Klebsiella pneumoniae (Kp) species complex is a genetically and ecologically diverse group of bacteria that causes a wide range of infections in humans and animals.The aim. To carry out biological characterization and genotyping based on the study of different loci of Klebsiella pneumoniae clinical isolates.Materials and methods. The object of the study was three Klebsiella pneumoniae clinical isolates from different biotopes of patients from a regional children’s multidisciplinary hospital. We used a complex of bacteriological, molecular genetic and bioinformatic methods. Genotyping of the isolates was carried out using the Pasteur Institute service for strains of the K. pneumoniae species complex.Results. All strains were sensitive to antimicrobial drugs from carbapenem (imipenem, meropenem) and tetracycline groups (tigecycline), and demonstrated high sensitivity to the Klebsiella polyvalent bacteriophage. The antibiotic resistance of the Kp ODKB-16 and ODKB-81 isolates to seven and eight antimicrobial drugs, respectively, was registeredBased on the results of multi-locus sequence typing, all strains were assigned to Kp1 phylogroup, K2 type and differed in sequence type, scgMLST629 profile and KL type. Kp ODKB-16 strain was identified as ST-65, scgST-11107, KL2; ODKB-07 strain – as ST-219, scgST-6401, KL125KL114; ODKB-81 strain – as ST-86, scgST-2800, KL2KL30. The virulence gene clusters AbST, CbST, YbST, SmST, and RmST have been characterized only in the genome of the Kp ODKB-16 isolate, allowing it to be characterized as highly virulent with multidrug resistance (MDR). Additionally, genes responsible for the synthesis of types 1 and 3 fimbrial adhesins were registered in all strains, and ter operon loci were identified only in Kp ODKB-16. Resistome analysis showed that all strains had 2b genotype. Plasmids were found in the genomes of Kp ODKB-81 (IncI2) and ODKB-16 (IncFIA + IncFIB + IncHI1B).Conclusion. We used a comprehensive framework for genomic taxonomy of clinical isolates, which can contribute to the unification of global and regional peculiarities of the developing and microevolution of bacterial pathogens.

The Republic of Sakha (Yakutia) is the largest administrative-territorial unit in the world, more than 40% of its territory is located beyond the Arctic Circle. At the same time, the population of the republic is the lowest among all subjects of the Russian Federation (0.32 people/km2). All this together significantly distinguishes this region from other territories of Russia. The purpose of this study: to assess the main manifestations of the epidemic process of chronic hepatitis C on the territory of the Republic of Sakha (Yakutia) at the stage of implementation of the national program for the elimination of viral hepatitis. Materials and methods. An epidemiological analysis of chronic hepatitis C and liver cancer was carried out for the period from 2000 to 2019. The incidence of liver cancer was assessed according to ICD-10, in which malignant neoplasms of the liver and intrahepatic bile ducts are summarized under code C22. Statistical analysis was carried out in the application package R. The study of differences in the distribution of incidence rates of chronic hepatitis C and malignant liver diseases between the Russian Federation and the Republic of Sakha (Yakutia) was carried out using the method of nonparametric assessment of the weighted average median of the Mann-Whitney test. Results and discussion. The decrease in the intensity of the incidence of acute and chronic hepatitis C in Russia was unidirectional in nature with a fairly close manifestation of their long-term movement. In contrast, in the Republic of Sakha (Yakutia) there was a significantly less pronounced decrease in the incidence of acute hepatitis C (4.9 times, rate of increase -6.2%), and the incidence of chronic hepatitis C in general for the entire analyzed period was cyclical and had a pronounced upward trend (2.4 times growth, rate of increase +2.6%). It was shown that there are statistically significant differences (p<0.01) between the median incidence rates of chronic hepatitis C and malignant liver diseases between the Russian Federation and the Republic of Sakha (Yakutia). Conclusion. To achieve the appropriate targets for hepatitis C elimination in the country, it is necessary to take into account the specific natural, climatic, social and ethnic characteristics of the Republic of Sakha (Yakutia). Keywords: epidemiology, morbidity; hepatitis C; liver cancer; The Republic of Sakha (Yakutia).

