Objective. To compare analytical parameters and sensitivity between BACT/ALERT® 3D 60 and Yunon® Labstar 50. Materials and Methods. The study included 20 species of clinically significant microorganisms isolated from blood (20 strains for each facultative anaerobic species and 10 strains for each aerobic species). For each strain, individual volumes of the inoculation dose were selected with the control of CFU value. In the case of obtaining a stable CFU value in the range 2–10 per 100 µl of bacterial cell suspension, 100 µl of suspension was inoculated into vials with nutrient media for each analyzer, followed by an analysis of the cultivation time, the presence or absence of a growth signal, and average CFU values. Aliquots of the vials contents were also inoculated onto solid nutrient media to evaluate false positive and false negative results. Results. It was revealed that the main analytical parameters of both devices were comparable. In addition, for two blood culture systems, the maximum limit value of CFU per sample was set, at which the probability of the growth signal absence from both analyzers significantly increased – 2 CFU per vial. At this value and values below, the analyzers did not detect the growth of microorganisms significantly more often. Also, a comparable median inoculation dose of 5 CFU per vial was established for both devices. Conclusions. The devices included in the study have comparable analytical parameters and allow to obtain a positive growth signal after inoculating material containing < 10 CFU per vial. However, it is necessary to consider increased probability of a negative result in case of inoculation dose equal to CFU ≤ 2.

A microbial identification method using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF) is an innovative dimension in proteomic analysis. MALDI-ToF mass spectrometry allows not only determine the species and subspecies bacteria, but also determined by proteomic analysis and the corresponding software degree of kinship analyzed strains, which allows this method to be used in epidemiological studies and in comparing strains isolated from patients with chronic infection. The aim of this study was to evaluate the possibility of using protein spectra of microorganisms obtained by MALDI-ToF mass spectrometry as additional microbiological criteria in assessing the course of the infection process caused by Burkholderia cepacia complex among patients with cystic fibrosis. The analysis of protein profiles, which were obtained by using MALDI-ToF mass spectrometry (Bruker Daltonik GmbH, Germany), was performed by using flexAnalisis 3.0 software (Bruker Daltonik GmbH, Germany). Differences in protein profiles of Burkholderia spp. isolates were found depended on the stage of infection of a cystic fibrosis patient with prolonged colonisation of the lower respiratory tract. The protein profiles of Burkholderia spp. isolates that formed a heterogeneous population containing both NCV and SCV morphotypes were also studied. A regular dynamic monitoring and comparison of protein profiles of microbial strains can be useful in forecasting effort of the clinical course of the disease, as well as in assessing of risks of severe infectious complications development.

Background:Young farm animals are susceptible to opportunistic infections which may cause economic losses due to mortality and poor weight gain. The development of antimicrobial resistance and the desire to improve therapy efficacy and safety are the reasons to seek for new antibacterial drugs ensuring rapid recovery with minimum adverse events. Aim:To estimate the efficacy of DOKSI AVZ 500 in respiratory pathologies in young pigs. Methods:The study was conducted in 65-70-day-old Yorkshire piglets with signs of bacterial respiratory pathologies. The animals were treated with the test drug for 3 or 5 days. The reference group received TETRAMAX 500 which is similar to the test drug in terms of chemical structure, mechanism of action, and activity spectrum. The animal's status was assessed using clinical examination, clinical blood count, and bacteriological tests. Results:Both test and reference drugs were well tolerated and ensured the animal recovery within about 4 days. The recovery was accompanied by normalization of hematological parameters and flora composition. The bacterium associated with the disease development, Streptococcus suis, was virtually completely eliminated in all groups. No adverse events were noted. After the treatment, all the animals readily gained weight and live market quality. Conclusion:DOKSI AVZ 500 was a highly efficient therapy for respiratory pathologies caused by the resident opportunistic flora in piglets. It has also shown noninferiority vs. TETRAMAX 500 in terms of all the health-related parameters and thus can be recommended for introduction in veterinary practice in pig farms.

