Objective: to evaluate and compare the qualitative and quantitative composition of the intestinal microbiota in patients with malignant neoplasms of various localizations. Material and Methods. The study included patients who received different types of treatment in N.N. Blokhin Oncology Research Center, Moscow, Russia in 2023 for gastric cancer, including cardioesophageal adenocarcinoma (group 1), esophageal squamous cell carcinoma (group 2) and metastatic or locally advanced melanoma of the skin (group 3). All patients had to have morphologic verification of the diagnosis at the time of inclusion, be over 18 years old, have an ECOG performance status of ≤1, and have no evidence of intestinal infection, as well as not take antibiotics within 28 days prior to entry into the study. Stool samples were collected during patients’ hospitalization. The quantitative and qualitative composition of microorganisms of 17 taxonomic groups was evaluated. Microorganisms were cultured according to standard microbiological methods, taking into account the growth conditions of a particular group of microorganisms. Species identification of microbial isolates was obtained by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF) and MALDI Biotyper v.3.0 software (Bruker daltonics, Germany). Descriptive statistics methods from the SPSS Statistics, v.27 software package were used. To quantitatively describe the species diversity of the gut microbiota, calculations were performed using the Margalef species richness index (d) and Shannon’s (H) diversity index. The criterion of uniformity of microbial species distribution according to their abundance in the population community was evaluated using the Pielow index (E). The Hutcheson’s T-criterion was used to test the significance of differences between sample sets of Shannon index values and to obtain statistically correct estimates of differences (p≤0.05). Results. A total of 63 samples of biological material (feces) were investigated. A change in the quantitative composition of intestinal microbiota in all study groups was found, which may have a negative impact on the general condition of the patient and the effectiveness of antitumor treatment. The increase in the proportion of Proteobacteria (Enterobacterales) can be considered as a risk factor for the development of infectious complications caused by Gram-negative microorganisms. The analysis of factors influencing the taxonomic diversity of intestinal microbiota revealed no significant differences in the composition of intestinal microbiota between the groups of patients with malignant tumors of different nosological forms (p>0.05).

Aim. To present data on the structure of bacterial pathogens causing infectionsin cancer patients atthe N.N. Blokhin National Research Center of Oncology and analyze them in comparison with data of domestic and foreign literary sources. Materials and methods. The data of 11,853 microorganisms isolated from patients hospitalized in the N.N. Blokhin National Research Center of Oncology in 2023 were analyzed. Results . Bacteria accounted for 90.0 % of all isolated microorganisms and only 10.0 % were fungal pathogens. Despite the fact that gram-negative pathogens have given way to gram-positive pathogens in absolute numbers, gram-negative microorganisms (60.7 %) still prevail in “clinically significant” biomaterials (blood, spinal fluid, urine, wound discharge, BAL, etc.), primarily Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and others. With the exception of Escherichia coli, a high percentage of carbapenem-resistant strains is noted for other pathogens: Klebsiella pneumoniae – 34 %, Pseudomonas aeruginosa – 50 %, Acinetobacter baumannii – 69 %. Real-time polymerase chain reaction revealed the leading carbapenemases: in Klebsiella pneumoniae strains – KPC or OXA-48 carbapenemases were detected in 55 % of cases, and NDM metallo-β-lactamasesin 45 %; in Pseudomonas aeruginosa strains – VIM metalloβ-lactamases were registered in 29 % of cases. Among gram-positive microorganisms, the most problematic is vancomycinresistant Enterococcus faecium. It accounts for 45 % of all E. faecium strains. Conclusion. Along with modern diagnostics and infection control measures, knowledge of the leading microbiota in a particular clinic will prevent the spread of infection and provide timely medical care to patients.

Работа посвящена редко встречающимся бактериальным и грибковым возбудителям инфекций. Эти микроорганизмы создают трудности в диагностике и лечении в связи с возможными ошибками идентификации возбудителя, природной или приобретенной лекарственной резистентностью.Возбудители редких инфекций могут колонизировать больных, образовывать биопленки, персистировать в окружающей среде, передаваться от больного к больному и приводить к развитию вспышек инфекции. Они нередко ухудшают прогноз лечения онкологического больного и приводят к летальному исходу.Информация об особенностях редко встречающихся микроорганизмов и возможных подходах к их лечению позволит врачам-онкологам оказывать своевременную квалифицированную помощь подобным пациентам.