Background. For historical reasons, the incidence of tuberculosis (TB) varies significantly across geographic areas of the Russian Federation. This situation may be associated with the spread of the dominant Beijing genotype of M. tuberculosis (MBT) and of its aggressive B0/W148 subtype in the human population. Establishing a relationship between these genetic variants of MBT and the incidence of tuberculosis will serve as evidence of their epidemiological significance and a reason for decisionmaking in the TB epidemiological surveillance system.The aim of the study. To assess the relationship between the spread of the Beijing M. tuberculosis genotype and its B0/W148 subtype with the incidence of tuberculosis in the cumulative population of the European and Asian parts of the Russian Federation.Materials and methods. An epidemiological study was conducted, including an analysis of the distribution data of the Beijing genotype of MBT and its B0/W148 subtype (meta-analysis) in Russia and a study of TB incidence rates in the same regions. To assess the relationship, we used the Pearson’s chi-square test (χ2); the significance level when testing statistical hypotheses (p) was taken as 0.05.Results. In the European regions of the Russian Federation, a statistically significant relationship was found between the TB incidence and the prevalence of MBT Beijing genotype (χ2 = 17.2; p = 0.009) and the absence of such a relationship with the B0/W148 subline (χ2 = 9.9; p = 0.127). In the Asian part of the Russian Federation, a highly statistically significant association was found between the incidence of TB and both the incidence of MBT Beijing genotype (χ2 = 25.4; p = 0.0001) and the incidence of its B0/W148 subtype (χ2 = 29.6; p < 0.0001).Conclusion. A statistically significant relationship was established between the incidence of TB in the general population and the incidence of MBT Beijing genotype, regardless of the value of the average long-term TB incidence rate. In areas with high TB prevalence, a stable association was determined between the incidence rate not only with MBT of the entire Beijing family, but also with its aggressive subtype B0/W148.

Relevance. The globalization of the epidemic process requires improved surveillance of infectious diseases, in particular tuberculosis.Methods of molecular and genomic analysis are the most informative approaches that can radically change the management of this disease.Aims. To substantiate the necessary and sufficient volume of molecular studies for the exhaustive detection of most epidemic genotypes of Mycobacterium tuberculosis in Russia and the countries of the former USSR.Conclusions. Genetic lines L2 (Beijing) and L4 (Euro-American) cover more than 95% of all epidemic genotypes of M. tuberculosis in Russia and the countries of the former USSR. The development of rapid tests compatible with global data on genomic polymorphism will make it possible to conduct an epidemiological analysis of tuberculosis outbreaks within the country and to differ from cases of transbordern transmission of new genotypes outside.

Relevance. The problem of healthcare-associated infections (HCAI) is becoming increasingly important in epidemiological, social and economic terms. The most serious threat to hospital patients is multidrug-resistant Gram-negative organisms such as Pseudomonas aeruginosa and Klebsiella pneumoniae. The purpose of the study was to determine the etiological structure and sensitivity to antimicrobial agents of infectious agents associated with the provision of medical care in a children's multidisciplinary hospital. Materials and methods. The strains used in the work were obtained from patients aged from one to 15 years with severe infectious diseases. Additionally, swabs were taken from environmental objects. Bacteriological identification of selected strains was performed using standardized bacteriological algorithms and MALDI-TOF direct protein profiling of non-spore-forming microorganisms. Results. P. aeruginosa and K. pneumoniae were identified as the main causative agents of HAI with multiple resistance to AMPs in the children's multidisciplinary hospital, the source of which was mainly the respiratory tract. Multiple resistance to AMP was higher in K. pneumoniae, 38.9% of the studied isolates showed resistance to four drugs simultaneously. P. aeruginosa in 23.1% of cases was resistant to one AMP, in 15.4% - to two, four and seven AMPs. Conclusion. For a reasonable choice and optimization of antibacterial treatment of hospital patients, it is necessary to take into account the fact of wide circulation of hospital strains. Systematic monitoring of the constantly changing microbiological landscape of hospitals based on microbiological monitoring data and determining the levels of resistance to antimicrobial chemotherapy drugs will help reduce the risk and prevent the development of infections associated with healthcare.

A method for determining the viability of opportunistic pathogenic bacteria at the stage of biofilm formation after exposure to disinfectants with different active components was tested. The method is based on oxidation of tetrazolium salts by metabolically active cells with the formation of colored formazan derivatives and their quantitative spectrophotometry. The cell viability in the biofilm decreased after exposure to quaternary ammonium compounds and chlorine-containing disinfectants, but their effect was reversible. Dissemination of cells that had retained viability from the biofilm occurred after 24 h. The algorithm of testing, necessary controls, counting, and data interpretation are specified. The method can be recommended for use in laboratory diagnostics and clinical practice.

