The article presents a study of the qualitative and quantitative structure of etiologically significant microorganisms received from patients with nosocomial sinusitis from intensive care units of multiprofile and infectious diseases hospitals. OBJECTIVE:To evaluate the qualitative and quantitative composition of the causative agents of nosocomial sinusitis and their sensitivity to antibacterial chemotherapy drugs in modern conditions. MATERIAL AND METHODS:During the period 2022-2023, we selected 45 patients from 6 ICU based on a multidisciplinary hospital and 11 patients from the ICU based on an infectious profile hospital, who were diagnosed with nosocomial sinusitis based on anamnesis, clinical picture, and computed tomography results. The qualitative and quantitative composition of microorganisms in the discharge obtained during therapeutic and diagnostic puncture of the maxillary sinuses in all patients was studied. RESULTS:According to the results it was revealed that in the multidisciplinary hospital the following microorganisms were the most frequently detected in patients with nosocomial sinusitis: Klebsiella pneumoniae, Acinetobacter baumannii, Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus haemolyticus, Enterococcus faecium, Enterococcus faecalis, Ochrobactrum anthropi. In patients with nosocomial sinusitis in the infectious diseases hospital the most frequently isolated were Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Proteus mirabilis. Fungal microorganisms were isolated much less frequently than bacterial microorganisms in both hospitals and were represented only by Candida albicans. In the multiprofile hospital the isolated strains of bacterial microorganisms were characterized by multidrug resistance in 89% of cases, and in the infectious diseases hospital - in 91% of cases. CONCLUSION:In the treatment of patients with nosocomial sinusitis, it is necessary to adjust empirical antibiotic therapy based on individual results of a bacteriological study. In case of ineffectiveness of antibacterial therapy, it is possible to use personalized biotherapy with virulent bacteriophage preparations in addition to prescribed antibacterial chemotherapy drugs, which makes it possible to enhance the antimicrobial effect of the therapy due to the additive action of drugs of two groups.

OBJECTIVE:To compare the microbiota of the oropharynx in healthy children and children with acute tonsillitis and pharyngitis. MATERIAL AND METHODS:The study included two groups of patients (139 people) aged from 1 year to 17 years inclusive. The main group consisted of children with acute tonsillitis and acute pharyngitis (111 patients, average age 7±4 years), the control group consisted of 28 healthy children (average age 7±6 years) without signs of upper respiratory tract infection. All patients were examined and material was taken from the mucous membrane of the posterior pharyngeal wall and palatine tonsils, the samples obtained were subjected to bacteriological examination to isolate a pure culture and identify bacterial microorganisms and virological examination by polymerase chain reaction in order to isolate a number of typical respiratory viruses and herpes viruses. RESULTS:It was found that viral-bacterial associations predominate (66.7%) in patients with acute tonsillitis and pharyngitis (32% in healthy volunteers). The detection rates of typical respiratory viruses and herpes viruses in patients with acute tonsillitis and pharyngitis are comparable (44% and 40.5%, respectively). Streptococcus pyogenes (beta-hemolytic streptococcus group A, 6.3%), as well as Streptococcus pneumoniae, Moraxella catarrhalis, Klebsiella pneumoniae and Pseudomonas aeruginosa were detected only in patients with acute tonsillitis. Other microorganisms were isolated both in healthy patients and in children with acute tonsillitis and pharyngitis, but in the presence of inflammatory changes in the pharynx, the concentration of microorganisms was slightly higher than in a healthy state, which is especially significant for Staphylococcus aureus. In patients without signs of inflammation, typical respiratory viruses (rhinovirus, 14%) and herpes viruses (with a predominance of type 6 herpes virus - 28%) were also found in a percentage comparable to that of patients with acute tonsillitis and pharyngitis. CONCLUSION:The etiology of acute tonsillitis and pharyngitis in children is dominated by viral-bacterial associations, while rhinovirus (34%) and herpes virus type 6 (28%) are among the viruses. The detection rate of Streptococcus pyogenes in patients with acute tonsillitis was 6.3%. Typical respiratory viruses and herpes viruses can be found on the mucous membrane of the oropharynx and outside the phenomena of inflammation. This once again proves the importance of comparing the clinical manifestations observed in a patient and data on the structure of the microbiota of a particular locus, including to address the need for systemic or local antimicrobial therapy.