Aim . To investigate the species composition and frequency of opportunistic pathogens in cancer patients diagnosed with non-small cell lung cancer (NSCLC) receiving chemotherapeutic treatment at the Federal State Budgetary Institution National Medical Research Center of Oncology named after N. N. Blokhin of the Russian Ministry of Health. Materials and methods . A prospective open single-center study included a cohort of patients with locally advanced or metastatic NSCLC receiving drug antitumor therapy, aged 18 years and older. The study was observational in nature. The endpoint of this phase of the study was to determine the relative number of NSCLC patients with chronic infection (pneumocystis, herpes simplex virus (HSV) 1, HSV-2, cytomegalovirus (CMV), Epstein–Barr virus (EBV), human herpes virus type 6 (HHV-6) and their combinations). Results. Antibodies to herpes viruses and/or pneumocystis were detected in patients (n = 18) diagnosed with NSCLC in 100 % of cases. Antibody titers corresponding to active infection were more characteristic for EBV and CMV, with CMV infection markers more often registered in titers corresponding to the acute stage of the disease, and EBV – in the reactivation stage without obvious clinical manifestations. In most cases, mixed infection with different pathogens was determined: combination of HSV-1 + EBV + CMV was found in 55.5 % (n = 10) of NSCLC patients; HSV-1 + EBV + CMV + HHV-6 – in 33.3 % (n = 6) of cases, HSV-1 + HSV-2 + EBV + CMV – in 5.5 % (n = 1), HSV-1 + HSV-2 + EBV + CMV + HHV-6 also in 5.5 % (n = 1) of patients. During bronchoalveolar lavage examination, pneumocystis were detected in 3 (42.8 %) out of 7 examined patients. Conclusion . Based on the results of studies of a relatively small cohort of patients in the absence of clinical symptoms of infection in NSCLC patients, a high percentage of IgM and IgG antibodies, which are markers of opportunistic infections and their combinations, were detected. Pneumocystis was isolated from bronchoalveolar lavage in 42.8 % of cases. It is necessary to evaluate the results obtained in a larger number of patients to determine approaches to the prevention and treatment of opportunistic infections.

Objective . To conduct a systematic analysis of data on the results of studies published in scientific journals on the pro-carcinogenic and anticarcinogenic role of microbiota, as well as on the therapeutic potential of microorganisms in oncogenesis. Material and Methods . The articles were searched using the Web of Science, Scopus, PubMed, Medline, and eLIBRARY databases. More than 150 sources dedicated to the study of the carcinogenic function of the microbiota and the possible influence of its species and quantitative composition on the efficacy and toxicity of antitumor therapy were found. Data from 71 articles were included in the review. Results . The relationship between the gut microbiota and cancer is multifactorial and bilateral: pro-carcinogenic on the one hand and anti-carcinogenic on the other hand. Microorganisms can induce tumor growth and cancer development through DNA damage and induction of mutagenesis, trigger oncogenic signals, disruption of barrier function, as well as immune response system disruption. Depletion of microbiota, the development of dysbiosis and induction of chronic inflammatory state are negative factors in the development of cancer. The anticancer effect of microorganisms is presumably based on the production of tumor-suppressive metabolites that function through multiple immune reactions. Maintenance of barrier function, competitive exclusion of pathogenic bacteria, and direct action on immune cells to prevent inflammation are also important protective factors. The presence of intratumor microorganisms in various tumors has been noted. Changes in species and quantitative composition of cancer patients’ microbiota are influenced by diet, taking antibacterial drugs, chemo-, immuno- and radiation therapy. In turn, the microbiota can affect the ongoing treatment. Numerous studies on the influence of the gut microbiota on the efficacy of immunotherapy, particularly in disseminated melanoma, have been conducted. It has been suggested that primary resistance to immunotherapy may be related to the abnormal composition of the gut microbiota. The level of gut microfora composition diversity and the number of Faecalibacterium or Bacteroidales in the fecal microbiota have been suggested to be the predictor of response to anti-PD-1 therapy. To change the composition and activity of the gut microbiota, several therapeutic methods, such as the administration of prebiotics, probiotics, synbiotics, postbiotics, fecal microbiota transplantation, as well as the change in the microbiota composition through a specific diet, are available.