Relevance. The Irkutsk region belongs to the territories of Russia unfavorable for tuberculosis. The situation in the region is exacerbated by the existence of active tourism and trade and transport contacts with Mongolia, which is a country with a higher burden of TB.Aims. To assess the applicability of using subtype-specific PCR tests on clinical samples of TB patients to crossborder transmission analysis of the M. tuberculosis. Materials and methods. we investigated the cohort of 161 sputum and surgical specimens from newly diagnosed TB patients with a positive molecular genetic test (GeneXpert). The epidemic subtypes of the Beijing genotype (subtypes B0/W148, Central Asian, Asian-African 2) were identified by the method PCR with real-time detection (RT-PCR) with primers and probes of our own design. Results. The use of respiratory and surgical specimens with positive results of a molecular genetic test and microscopy makes it possible to differentiate epidemic subtypes of the Beijing genotype in 92.9% of cases. The frequency of detection of the Russian epidemic subtypes Central Asian (45.1%) and B0/W148 (20.3%) in clinical samples does not differ from data strains from the Irkutsk region. The «Mongolian» subtype Asian-African 2 of the Beijing genotype was not identified in the clinical samples in any case. Conclusions. The results indicate the applicability of the used tests for rapid monitoring as a stage in the complex of transboundary surveillance of tuberculosis.

Revalence. There is increasingly prominent growth of joint pathology, which in some cases assumes epidemic spread in recent period of science advancement. This tendency brought along interscience relations also establishing of post-non-classical period of science development. These changes bring on developing of new concepts in scientific views on estimate of studying essentials which in previous periods of science formation primarily drawing from inter discipline check could never met in cognitive work. Aim. Assess the prospects for studying comorbidity in the post-nonclassical period of science development on the example of interdisciplinary interactions of epidemic processes of tuberculosis (TB) and HIV infection. Results. A problem-oriented study identified three main «pain points» in the integrative impact of HIV infection on the spread of TB: the simultaneous development of epidemic processes with involvement in the general population; high activity of one-stage development of both infections; and positive statistically significant correlations in the compared pairs of infectious pathology indicators. Conclusion. New data on the formation of negative trends in the TB epidemic as influenced by HIV infection are based on the basic assumptions of the post[1]nonclassical period of scientific development and are realized through an interdisciplinary approach to the study of comorbidity.

Pseudomonas aeruginosa is one of the most problematic pathogens in medical institutions, which may be due to the ability of this microorganism to exist in a biofilm, which increases its resistance to antimicrobials, as well as its prevalence and survival ability in the external environment. This work aimed to evaluate the antimicrobial susceptibility of P. aeruginosa strains in planktonic and biofilm forms. We studied 20 strains of P. aeruginosa collected during 2018–2021 by specialists from the Laboratory of Microbiome and Microecology of the Scientific Centre for Family Health and Human Reproduction Problems. The identification of strains was carried out using test systems for differentiating gram-negative non-fermenting bacteria (NEFERMtest 24 Erba Lachema s.r.o., Czech Republic), and confirmed by mass spectrometric analysis and 16S rRNA gene sequencing. Antimicrobial activity was assessed by the degree of inhibition of cell growth in planktonic and biofilm forms (on a flat-bottomed 96-well plastic immunological plate). All clinical isolates of P. aeruginosa were biofilm formers, 47.6 % of the isolates were weak biofilm formers, and 52.4 % of the isolates were moderate biofilm formers. Planktonic cells and the forming biofilm of the tested P. aeruginosa strains were carbapenems-resistant. Biofilm formation was suppressed in more than 90 % of cases by the agents of the cephalosporin and aminoglycoside groups. Antimicrobial susceptibility of P. aeruginosa strains in the formed biofilm was significantly lower (p < 0.05). Carbapenems and cephalosporins did not affect the mature biofilms of the tested P. aeruginosa strains in more than 60 % of cases. Only non-beta-lactam antibiotics (ciprofloxacin and amikacin) suppressed the growth of planktonic cells and destroyed the mature biofilm. The revealed differences in the effect of the tested antimicrobials on the P. aeruginosa strains biofilms correlate with resistance to a number of antibiotics. To prevent biofilm formation in the hospital strains of P. aeruginosa, the use of ceftazidime may be recommended, and antimicrobials such as ciprofloxacin and amikacin may be used to affect mature biofilms of P. aeruginosa.

