifidoflora in the intestines of infants.

In the framework of the project, methods for the restoration of the mucos layer of the intestine after antibiotic therapy will be developed. In order to develop the algorithm, preliminary studies will be made of changes in the structure of the intestinal microbiota after antibiotic therapy. Recruiting of patients with infectious / non-infectious pathology is supposed, clinical and laboratory examination, biomaterial sampling during antibiotic therapy, 1-5 days and 1-60 days after completion will be performed. Along with the study of microflora, local immunity studies will be carried out. To study the fundamental foundations, experimental studies will be carried out on laboratory animals. On the basis of the knowledge obtained, an algorithm for the restoration of the mucinous layer of the intestine after antibiotic therapy will be published in the form of methodological recommendations.

Inclusion Criteria:

• Patients of both sexes aged 4-5 years
• The voluntary informed consent of the parent to participate in the study
• Established diagnosis of acute upper respiratory tract disease with prescription of antibacterial therapy
• The duration of symptoms of acute upper respiratory tract disease no more than 72 hours
• Lack of prescription of antibacterial drugs in the last 3 months

Exclusion Criteria:

• Severe forms of acute infections
• The presence in the history of taking probiotics and antibiotics for three months before admission to hospital
• Presence in the anamnesis of chronic diseases of the digestive tract, and also of any surgeries on the digestive tract
• The presence of severe concomitant diseases of the kidneys, liver, cardiovascular, respiratory and other body systems, cancer, mental and decompensated endocrine diseases, tuberculosis, HIV infection
• Patient involvement in other clinical trials within the last 3 months
• Lack of willingness of the patient to cooperate with the doctor-researcher