The aim of the study was to determine the main Candida species isolated from blood of cancer patients, to compare the taxonomic structure of strains obtained from children and adults with candidemia. In total, during the study period, candidemia was microbiologically proven by blood culture in 81 patients (duplicates were excluded). Patients in the intensive care unit (ICU) accounted for 35,8%. The total number of isolates elaborated was 82 strains of 10 Candida species. In general, in the taxonomic structure of candidemias, C. parapsilosis (61.0%) predominates, C. albicans (20.7%) is in the second place, followed by C. glabrata and C. lusitaniae (3.7% each); C. krusei, C. guilliermondii and C. tropicalis (2.4% each). C. parapsilosis was statistically significantly often isolated from blood compared to C. albicans (61.0% versus 20.7%, respectively, p<0.0001). Candidemia was statistically significantly more often detected in adults than in children (63.0% versus 37.0%, respectively, p<0.002). Moreover, in adults, C. parapsilosis was statistically significantly more often isolated from blood than C. albicans (70.6% versus 15.7%, respectively, p<0.0001). In children, there were no significant differences in the frequency of isolation of C. parapsilosis and C. albicans: the proportion of C. parapsilosis was 45.2%, C. albicans - 29.0%. Rare species were identified in 7.8% of cases in adults, and in 12.9% of cases in children without statistical difference (p>0.05). The proportion of Candida non-albicans during the study period was 79.3%, and C. parapsilosis is the main species in this group (76.9%).

Цель: представить литературные и собственные данные по распространенности карбапенемаз у микроорганизмов, вызывающих тяжелые инфекции у онкологических больных и дать сведения о предпочтительном лечении при выделении основных карбапенем-резистентных грамотрицательных возбудителей ( Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae ). Методы исследования: обзор литературы за последние 10 лет, включая международные рекомендации по лечению мультирезистентных инфекций (2021–2022 гг.). Также представлены собственные данные по частоте выделения карбапенемаз в биоматериалах от больных с нозокомиальными инфекциями, находившимися в НМИЦ онкологии им. Н. Н. Блохина, в 2021–2022 гг. Результаты: представлены обобщенные данные, касающиеся возможностей комбинированной терапии нозокомиальных инфекций, вызванных трудно поддающимися лечению возбудителями (карбапенемазопродуцирующими грамотрицательными микроорганизмами), дан подробный разбор механизмов резистентности, обусловленных бета-лактамазами (карбапенемазами). Заключение: При наличии тяжелых инфекций, сепсиса / септического шока универсальных схем антибиотикотерапии не существует. Необходимо знание особенностей лечения в зависимости от молекулярно-генетических характеристик возбудителей инфекции.

A research objective - to study tumor tissues of primary and recurrent patients with cancer of the oropharyngeal region for the frequency of occurrence of four types of anaerobic periodontogens and their associations by two methods: real-time PCR and cultural. There is speculation that bacteria can influence the pathogenesis of cancer. A comparative assessment of the content of four anaerobic periodontogens (Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, Treponema denticola) in the tumor tissue and in the healthy tissue of the oral mucosa of patients with oropharyngeal cancer was carried out. It was found that the identification of odontopathogens by the real-time PCR method is much more informative than the traditional culture method, with the exception of P. intermedia, for the identification of which the traditional culture method was more effective. In 33.3% of patients, both primary and secondary, the composition of microorganisms was the same in both healthy and tumor tissue. In 20% of primary patients and in 13.3% of repeat patients, no associations of microorganisms included in the study were found in healthy tissue. Associations of 4 bacteria were recorded only in tumor tissue in both primary and repeated patients, and in repeated patients - statistically significantly more often. In 53.3% of repeat patients, associations of 4 bacteria were recorded in tumor tissue, whereas in primary patients, only in one case. P. gingivalis from tumor tissue in repeat patients was statistically significantly more often than in primary patients. T. forsythensis in primary patients was found statistically significantly more often in healthy tissues than in repeat patients, in which T. forsythensis was found statistically significantly more often from tumor tissue than in healthy tissue). T. denticola in healthy tissue was detected in both primary and repeated patients in isolated cases. T. denticola in tumor tissue was found statistically significantly more frequently in both primary and repeated patients compared to healthy tissue. P. gingivalis, T. forsythensis, and T. denticola should perhaps be considered risk indicators indicating the level of significance of their associations with oropharyngeal cancer.