Background. The formation of biofilm structures by microorganisms living in the hospital environment is a serious medical problem. To conduct correct experimental studies, it is necessary to know the speed and efficiency of biofilm formation by clinically significant species of opportunistic bacteria. Aim: to study the kinetics of plankton culture growth and the rate of biofilm formation by clinically significant pathogens of infections associated with medical care to substantiate the methodology of further research. Materials and methods. The strains from the working collection of the Laboratory for Microbiome and Microecology of the Scientific Сentre for Family Health and Human Reproduction Problems were used. Experiments were carried out with conditionally pathogenic microorganisms of the Enterobacteriaceae family and non-fermenting gram-negative bacteria. The optical density was measured, the total microbial number of the cell suspension was determined, and the morphological structure of the biofilm was evaluated using a light microscope on sterile cover glasses for thespecies Pseudomonas aeruginosa, Klebsiella pneumoniae and Serratia marcescens. Results. The duration of the lag phase of the kinetic curve of cell growth varied in isolates of S. marcescens, P. aeruginosa and K. pneumoniae from 1 to 4 and 6 hours of cultivation, respectively. Despite this, the exponential growth phase was the same for all tested isolates and amounted to 4 hours. Thus, isolates of clinically significant species entered the stationary growth phase after 5–10 hours of cultivation and were characterized as fast-growing. On abiotic surfaces, after 8 hours of incubation of the tested cultures, the initial stages of the formation of biofilm structures were observed, after 20 hours the formed multilayer biofilm was visualized, after 24 hours succession occurred, new single cells were attached to the place of the detached structures. Conclusion. The data obtained on the duration of the main stages of growth kinetics compared with the visualization of the formation of biofilm structures on abiotic surfaces should be taken into account when studying the effects of disinfectants, antiseptics and antibacterial drugs on planktonic cells and biofilm associations of clinically significant opportunistic microorganisms.

Background. The problem of antibiotic resistance has remained significant for the medical community for more than half a century, since the first cases of resistance to penicillin were registered. The aim. Analysis of the long-term dynamics of changes in the antibacterial resistance of microorganisms and the creation of a collection of multi-resistant strains of opportunistic microorganisms. Materials and methods. The study included data from 3173 bacteriological samples of various loci of the human body for 2010 and 2020–2021. The sensitivity of isolated cultures was determined by the disk diffusion method to antimicrobial drugs of the following groups: penicillins, cephalosporins, fluoroquinolones, aminoglycosides, carbapenems, tetracyclines, macrolides, lincosamides, oxazolidinones, glycopeptides and others. Results. In the general structure of conditionally pathogenic microorganisms, a significant increase in the frequency of isolation of multidrug-resistant representatives of the genus Staphylococcus by two or more times was observed in 2021 compared to 2010 and 2020. We also observed a significant increase in the proportion of multidrug-resistant Streptococcus spp. and non-fermenting gram-negative bacteria. These changes marked the beginning of the creation of a collection of conditionally pathogenic microorganisms with multiple antibacterial resistance. In the structure of multiresistant microorganisms included in the “Collection of human microbiota of the Irkutsk region”, the leading positions belong to Klebsiella pneumoniae (23.81 %), Escherichia coli (19.05 %) and Staphylococcus aureus (22.22 %). Conclusion. Antibiotic resistance monitoring is an important measure to control the resistance of community-acquired and nosocomial (nosocomial) microorganisms both within a particular country and globally.

Relevance. Persons held in detention have a high risk of tuberculosis (TB), Aim. Comparative characteristics of the incidence of tuberculosis among prisoners in the penitentiary system and the population. Materials and methods. Тhe retrospective epidemiological analysis of long-term dynamics and the relationship between tuberculosis (TB) incidence rates among the population and contingents of the penitentiary institutions in the Eastern Siberian region of Russia (Irkutsk region) was carried out in 2004– 2019. Results. It has been identified that tuberculosis incidence rate (TB) of penitentiary institutions many times exceeds that in population (on average: in pretrial detention facilities by 10 times, in correctional facilities by 12 times). Increasing of tuberculosis incidence rate in the penitentiary system has signs of autonomy both in its various institutions and in comparison, with indicators of the population. Decreasing of incidence rate in the penitentiary system occurs mainly due to correctional facilities where over the analyzed period the incidence rate decreased by 5 times, and probability of tuberculosis developing decreased by 3.5 times. In the correctional facilities significant impact of incidence rate on TB situation in population (coinciding or delayed in time) has not been identified. The regression of tuberculosis incidence rate in pretrial detention facilities has been occurred at a much slower rate, with maintaining a high level of the probability of tuberculosis developing. A population impact of the TB situation in the population on pretrial detention facilities situation with a delayed time shift of 1–4 years was revealed. Conclusion. Since 2004, there has been a marked improvement in the TB situation in the penitentiary system. The incidence of TB in the penitentiary system does not have a significant impact on the spread of this infection in society. However, there remains a high risk of TB among those in prison.