BACKGROUND:Mycobacterium abscessus complex (MABSc) causes chronic infection in patients with concomitant structural changes in the respiratory tract, which is especially important for patients with cystic fibrosis. To isolate an MABSc culture from clinical material, a variety of nutrient media are used. For species determination of microorganisms isolated on these media, additional identification methods are used, for example, polymerase chain reaction, sequencing, or mass spectrometry. The latter method is relatively easy to implement but requires improvement, due to the identification inaccuracy of nontuberculosis mycobacterias in general. Consequently, a set of nutrient media may be important for subsequent identification by mass spectrometry. METHODS:The study was conducted on 64 strains of MABSc representatives: 56 strains were obtained from patients with cystic fibrosis and 8 strains from patients with pulmonary pathology unrelated to cystic fibrosis. The obtained MABSc strains were transplanted to the universal chromogenic medium and the selective medium for the Burkholderia cepacia complex (BCC) isolation. Species identification was carried out by mass spectrometry based on matrix-activated laser time-of-flight desorption/ionization (MALDI-ToF MS). Microbial identification is based on a comparison of the obtained mass spectra with reference spectra from the database. Microorganisms were identified based on the coincidence degree (Score value). Sample preparation for microbial identification by mass spectrometry was carried out by an extended direct application method. Fragments of the rpoB and hsp65 genes with lengths of 752 bp and 441 bp, respectively, were used as molecular markers for subspecific identification of MABSc strains. RESULTS:A comparison of the peaks obtained after mass spectrometry of MABSc strains isolated on the studied nutrient media showed significant differences between these indicators selective medium for the BCC isolation with the supplement of iron polymaltose hydroxide (III) and universal chromogenic medium (P < 0.001) and selective medium for the BCC isolation with universal chromogenic medium (P < 0.001). Twenty-five strains of MABSc representatives were sequenced: results of subspecies determination in strains isolated on the universal chromogenic medium coincided with the results sequencing in 13 (86.6%) strains out of 15. CONCLUSION:MALDI-ToF mass spectrometry allows microbial identification in a short time and with minimal cost, but it does not yet allow the proper identification of the subspecies of certain microbial groups, such as MABSc. Cultivation methods need optimization and new approaches to the extraction process of the bacterial protein fraction.

Background. Mycobacterium abscessus complex is one of the most abundant groups of rapidly growing non-tuberculous mycobacteria that has been increasingly more common causing infections of various localization, especially in cystic fibrosis (CF) patients. Microbiological diagnosis of such infections in case of using matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry is often complicated due to mycobacterial cell features, which requires to perform a diagnostic optimization. The aim of the study was to evaluate the accuracy of Mycobacterium abscessus strains identification isolated on universal chromogenic medium and selective medium for Burkholderia cepacia complex (BCC) isolation. Materials and methods. Total number of 64 strains were selected for the study cultured in parallel on universal chromogenic medium and selective medium for BCC isolation. The identification of isolated microorganisms was carried out using the MALDI-ToF mass spectrometry on Microflex LT device. Statistical data processing was carried out using the StatTech program v.2.1.0. Results. The correlation analysis between identified data and used nutrient media was carried out showing that identification of mycobacteria isolated on chromogenic medium vs. medium for BCC isolation was more accurate. Conclusion. The study revealed that the composition of the nutrient medium affects the accuracy of MABSc member identification, which can be taken into account while developing protocols for optimizing and increasing the accuracy for this group of bacteria using MALDI-ToF mass spectrometry. Despite this, in the context of such a complex pathology with high comorbidity as CF, taking into account the universality of chromogenic medium we studied and often polymicrobial nature of infections in CF, it is rational to use selective media for primary inoculation of the studied material, including the medium for BCC isolation. However, after the initial inoculation, mycobacteria can be subcultured on chromogenic medium to assess cultural properties and improve the quality of species identification.