Acute purulent otitis media is an inflammation of the mucous membrane of the middle ear, a disease often encountered both in pediatric practice and in adult patients. The prerequisite for the development of this pathology is a violation of the function of the auditory tube, often occurring in inflammatory diseases of the upper respiratory tract, as well as in conditions of hypertrophy of the pharyngeal tonsil. Bacterial microflora, represented in most clinical cases by S. pneumoniae and H. influenzae, traditionally acts as an etiological factor of acute purulent otitis media. The authors of the article discuss the features of the clinical course of the disease, the causes of frequent recurrent course and the risk of developing purulent complications. The article highlights current problems of diagnosis and treatment of acute otitis media at different stages, including rational and justified use of antibacterial drugs. The authors consider the possibility of using topical anti-inflammatory and analgesic drugs as an alternative to the systemic use of non-steroidal anti-inflammatory drugs (NSAIDs) for rapid relief of the main symptoms of the disease. The authors conclude that ear drops containing lidocaine and phenazone, due to their combined action, are effective as a symptomatic treatment for acute otitis media, including its recurrent course, help reduce the frequency of prescribing antibacterial drugs, effectively relieve pain, reduce the duration of the disease and significantly improve the patient’s quality of life. Due to the high safety profile and the possibility of using ear drops with phenazone and lidocaine from birth, this dosage form finds its successful application in pediatric practice.

Impaired mucociliary clearance is the main mechanism of pathogenesis of acute and chronic diseases of the nose and paranasal sinuses. Viral infections have a negative impact on the condition of the mucous membranes of the upper respiratory tract, increasing the secretion of mucus by goblet cells, increasing its viscosity and reducing the intensity of the beating of cilia, making it difficult to remove mucus from the lumen of the respiratory tract and sinuses. The article discusses approaches to the treatment of acute and chronic sinusitis from the perspective of improving the functioning of mucociliary transport. Up-to-date requirements for drug therapy of both acute and chronic diseases of the nose and paranasal sinuses first necessitate a reasonable, evidence-based approach to the prescription of antibacterial agents, as the bacterial diseases account for no more than 2% of clinical cases in the sinusitis pattern, and even in this group, antibiotic therapy can only be prescribed in case of chronic, severe or complicated course of the disease. However, as most episodes of inflammatory diseases of the nose and paranasal sinuses are directly or indirectly associated with viral infection and post-viral changes, the next challenge facing the clinician is the choice of optimal therapy targeting the main link in the pathogenesis of the disease – correction of impaired mucociliary clearance. And the third issue that needs to be solved in planning drug therapy is the effectiveness and safety of the prescribed drug with the aim to minimize the risk of side effects. The authors of the article point to the effectiveness of the use of the herbal medicine Respero Myrtol, which has a mucolytic, anti-inflammatory and antibacterial effect, in the treatment of acute and chronic sinusitis, as well as protracted forms of rhinitis

Introduction. The most dangerous local complication of acute and exacerbations of chronic inflammatory diseases of the pharynx is the formation of abscesses in the structure of the cellular spaces of the neck. Paratonsillar abscess (PTA) is the most common abscessing lesion. In turn, parapharyngeal abscess (PFA) is often found in patients with PTA as its complication.Aim. To study the clinical, microbiological and pathomorphological features of parapharyngeal complications in patients with PTA.Materials and methods. The analysis of medical records of 50 patients with diagnoses of parathonsillar and parapharyngeal abscesses who underwent inpatient treatment at the otorhinolaryngological department of the N.I. Pirogov State Clinical Hospital No. 1 in the period from September 2021 to April 2023 was carried out. The studied patients were divided into 2 groups. In group 2 of patients (n = 25; F 10, M 15; average age -37.2 years ± 10.8 years) an isolated PTA was diagnosed. In the 2 group of patients (n = 25; F 10, M 15, the average age was 44.6 years ± 14.8 years) PTA was complicated by the development of PFA.Results and discussion. Associations of facultative anaerobic and obligate anaerobic microorganisms were found in all pus aspirates obtained from PTA and PFA. Monocultures of microorganisms were not isolated in any case. The detection of Fusobacterium necrophorum was associated with pronounced necrotic changes in the tissues of the tonsils and surrounding structures; Peptostreptococcus anaerobius with purulent melting of fiber tissue; Veillonella dispar with pronounced infiltrative processes in tissues combined with oral pathology in patients.Conclusions. The most common microorganisms in patients with PTA and PFA were Streptococcus pyogenes and Fusobacterium necrophorum. The activity of Fusobacterium necrophorum is associated with a more severe course of the inflammatory process in the near-pharyngeal space.