In the article, the object of knowledge as one of the key concepts of any science is considered. Examples of understanding of this term at the present stage of the development of epidemiology are given. It is offered to take into account modern views on the epidemiology of infectious and non-communicable diseases to recognize behind them the uniform object of study and to treat it as a sore human body with a further exit to the main subject of knowledge which population morbidity is. Such understanding of an object of knowledge of epidemiology brings together it with such fundamental direction of medicine as pathological physiology. Both of these disciplines are engaged in any diseases (morbid conditions) irrespective of their origin and have identical approaches to their study at the level of generalizations. Fundamental differences take place only for the main subject of studying these sciences which are pathological processes for a pathophysiology and population morbidity for epidemiology. All this according to the principle of unity and conflict of opposites allows to prove the following conclusion. Now historical development of epidemiology in integration with a pathophysiology, promotes forming of higher levels and generalization of this preventive discipline.

The objective of the study: to evaluate the impact of HIV infection on the nature and results of surgical interventions in respiratory tuberculosis (RTB) patients with the relevance of their immune status.Subjects and Methods. An ambispective observational study with continuous sampling included 565 patients above 18 years old who underwent surgical interventions. The study participants were divided into RTB+HIV Group (90 patients) with HIV-associated respiratory tuberculosis and RTB Group which included 475 HIV negative patients with respiratory tuberculosis. In RTB+HIV Group, patients were divided into three subgroups: with CD4-lymphocyte count below 200 cl/μL (n = 41), 200-499 cl/μL (n = 26), and 500 or more cl/μL (n = 23).Results. Compared to RTB Group, RTB+HIV Group was found to have less frequent resection surgery (24%; p < 0.0001; OR = 3.0) with acomparable frequency of collapsed surgery (4%; p > 0.05) and much more frequent thoracic diagnostic surgery (11%; p < 0.0001; OR = 10.6) and extrathoracic surgery (50%; p < 0.0001; OR = 6.8). In RTB+HIV Group, patients with CD4-lymphocyte count below 200 cells/μL (46%; p < 0.05) who had no resection surgery predominated, and the rate of collapsed surgery was 2.4% (p < 0.0001). There were no statistically significant differences in the incidence of postoperative complications for each individual type of surgery when stratifying participants by CD4-lymphocyte count in the intergroup comparison, as well as in RTB+HIV Group.

Relevance. Microbiological monitoring in medical organizations is an essential part of ensuring epidemiological safety in the provision of medical care. The study of the sensitivity of pathogens to antibacterial drugs allows us to reasonably approach the prescription of empirical therapy and form a form of antibacterial agents for medical organization. The purpose of the work was to study the species composition of pathogens of generalized purulent septic infections (GPSI) in a children's multidisciplinary hospital and determine their resistance to antibacterial drugs. Materials and methods. Analysis of microbiological analysis data of material taken from patients with GPSI treated in children's multidisciplinary hospital in the period 2013-2018 was carried out. A total of 572 cultures were studied. Results. It was found that the largest specific gravity in the structure of GPSI was occupied by gram-negative microorganisms, the proportion of which significantly decreased from 73.0% in 2013 to 48.1% in 2018. Gram-positive microorganisms were found in 27.0 ± 8.1% cases, while a significant increase in the proportion of fungi from 5.4 to 30.7% was observed. The antibiotic resistance of the main pathogens has been studied. Among non-fermenting gram-negative bacteria, the highest (p < 0.05) multi-resistivity indicator was found in Acinetobacter baumannii (50.0 ± 6.8%). Enterococcus, having high natural resistance to a number of antibiotic groups, leave the possibility of effective action of the preparation of the group of glycopeptides (vancomycin) against Enterococcus faecium. Conclusions. High pathogens to applied antibacterial preparations is shown. The obtained data make it possible to form an up-to-date form of antimicrobial drugs for use in children's hospitals, to develop measures that inhibit the development of resistance in pathogens of purulent-inflammatory diseases.