Sutterella wadsworthensis are Gram-negative, non-spore-forming, bile-resistant, microaerophilic bacteria. IgA-specific serine endopeptidase is among one of the crucial biochemical traits of S. wadsworthensis. In scientific publications, Sutterella spp. has been linked to ulcerative colitis, autism spectrum disorder, and obesity in children. Moreover, after analyzing various clinical complications in obese patients, it was found that Sutterella spp. influences an increase in insulin resistance, which subsequently leads to the development of type 2 diabetes. Here, the fecal microbiome from 156 patients in the pediatric department was analyzed, of which 23 children comprised control group, 23 children — with obesity lacking concomitant pathology, 110 children — with obesity and concomitant pathology. The study was aimed at determining a correlation between microorganism S. wadsworthensis and types of obesity in children as well as its role in developing this pathology. As a result, a direct relationship was revealed between the isolated bacillus and obesity without concomitant pathology in girls vs boys aged 14 to 17 years, and data were also obtained that S. wadsworthensis was isolated significantly more often. In addition, it was decided to analyze microorganisms associated with S. wadsworthensis in order to identify microbiome members characteristic of obese people. Statistical processing revealed a marked significant positive correlation with the isolation of Streptococcus spp., S. anginosus, C. perfringens, S. aureus and W. confusa. In addition, the ability of S. wadsworthensis to reduce the functionality of the intestinal antibacterial immune response due to the enzyme IgA-specific serine endopeptidase can lead to developing inflammation and penetration of various pathobionts into enterocytes. Thus, our and others study results indicate the controversial importance and a need to further investigate S. wadsworthensis both in obesity and other gastrointestinal diseases.

Background: In patients with cystic fibrosis (CF), representatives of the fast-growing Mycobacterium abscessus complex (MABSc) are often distinguished, but the culture of the material taken from such patients increases the growth time. We analyzed the terms of cultivation of MABSc representatives on dense nutrient media and also evaluated the productivity of a modified nutrient medium based on agar for the isolation of Burkholderia cepacia complex (BCC). Methods: Sixty-four strains of MABSc isolated from patients with CF and suspected tuberculosis were analyzed. The material from the patients was cultured on a universal chromogenic medium, 5% blood agar, yolk-salt agar, selective medium for isolation of BCC, and Löwenstein–Jensen medium. The cultures were incubated for 5 days (37°C, aerobic conditions), after for 23 days (28°C, aerobic conditions). The productivity of the developed nutrient medium was evaluated by the number of cells that gave visible growth after culturing 0.1 mL of a bacterial suspension of 103 CFU/mL. Results: 76.8% of the strains grew in a 2-week period, and 23.2% of the strains were obtained at a later date from 18 to 28 days (average: 21.23 days). The modified medium with a concentration of 240 mg of iron (III) polymaltose hydroxide proved to be the most optimal for the isolation of MABSc. Conclusion: When using a chromogenic medium for culture material from patients with CF, it is necessary to extend incubation up to 28 days to increase the probability of MABSc isolation. The modified BCC medium showed a good selectivity result but required further investigation.

BACKGROUND:Microbiological diagnosis of mycobacteriosis is often difficult, as it is necessary to differentiate between transient colonization and active infection. METHODS:We studied the cultural properties of Mycobacterium abscessus complex (MABSc) strains obtained from cystic fibrosis patients, and also analyzed composite correlation index (CCI) values in patients with repeated MABSc inoculation and their correlation with the presence of clinical and radiological manifestations of mycobacteriosis. RESULTS:As a result, MABSc more often grew in S-form colonies in patients without clinical manifestations of chronic infection, while R-form colonies were characteristic of patients with chronic infection and clinical symptoms. At the same time, in patients examined once, no growth of colonies in the R-form was recorded, and all strains produced growth in the form of either S-colonies or in the S- and R-forms simultaneously. Statistically significant results were obtained for the relationship of the CCI with the clinical and radiological picture. In addition, a heterogeneous MABSc population with low CCI score values correlated with the development of mycobacteriosis in patients. In patients with high CCI score values (homogeneity of isolated strains), on the contrary, there were no radiological or clinical signs of the disease. CONCLUSION:These data make it possible to build a strategy for monitoring patients depending on changes in CCI score values. The use of CCI matrix to evaluate microorganisms' identification results is a potentially new method that expands the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Background: The variety of morphological and cultural characteristics of acid-resistant bacteria (ARB) makes it possible to use microscopy and estimate the growth rate and pigment formation when cultivating on solid egg media for preliminary identification only as additional indicative methods. It is necessary to develop new approaches for the cultivation and primary identification of ARB isolated from the biological material. It will allow to obtain data on the prevalence, structure, epidemiological, and clinical features of infectious processes caused by opportunistic ARB. Methods: Three hundred and sixty strains of ARB were isolated from the various biological materials obtained from the patients during the examination for tuberculosis. All biological material samples were negative on Mycobacteria tuberculosis complex. Species identification of all bacteria was performed by matrix-assisted lazer desorption/ion-ization time-of-flight mass spectrometry. The cultural characteristics of ARB were evaluated on a universal chromogenic media. As a selective additive, a mixture of bacitracin and polymyxin sulfate which had no effect on ARB was tested to suppress concomitant Gram-positive and Gram-negative microflora. Results: Cultural characteristics were identified and described for all tested representatives of fast-growing nontuberculous mycobacteria (NTM), as well as for all types of nocardia, gordonia, and streptomycetes. Representatives of other genera of ARB on a universal chromogenic media gave meager growth or did not show it at all. When inoculated on a universal chromogenic media with a selective addition, 100% of the strains from the ARB group showed abundant or moderate growth. Incubation time for fast-growing species was up to 7 days; for slow-growing species, it was up to 28 days. Concomitant control strains of Gram-positive and Gram-negative bacteria on universal chromogenic media with selective growth additive did not show the growth. Conclusions: The use of a universal chromogenic media allows to preliminarily identify NTM and other ARB by cultural characteristics. The addition of bacitracin and polymyxin sulfate does not reduce the growth properties of ARB, which can be used when working with both biological materials and for the isolation of pure ARB cultures from mixtures with other bacteria.