BACKGROUND:Acute bacterial sinusitis is one of the most common causes of prescribing systemic antibacterial drugs in otorhinolaryngology. With bacterial etiology of the disease, beta-lactam antibiotics are prescribed, in particular cefixim. Cefixim in the form of dispersible tablets has high clinical and bacteriological efficiency, as well as good tolerability in patients with acute sinusitis. OBJECTIVE:To study the therapeutic equivalence of two drugs of cefixim (reproduced drug Cefixim Express and reference drug Suprax Solutab) in patients with acute bacterial sinusitis. MATERIAL AND METHODS:60 adult patients with a diagnosis of acute bacterial sinusitis took part in a randomized open comparative clinical study. Patients of group 1 (n=30) received the drug Cefixim Express in the form of dispersible tablets 400 mg once a day. Group 2 (n=30) received Suprax Solutab in the form of dispersible tablets 400 mg once a day. The duration of treatment course was 7 days. All patients conducted general clinical and otorhinolaryngological examinations, assessment of symptoms of acute sinusitis, assessment of the general clinical impression of the therapy, tolerance of treatment, analysis of the frequency of unwanted phenomena before treatment, 3 days after the beginning of therapy and after the course completion (7 days). RESULTS:Recovery occurred in 63.3% of patients in group 1 according to the inspection on the 7th day of treatment and in 66.67% of patients in group 2. The rate of clinical symptoms regression by the end of therapy was comparable in the comparison groups. Hyperemia of the nasal mucosa, purulent nasal discharge and difficulty in nasal breathing (p<0.01) regressed by the 7th day in patients of both treatment groups. The incidence of adverse reactions on the 7th day of treatment in group 1 was 10%, in group 2 - 6.7% (p>0.05). CONCLUSION:The drug Cefixim Express has high therapeutic effectiveness in the treatment of acute bacterial sinusitis, comparable to Suprax Solutab. Cefixime EXPRESS has demonstrated a good tolerability and a favorable safety profile.

Otitis externa is one of the most common diseases in otorhinolaryngological practice frequently requiring prescription of analgesic medications and antimicrobials. The total of 2714 patients were included in the retrospective study to evaluate bacterial etiology, effectiveness, and safety of topical empirical treatment of patients with diagnosed otitis externa during 2018-2023. The most common pathogens isolated were Pseudomonas aeruginosa (38.1%), Staphylococcus aureus (24.2%) and Staphylococcus epidermidis (12.3%). Mixed bacterial infection was observed in 17.0% of patients. Majority of patients (76.1%) complained of erythema and swelling of the ear canal area, 38.2% had otorrhea, hearing loss (35.7%), otalgia (34.7%), itching in the ear (33.3%) and peeling of the epidermis of the external auditory canal (19.2%). Out of 2545 patients included in the analysis 92.1% received a combination drug containing polymyxin B sulfate, neomycin sulfate and lidocaine hydrochloride (Anauran) as monotherapy, whereas 7.9% received it in combination with other antimicrobials. Resolution of clinical symptoms within 7 days of therapy was observed in 97.0% of patients. Eradication of pathogens was observed in 95.1% of cases. In total 99.6% of patients reported completely no side effects during the treatment course suggesting high level of effectiveness and safety of the drug.

OBJECTIVE:To compare the data of pathomorphological and microbiological examination of fungal balls removed at paranasal sinuses endoscopic surgery.MATERIAL AND METHODS:A total of 148 samples were obtained from patients histologically diagnosed with fungal balls. Microscopic evaluation of the specimens stained according to the Gram method, Gomori-Grocott method and PAS-reaction method, revealed phase changes in the fungal balls conditioned by their different life cycles: the areas of young, mature and degenerating mycelium were detected. Degeneration lead to detritus formation. Detritus areas contained accumulated bacterial colonies. The cultural study of the fungal balls removed from paranasal sinuses, showed fungi growth in 17.6% of cases, while the pathomorphological study confirmed presence of fungi in every investigated sample. Aerobic and anaerobic microbiota of the sinuses contents was represented by multi-agent bacterial and fungal-bacterial associations. Statistical analysis of contingency between culture-positive rate of fungi and different bacteria detected in clinical samples from fungal balls revealed inhibitory influence of Pseudomonas aeruginosa on fungi growth, which might be a reasons of their low isolation rate. Supposedly in some cases the fungal balls consisted of dead fungi, or the sampling was done in the area of the fungal balls degeneration, which might also account for the low sensibility of the cultural method.