The objective: to study treatment efficacy in new pulmonary tuberculosis patients depending on the genotypes of M. tuberculosis in the Republic of Sakha (Yakutia).Subjects and methods. The authors studied the clinical course and outcomes of 312 bacteriologically confirmed new pulmonary tuberculosis cases among patients admitted to hospital in 2010-2014. Molecular genetic tests included deletion analysis of RD105 and RD207 regions of DNA of the pathogen followed by MIRU-VNTR genotyping at 24 loci.Results. In the Republic of Sakha (Yakutia), the Bejing and S genotypes are of epidemic importance, these genotypes prevail among drug resistance mycobacteria. Tuberculosis caused by the Bejing genotype had multiple (MDR) and extensive drug resistance (XDR) in 30.6% of cases, its subtype CC2/W148 - in 85.3%. The S genotype was accompanied by MDR/XDR in 69.7% of cases, subtype S256 - in 78.9%. The treatment of patients was highly efficient according to the criteria of sputum conversion (92%) and cavities healing (89.4%). The lowest rates were observed in case of tuberculosis caused by the Bejing and S genotypes due to their subtypes CC2/W148 and S256. Clinical cure of new pulmonary tuberculosis caused by the Bejing genotype was achieved in 73.4% of cases, by subtype CC2/W148 - in 41.2% with a significantly higher proportion of treatment failures and lethal outcomes of tuberculosis than in other subtypes of this genotype. With the S genotype, the clinical cure was achieved in 72.7% of patients, with no significant difference in the incidence of unfavorable outcomes in patients with subtype S256.

Журнал для непрерывного медицинского образования врачей Гепатоцеллюлярная карцинома, ассоциированная с гепатитами В и С, у монголоидов и европеоидов Северо-Восточной Азии ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ 1 Монгольский национальный университет медицинских наук, 14210, г.Улан-Батор, Монголия 2 Монгольская академия медицинских наук, Улан-Батор, Монголия 3 Федеральное государственное бюджетное образовательное учреждение высшего образования «Иркутский государственный медицинский универ-

We compared the effects of disinfectants on biofilms of 10 Pseudomonas aeruginosa strains isolated from different loci of patients with purulent-septic infections. Identification was carried out by standard bacteriological methods. To substantiate the prospects of using in hospitals and to assess the effect of disinfectants on P. aeruginosa biofilms, the following disinfectants were used in various concentrations: Sekusept Aktiv, A-DEZ, and Monitor Oxy. All clinical strains of P. aeruginosa showed the ability to form biofilms. Both oxygen-containing and quaternary ammonium compounds effectively inhibited the formation of biofilms. In more than 50% cases, disinfectants with different active ingredients did not destroy pre-formed of P. aeruginosa biofilms.

In multidisciplinary hospitals, there are conditions conducive to the emergence of healthcare-associated infections: high concentration of people with reduced immunity in a limited area, the presence of a significant number of sources of contagion (patients and carriers), a change in the biocenosis of the mucous membranes and skin of patients and medical personnel under the influence of widespread use of antibiotics and cytostatics. The aim of the research was in the intercomparison of the standardized bacteriological algorithms and the MALDI Biotyper system in the microbiological diagnosis of pathogens as illustrated by the healthcare-associated diseases.Materials and methods. Seventy-eight patients of a multidisciplinary hospital of a regional level (Irkutsk) in 2018–2019 were examined. The age of patients ranged from 1 to 15 years. The material for the study was blood, sputum, swabs from the tracheobronchial tree, throat, nose, wound, abdominal fluid, cerebrospinal fluid, and swabs from environmental objects. Identification of the isolated cultures (78 bacterial strains) was carried out using generally accepted bacteriological methods, as well as using the MALDI Biotyper system.Results and discussions. In the structure of healthcare-associated infections, Pseudomonas aeruginosa occupied a leading position. Not all isolates of microorganisms were identified by standardized bacteriological methods. The identification of strains with characteristic manifestations of physiological and biochemical characteristics was more reliable. Identification difficulties arose in the presence of atypical properties of microorganisms when the use of MALDI Biotyper would be crucial.Conclusion. It is necessary to apply an integrated approach to conduct reliable diagnostics of pathogens. It includes standardized bacteriological methods and methods for identifying microorganisms using mass spectrometry in the subsequent stages.