Background: Problem with mass spectrometers is the difficulty in identifying some genera of acid-fast bacteria (AFB). Due to the peculiarities of the colony architectonics (the formation of dry colonies with a complex structure) and the structure of the cell wall, the probability of obtaining a sufficient amount of ribosomal proteins is significantly reduced. This problem is partially solved using an extended method of direct application and extraction with formic acid, which can significantly improve the quality of the identification. Methods: The study analyzed strains of microorganisms obtained during the examination of patients with suspected tuberculosis. In total, 287 strains of nontuberculous mycobacteria (NTM) were obtained. In addition, 63 strains of the most common bacteria from the AFB group were analyzed. Matrix-assisted laser desorption/ionization (MALDI) was used. Three main methods of sample preparation of microorganisms according to the manufacturer's recommendations for use with the MALDI-time-of-flight (ToF) mass spectrometry method were used in the work: Direct coating method, extended direct coating method, and formic acid extraction method. Results: When evaluating the influence of the cultivation medium on the result of NTM identification by MALDI-ToF mass spectrometry, statistically significant results of the influence of the medium on the result of NTM identification were revealed for all compared parameters. Conclusions: Optimization of sample preparation protocols and assessment of the impact on the identification of new methods of cultivating microorganisms can significantly improve the quality of the identification of both clinically significant microorganisms from the AFB group and saprophytic microflora, the clinical significance of which has not been proven at the moment.

Background:The nutrient medium effects on the quality of the matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectra. The standard library includes spectra of microorganisms of the family Mycobacteriaceae grown on the Lowenstein-Jensen and Middlebrook Media. There are new methods for culturing microorganisms from this group, including inoculation on chromogenic media. Methods:The study included 240 strains of NTM isolated from patients during tuberculosis examination. The inoculation of the biological material was carried out on solid culture media of Lowenstein-Jensen and universal chromogenic media. Identification of bacteria from both types of media was performed by MALDI-ToF mass spectrometry (Bruker Daltonik GmbH, Germany). Analysis of protein spectra was performed. Results:For all strains, the spectra revealed both coinciding peaks (regardless of the cultivation medium) and significant differences, including the complete absence of some peaks depending on the medium. The results of a greater divergence of peaks in mass and intensity were obtained for slow-growing species than for fast-growing species. For all analyzed cultures, the number of peaks in the mass spectra was significantly higher when cultivating on a universal chromogenic medium than on a Lowenstein-Jensen medium. Conclusions:The use for NTM cultivation of a universal chromogenic medium makes it possible to obtain acceptable identification results by MALDI-ToF mass spectrometry using a standard library.