Purulent diseases in otorhinolaryngology are of great interest due to their widespread prevalence and the objective difficulties of treatment. One of the most frequently encountered nosological forms is purulent sinusitis. A key element in the complex treatment of bacterial sinusitis is systemic antibiotic therapy aimed at the eradication of pathobionts from the focus of infection. However, the increasing worldwide drug resistance of etiologically significant microorganisms complicates antibacterial chemotherapy of purulent sinusitis and raises questions about its future feasibility. The threat of a change from a resistance era to a post-antibiotic era is very significant, given the acute shortage of new antibiotics and the relatively rapid adaptation of bacterial microorganisms to them. The global community is therefore faced with the challenge of finding other drugs with antimicrobial activity. In recent decades, genetically modified virulent bacteriophages and phagolytes isolated on their basis are becoming increasingly attractive in the fight against purulent infections of various localizations caused by drug-resistant bacteria. This literature review focuses on the potential of phage therapy for acute bacterial sinusitis in an era of globally increasing bacterial strain resistance. The article details the causative agents of community-acquired and hospital-acquired acute sinusitis, the main mechanisms of bacterial antibiotic resistance, the effect of virulent phages on bacteria, and studies on the efficacy of phage therapy in the treatment of acute sinusitis. The facts outlined herein clearly indicate the efficacy of phage therapy, as well as therapeutic perspectives on using bacteriophages in the complex treatment of purulent sinusitis caused by antibiotic-resistant microbiota.

Introduction. The problem of infectious pathology of the pharynx and tonsils, manifested by sore throat, does not lose relevance. In the absence of indications for systemic antibacterial therapy, the main role of etiotropic treatment passes to topical use of drugs, including in the form of gargling. One of these is hydroxymethylquinoxalindioxide (Dioxidin®), which has recently received a new dosage form.Aim. To present an overview of the efficacy and safety of two dosage forms of Dioxidin® in the treatment of infectious and inflammatory pathology of the pharynx and tonsils.Materials and methods. The results of evaluating the efficacy and safety of 0.1% and 0.025% Dioxidine solutions for oropharyngeal rinsing in the treatment of adult patients with acute tonsillopharyngitis (ATP) or exacerbation of chronic tonsillitis (eCT) obtained during controlled comparative multicenter clinical trials conducted in 2017–2020 were analyzed.Results. By day 9 ± 1 of follow-up, relief of all local signs of inflammation according to pharyngoscopy was observed in 87% of patients with ATP or eCT who used 0.1% solution for rinsing and in 84% of patients with ATP who used 0.025% Dioxidine solution for rinsing. The severity of sore throat, assessed using a visual analog scale, by the specified time decreased by 63 points in the group using 0.1% solution and by 50 points according to the study of the effectiveness of 0.025% Dioxidine. 0.1% Dioxidine solution was more effective than 0.02% nitrofuran solution, and at a concentration of 0.025%, the effectiveness of Dioxidine was comparable to 0.01% benzyldimethyl[3-(myristoylamino)solutionpropyl]ammonium chloride. Both studies demonstrated a high level of safety of the two dosage forms of Dioxidine, which has no statistically significant differences from the safety assessments of comparison drugs.Conclusion. The presented data confirm the high efficacy and safety of 0.1% and 0.025% Dioxidin® solutions and suggest the possibility of implementing a differentiated approach to the treatment of inflammatory tonsillar pathology using two dosage forms of the drug.

The article evaluates the possibility of using silver proteinate to treat acute inflammatory diseases of the nasal cavity and paranasal sinus mucosa, as well as their complications. Acute rhinitis and rhinosinusitis are among the most common upper respiratory diseases. Viral pathogens are the main agents that trigger the pathological process. At the same time, the bacterial superinfection in some cases may develop due to viral infection, which promotes further development of lingering clinical symptoms up to a complicated course of the disease. The course of rhinosinusitis with underlying COVID-19 infection can be complicated by fungal superinfection and postnasal drip. For these reasons, topical drugs that could be used in the early stages of these conditions should have a number of properties, such as activity against most respiratory viruses and aetiologically significant bacterial pathogens; lack of opportunity to evolute and implement rapid resistance mechanisms in microorganisms; additive effects with other antibacterial drugs; acceleration of regeneration of the nasal cavity and paranasal sinus mucosa with underlying infectious alteration; vasoconstrictive and anti-inflammatory action, without causing an addictive effect, which enables repeated use of the drug in chronic diseases, as well as the absence of local and systemic toxic effects. Sialor (silver proteinate) has all the specified characteristics that were proved in various studies, and consistently demonstrated high clinical efficacy for many years.