Background:Over the past 10 years, the clinical importance of opportunistic bacteria of the order Actinomycetales has increased significantly. While many problems for the Mycobacterium tuberculosis complex have been solved, for nontuberculous mycobacteria, some questions remain open. These pathogens have a number of structural features that allow them to persist in the external environment for a long time. Methods:The main inclusion criteria were cultural characteristics in assessing the growth of microorganisms on solid egg media. If nontuberculous mycobacteria (NTM) growth was detected, identification signs were carried out using the DNA hybridization method. Subsequently, these cultures were identified using the matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectrometry method. In case of obtaining unacceptable results of identification from primary inoculations, re-identification to obtain pure cultures was carried out after transferring the material from primary media to agar media: 5% blood agar and universal chromogenic medium. When re-identifying isolated cultures using MALDI-ToF mass spectrometry, all isolated cultures were analyzed, regardless of whether they belonged to the NTM group or not. Results:DNA hybridization, which accounted for 59.5% of the total number of cultures included in the study, performed species identification of 188 strains. Using MALDI-ToF mass spectrometry, 345 strains were identified. Conclusion:The use of methods based on DNA hybridization makes it possible to identify quite accurately some of the most common NTM species. MALDI-ToF mass spectrometry is an important technique to allow species identification of most Actinomycetales. However, algorithms to standardize methods for their isolation from clinical material are needed.

Практически каждый пациент, который обращается за помощью в медицинские учреждения, сталкивается с заболеваниями зубочелюстной системы. Именно по этой причине этой проблеме уделяется серьёзное внимание со стороны врачей-стоматологов различной специализации

Background:For the present, matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectrometry is the fastest and the most correct method for species identification of microorganisms. Apart from species-level identification, it allows to use a variety of approaches for the analysis and comparison of protein spectra of microorganisms of the same species, which are isolated from a patient at various disease states, that can be used in routine microbiological practice in laboratories fitted with mass analyzers. Methods:Two strains of Mycobacterium fortuitum and two strains of Mycobacterium peregrinum were isolated from sputum samples, which were obtained from patients with different clinical aspects of mycobacteriosis, whereat were reinoculated on the universal chromogenic culture medium "UriSelect 4." Further, the MALDI-ToF mass spectrometry method was used, aiming to obtain protein profiles, which were analyzed using the FlexAnalysis 3.0 software package. Results of the statistical proteomic comparison of mass spectra were visualized using MALDI Biotyper 3.0 Offline Classification software. Results:Presented clinical examples demonstrate that strains of the same species, which are isolated from the same patient at different times of infection, change their cultural properties. Dynamic changes in cultural properties are reflected in changes in protein profiles by comparison spectra of isolates at different stages of colonization, which is reflected in the correlation with the clinical condition of the patient. Conclusion:Thus, the mentioned examples of proteomic analysis, using MALDI-ToF mass spectrometry, demonstrate the possibility of subtyping of strains, that are isolated on a universal chromogenic culture medium, in case of detection in the culture signs of population's heterogeneity, based on cultural properties.

Background: The increase in the number of patients at risk for opportunistic infections caused by rare bacteria, which include individual representatives of acid-resistant bacteria (ARB), is a serious problem in modern health care. Significant difficulties in the etiological diagnosis of mycobacteriosis, nocardiosis, and actinomycosis are associated not only with the problem of identifying the main pathogens but also with certain difficulties in isolating pathogens from biological material. Methods: The research provides data on 402 strains of ARB, which were isolated from various biological materials obtained from patients during examination for tuberculosis. All samples of biological material were negative on the Mycobacterium tuberculosis complex. The isolates were identified on the MALDI-ToF mass spectrometer. The cultural characteristics of ARB were evaluated on the solid Löwenstein–Jensen egg-based culture media, universal chromogenic media, and 5% blood agar with lamb blood. Results: The studies carried out indicate the possibility of culturing ARB representatives on agar media. At the same time, based on the comparison of the growth properties of ARB, it was found that the universal chromogenic media provides more acceptable conditions for the isolation of nontuberculous mycobacteria (NTM) compared to blood agar. The comparison of the growth rate of bacteria did not reveal significant differences for fastly growing NTM. For slowly growing species, the growth rate on blood agar was lower than on chromogenic media and on the Löwenstein–Jensen media. Conclusion: Thus, the use of a universal chromogenic media during incubation makes it possible to isolate and preidentify representatives of the ARB under the conditions of standard operating procedures of the microbiological laboratory.

Introduction. Violation of sputum evacuation in patients with cystic fibrosis leads to the persistence of microorganisms. Most often, the microorganisms are isolated from sputum in patients with cystic fibrosis: Staphylococcus aureus , Pseudomonas aeruginosa , Burkholderia cepacia complex , etc. For the treatment of infections caused by P. aeruginosa , the following groups of antibiotics are used: aminoglycosides, carbapenems, polymyxins, cephalosporins, fluoroquinolones, inhibitor-protected penicillins and fosfomycin. Aim. To the study is to determine antimicrobial resistance in P. aeruginosa isolated from patients with cystic fibrosis. Materials and methods. An analysis of 87 results of sputum, biomaterial from the posterior wall of the pharynx and nose was made. Results and discussion. Biomaterial was taken from the nasal in 4.6% cases, from the posterior pharyngeal wall in 35.6% and sputum in 59.8%. The lowest level of resistance was registered in strains isolated from the nasal cavity. Microorganisms isolated from the posterior pharyngeal wall showed a higher level of antibiotic resistance. The sensitivity data of sputum isolates were similar to the results from the posterior pharyngeal wall. The highest level of resistance was obtained to aminoglycosides (19.3%) and carbapenems (14.8%). In addition, 12.5% of P. aeruginosa isolates were resistant to sodium colistimethate, 10.2% to fluoroquinolones. The lowest level of insensitivity was found to cephalosporins (5.7%) and protected beta-lactams (4.5%). The revealed trend of decreasing sensitivity, in our opinion, is associated with a greater frequency of antibiotic use. Conclusion. Chronic P. aeruginosa infection in patients with CF contributes to a more severe course of the disease and increases the risk of complications.

Recently, both in Russia and around the world, the number of cases detecting acid-fast microbial members from the order Actinomycetales while developing human bacterial infections has been increased. The most important pathogens in this bacterial order are the members from the families Mycobacteriaceae, Nocardiaceae, Gordoniaceae, Tsukamurellaceae, Promicromonosporaceae, Brevibacteriaceae, Streptomycetaceae. This work is devoted to analyzing prevalence and species diversity of representatives of the family Streptomycetaceae from the genus Streptomyces isolated from clinical material upon examining for tuberculosis. There were examined 865 cultures of clinical material samples while examining for tuberculosis, in which signs of growth of contaminating microflora were revealed, as well as 316 cultures of clinical material samples obtained during examination for tuberculosis, in which signs of growth of non-tuberculosis mycobacteria (NTM) were detected. The material was collected from January 2016 to January 2019. Samples with signs of growth of contaminating microflora allowed to identify 1,093 strains, samples with signs of growth of NTM 352 strains. Among them, the number of representatives of the genus Streptomyces comprised 39 strains. All Streptomyces strains were isolated from sputum. Variety of isolated Streptomyces: S. phaeochromogenes (13 strains), S. albus (1 train), S. avidinii (1 strain), S. badius (2 strains), S. chartreusis (2 strains), S. griseus (1 strain), S. hirsutus (2 strains), S. lavendulae (3 strains), S. violaceoruber (10 strains). Species identification was not possible for 4 strains. Analyzing the data obtained, it is possible to draw a conclusion about the moderate distribution of representatives of the genus Streptomyces in pattern of contaminating microflora while examining for tuberculosis. In pattern structure of isolated microorganisms, Streptomyces accounted for 3.3%. Among the microflora isolated from culture with signs of NTM growth, Streptomyces was presented by single strains. However, it should be noted that Streptomyces was the dominant group among acid-resistant actinomycetes in pattern of contaminating microflora and accounted for 38.3%. Taking into account the fact that a significant proportion of them were isolated as microbial associations, it can be concluded that Streptomyces turned out to be classical contaminants in this case. Nevertheless, we believe that the isolation of Streptomyces in association with clinically significant NTMs can be considered as an unfavorable factor due to the fact that antibiotic resistance genes are widespread among Streptomyces and may be transmitted to other types of microorganisms from the group of acid-resistant actinomycetes, including mycobacteria. Thus, the clinical material examining for tuberculosis is an interesting research object from which various representatives of acid-fast actinomycetes, including Streptomyces, can be isolated.