Currently, the problem of acute rhinosinusitis continues to be relevant due to the frequent occurrence of this pathology. A certain difficulty is caused by the differential diagnosis of viral, post-viral and bacterial forms of rhinosinusitis, which carries the risks of irrational therapy. The authors of the article discuss the role of a viral infection in the etiology and pathogenesis of acute rhinosinusitis, the stages in the development of an inflammatory reaction on the mucous membrane of the nose and paranasal sinuses, and the disruption of mucociliary clearance. The authors consider options for the pathogenetic therapy of postviral sinusitis, concluding that the use of local combined preparations containing the mucolytic acetylcysteine and the vasoconstrictor component of tuaminoheptane sulfate is effective.

The cerumen impaction is a pathological accumulation of earwax in the external auditory canal, which is accompanied by hearing loss, heaviness and discomfort in the ear, which leads to a significant decrease in the quality of life. The authors of the article consider the most common causes of excessive formation of cerumen, the mechanisms that prevent the normal separation of cerumen from the ear canal and the age-related features of the composition of earwax. The article discusses various ways to remove cerumen impaction, indications and contraindications to them. The authors conclude that the most effective and gentle way to evacuate sulfuric masses is the use of cerumenolytics, drugs that break down and thin the cerumen impaction, which facilitates its subsequent removal. Cerumenolytics based on plant components gently affect the skin of the outer ear, which allows them to be used for the purpose of hygiene of the ear canal and prevention of the formation of excess cerumen.

Systematic analysis of various indicators of the educational process becomes important to assess the effectiveness of the training of residents. One of the most common tools for monitoring the effectiveness of the educational process is a questionnaire of students.OBJECTIVE:To analyze the results of the assessment of the quality of training in the residency of the Sverzhevky Research Clinical Institute of Otorhinolaryngology according to the survey of residents.MATERIAL AND METHODS:The study includes the results of an anonymous questionnaire survey of a sample group of residents of the residency of the Sverzhevky Research Clinical Institute of Otorhinolaryngology of the second year of study.RESULTS:The data obtained allow us to judge the satisfaction with the quality of training of the absolute majority of the interviewed residents, their active use of specialized electronic search engines, a high assessment of the level of lectures, the desire to improve their surgical training. The importance for the professional development of residents of participation in weekly scientific and clinical conferences of the Sverzhevky Research Clinical Institute of Otorhinolaryngology, meetings of the Moscow Scientific Society of Otorhinolaryngologists, traditional annual scientific and practical conferences of otorhinolaryngologists of Moscow, as well as in the activities of the Youth Council of the Institute is noted.CONCLUSION:The results of the survey create prerequisites for improving the educational process, the formation of professional competencies and readiness for independent work among residents.

The purpose of the expert council was to determine the place of cefpodoxime in the ABT algorithms for upper and lower respiratory tract infections and to form a consensus position on its use in clinical practice. Based on the available data, the possibility of including cefpodoxime in national guidelines for the treatment of rhinosinusitis, acute tonsillopharyngitis, community-acquired pneumonia (CAP), as well as infectious exacerbations of chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD) is being considered.

In recent years, inflammatory diseases of the nose and paranasal sinuses have been on the rise. In addition to infectious diseases, in the modern world a large percentage of the population suffers from allergic diseases. The approach to therapy and the choice of a drug should take into account the pathogenesis of the inflammatory reaction in the nasal cavity and paranasal sinuses. By exerting its effect, the drug should reduce hyperemia and swelling of the nasal mucosa, reduce the level of mucus secretion, improve the drainage of the paranasal sinuses, i.e. possess vasoconstrictive and anti-allergic properties. As such a drug, you can use the combined intranasal spray Frinozol, which basically contains cetirizine and phenylephrine. The use of Frinozol in the complex treatment of inflammation of the mucous membrane of the nasal cavity and paranasal sinuses contributes to the rapid and pronounced weakening of the symptoms of the disease, and is also the key to successful therapy.