Bacteria of the genus Streptococcus are one of the most numerous and diverse representatives in the normal biocenosis of human organs and systems particularly being abundant as obligatory inhabitants of the oral cavity. All streptococci are divided into six groups: S. mitis, S. anginosus, S. salivarius, S. mutans, S. bovis and S. pyogenes, among which their certain number may potentially participate in the infectious process of developing periodontitis. Owing to the presence of a wide range of adhesion, invasion and colonization factors, they are capable of performing a protective function such as colonization resistance, but they may also cause formation of a pathological process in the tooth tissues and dento-facial system. The most prominent adhesion factors are antigens I/II (Ag I/II), fibronectin, collagen, laminin, fibrinogen binding proteins, serine-rich glycoproteins, pili, protein M, proteases, C5a peptidases, and the presence of a tooth capsule. Among the complex of proteolytic enzymes, it is important to note that streptococci contain enzymes hyaluronidase and lyase, which cleave the β1,4 bond between N-acetylglucosamine and d-glucuronic acid as the components of hyaluronic acid being a part of the connective tissues. The members of the S. anginosus group are able to release chondroitin sulfatase, which destroys chondroitin sulfates as specific components in cartilage, ligaments and other connective tissue structures. The enzymes noted contribute to a deeper spread of microorganisms in host tissues. Pathological processes associated with the development of periodontitis comprise a complex problem, wherein several important elements take part, including an infectious agent, a macroorganismal response in the form of nonspecific and adaptive immunity, as well as involvement of anti-inflammatory components. A great number of studies in research literature are dedicated to describe to participation of the members within the “red”, “orange” and “green” complexes as the principal components in developing periodontitis. Whereas the “yellow” and the “purple” complex play a more protective role by acting as antagonists while interacting with periodontopathogens, but it should not be ruled out a potential participation for some representatives, particularly S. intermedius, S. gordonii, A. odontolyticus, A. naeslundii in developing periodontal disease. Altogether, it poses a problem, which may be solved solely based on a multidisciplinary approach by inviting not only dentists and bacteriologists but also researchers of other specialties. Here we review the studies found in international and national data bases such as Scopus, Web of Science, Springer, RSCI.

Non-tuberculous mycobacteria (NTM) include more than 190 species and subspecies. Some NTM species can cause human diseases of the lungs or extrapulmonary infections. The guidelines focus on pulmonary mycobacteriosis in adult patients without cystic fibrosis or HIV infection caused by the most common NTMs, such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among slow-growing NTMs and Mycobacterium abscessus complex among fast-growing species. Experts of American Thoracic Society (ATS), European Respiratory Society (ERS), European Society for Clinical Microbiology and Infectious Diseases (ESCMID), and American Society for Infectious Diseases (IDSA) contributed to the development of the guidelines. A total of 31 evidence-based recommendations are provided for the diagnosis and treatment of NTM-induced lung infections.

Recently, more and more scientific works have been devoted to non-tuberculous mycobacteria, both by domestic and foreign researchers. One of the main reasons for this is the increase in patients with immunosuppression of various origins, improvement of the quality of laboratory and instrumental diagnostics of mycobacteriosis. This article focuses on the representatives of the M. fortuitum group, as the main pathogens among the group of fast-growing mycobacteria. The data on the modern classification based on the use of molecular genetic studies are indicated. The M. fortuitum group includes: Mycobacterium fortuitum, M. peregrinum, M. senegalense, M. porcinum, M. houstonense, M. neworleansense, M. boenickei, M. conceptionense, M. septicum, M. alvei. According to the new data, mycobacteria were divided into 5 clades (Abscessus-Chelonae, Fortuitum-Vaccae, Terrae, Triviale, Tuberculosis-Simiae), and based on molecular genetic studies, new genera in the Mycobacteriaceae family were isolated: Mycolicibacter spp., Mycolicibacillus spp., Mycolicibacillus spp., Mycobacteroides spp., Mycolicibacterium spp. In accordance with the new classification, representatives of the Mycobacterium fortuitum group belong to the genus Mycolicibacterium. The main epidemiological features of the main sources of the spread of mycobacteria, factors and ways of their transmission are indicated. Due to their wide distribution in the environment, representatives of the M. fortuitum group are capable of causing diseases of the pulmonary and extrapulmonary localization. The distinctive features of pathogenicity factors, due to which the course of the disease is determined, are noted. The article also indicates the main difficulties and features of determining the sensitivity to antimicrobial chemotherapy drugs, provides data on the main features of antibiotic resistance of M.fortuitum group. In preparing the review, literature sources obtained from international and domestic databases were used: Scopus, Web of Science, Springer, RSCI.