The general toxicity was studied with an assessment of local tolerability, immunotoxicity, and pharmacological safety of the new medicine Dioxidine®, a solution for topical and external use, 0.25 mg/ml (0.025%) for the treatment of acute tonsillopharyngitis (JSC «Valenta Pharm», Russia). The experiment included 48 rabbits (divided in equal proportion by sex) randomized into 3 groups (n=16 in each group), whose back wall of the pharynx was irrigated with the studied substances for 28 days. Group 1 — control (aqueous solution of NaCl 0.9% for infusions at a daily dose of 4.0 ml/animal); group 2 — dioxidine (1.8 ml/animal); group 3 — dioxidine (4.0 ml/animal). The animals were observed for the entire period of drug administration — up to the 28th day of the experiment, as well as during the delayed observation period — up to the 58th day. The following indicators were recorded: lethality, daily monitoring of general condition and behavior, weight, feed and water consumption, respiratory rate, heart rate, blood pressure, electrocardiogram, mass coefficients of internal organs. Immunotoxicity, poisoning symptoms, adrenal insufficiency, as well as animal autopsy results were assessed. Clinical and biochemical blood tests, blood coagulation system analysis, urine analysis, macroscopic and histological examination of internal organs were performed. The absence of statistically significant differences in all evaluated indicators between the group of animals receiving dioxidine solution for topical and external use, 0.25 mg/ml (0.025%) at a dose of 1.8 ml/animal (equivalent to 15 therapeutic doses for humans), the group receiving dioxidine at a dose of 4.0 ml/animal (equivalent to 35 therapeutic doses for humans) and the control group allowed us to draw conclusions concerning the absence of signs of general toxicity, including toxic effects on the adrenal glands, cardiotoxicity, immunotoxicity, and toxic effects on other organs and organ systems, as well as local irritant and toxic effects after repeated irrigation of dioxidine on the back wall of the pharynx in rabbits for 28 days and during the period of delayed observation.

Background. Sore throat of infectious and inflammatory origin is one of the most common reasons for the prescription of antimicrobial drugs. The use of antimicrobial peptides (AMPs) for topical therapy may be a promising solution, due to the peculiarities of AMPs’ mechanism of action, taking into account the high importance of microbial resistance spread problem in relation to systemic etiotropic drugs.The aim of the study was to assess the formation of resistance to AMP Gramicidin S (GS) of clinical isolates of Streptococcus pneumoniae and Staphylococcus aureus, including strains resistant to antimicrobial drugs during repeated exposure, in the setting close to their actual use in clinical practice.Materials and methods. The object under study is AMP GS. The test microorganisms are reference strains of S.pneumoniae (ATCC 6303), S.aureus (ATCC 6538–P), and 10 strains of clinical isolates of each type of microorganisms, types with antimicrobial resistance (including MRSA). At the first stage, the antimicrobial activity of GS was evaluated by the method of microdilutions in plates by estimating the value of the minimum inhibitory and the minimum bactericidal concentrations (MIC and MBC, respectively). At the second stage, using reference strains and 4 clinical isolates of each microorganism, including types with antimicrobial resistance, resistance was formed in two ways simultaneously (with liquid and solid media) for 7 consecutive passages over 7 days with GS at concentrations equal to 0.5 and 1.0 MIC. The number of surviving microorganisms was estimated and the MIC and MBC were determined at each passage.Results. At the first stage, the MIC of GS in relation to S.pneumoniae was 8 µg/ml for 5 strains, 16 µg/ml for 5 strains, and 4 µg/ml for one. For 10 out of 11 strains of S.aureus, including MRSA, the MIC of GS was 4 µg/ml (for 1 strain — 8 µg/ml). For 4 strains of S.pneumoniae, MBC of GS was equal to MIC (16 µg/ml), for 7 strains MBC was 4–8 times higher than MIC, and mostly amounted to 32 µg/ml (for 1 strain — 64 µg/ml). MBC for 6 strains of S.aureus was equal to MIC (4 µg/ml), for the 5 remaining strains MBC was 2–8 times higher than MIC, but did not exceed 64 µg/ml. At the second stage, it was found that the estimated values of GS MIC and MBC with repeated exposure to GS remained at the same level for 7 passages in all strains, including those resistant to antibiotics in liquid and solid media.Conclusions. Gramicidin S demonstrated high bactericidal activity against reference strains and clinical isolates of leading pathogenic microorganisms S.pneumoniae and S.aureus, including strains resistant to systemic antimicrobial drugs, while MIC and MBC did not exceed concentrations contained in single doses of drugs used in clinical practice. During repeated exposure (7 passages in 7 days), there were no signs of the formation of resistance of test strains of pathogens, including those resistant to systemic antimicrobial medicines from the groups of beta-lactams, macrolides, fluoroquinolones, tetracyclines, aminoglycosides, etc.