Relevance. The global trend of rapid increase in resistance to antifungal drugs due to multiple factors, dictates the need for continuous monitoring of taxonomic structure and susceptibility of nosocomial pathogens, causing invasive fungal infections, for permanent correction of the optimal prevention and treatment strategies. Purpose: to determine antifungal susceptibility of the main yeast pathogens in candidemia in cancer patients, as well as to determine resistance genes and pathogenic factor genes. Material and Methods. Eighty-two strains of Candida spp. isolated from blood of cancer patients from 2015 to 2021 were analyzed. Minimum inhibitory concentrations of fuconazole, voriconazole, posaconazole, anidulafungin and micafungin were determined by a gradient method (E-test, BioMerieux, France). The EUCAST and CLSI criteria were used for MIC value assessment. The genes, associated with pathogenicity factors, and resistance to antifungal drugs were identifed. Results. Our study results based on EUCAST 2020, v.10.0 criteria showed that triazoles, especially fuconazole, were the least effective drugs in empirical therapy for invasive candidiasis (including candidemia). Resistance of Candida spp. fuconazole was superior to that of voriconazole (47.2 % vs 23.2 %, respectively, p<0.01) and posaconazole (47.2 % vs 30.4 %, respectively, p><0.05). The highest in vitro activity was observed in echinocandins, and anidulafungin was 2 times more active than micafungin (4.1 % of resistant strains vs 11.4 %, respectively), with no statistically signifcant difference (p>0.05). The ERG11 and FKS1 genes associated with resistance to antifungal drugs were detected in 28.6 % of Candida spp. strains. The ERG11 gene was detected in 8.6 % of cases, exclusively in Candida albicans strains. The FKS1 gene was identifed in 20.0 % of strains (85.7 % of them were C. parapsilosis, 7.1 % each were C. tropicalis and C. glabrata). Pathogenic factor genes were identifed in 78.6 % of C. albicans and in 79.1 % of C. parapsilosis strains. Conclusion. Molecular genetic methods for the detection of Candida spp strains carrying resistance genes to antifungal drugs, and the determination of pathogenicity factors are promising trends in searching for biomarkers. They facilitate interpretation of results of microbiological study to assess the ability of Candida spp. strains to develop invasive mycoses.

Introduction. Interactions between the 2 microbiota components – bacteria and fungi – are of interest as diagnostic and prognostic markers in selection of treatment tactics for oncological patients.Aim. To study microbiota of the oral cavity in patients with primary squamous cell carcinoma of the oropharyngeal area before and after surgical intervention to find biomarkers for rational selection of antifungal drugs.Materials and methods. At the Surgical Department of Head and Neck Tumors of the N. N. Blokhin National Research Center of Oncology, three-component study was performed: investigations of spectrum of Candida spp. isolates, Candida spp. strains’ resistance to antifungals, and oral washes in primary patients before and after surgery. mALDI-Tof microflex LT (Biotyper, Bruker Daltonics, germany) was used for strain identification; Sensititre Yeast ONE, YO10 (Trek Diagnostic System, united kingdom) plates were used for determination of minimal inhibiting concentrations of anti fungals. values of minimal inhibiting concentrations were evaluated based on the European Committee on Antimicrobial Susceptibility Testing (EuCAST) criteria (version 10.0).Results. four-year observation of patients at the surgical department of head and neck tumors of the N. N. Blokhin National Research Center of Oncology showed that the most common species of Candida is C. albicans (73.5 % of cases). Candida spp. resistance to antifungals was detected only for fluconazole (9.3 % of cases) and micafungin (8.0 % of cases), mostly among C. albicans strains. In 31.8 % of primary patients, oral washes prior to surgery showed growth of Candida spp. (probably, tissue colonization). After surgical intervention, Candida spp. growth was detected in 36.4 % of cases, only 1 of which was diagnosed as invasive mycosis. In 54.5 % of cases before and in 72.7 % of cases after surgery, gram-negative rods were detected. After surgical intervention, percentage of enterobacteria and non-fermenters significantly increased: 59.1 % versus 27.3 % (p <0.05) and 63.6 % versus 27.3 % (p <0.02), respectively. prior to surgery, non-fermenting gram-negative bacteria were represented only by P. aeruginosa; after surgery, the spectrum of non-fermenting gram-negative bacteria became wider but percentage of P. aeruginosa remained high: 71.4 %. ERG11 gene was identified only in 1 strain: C. albicans. FKS1 gene also was identified only in 1 strain: C. inconspicua. virulence factor genes were detected in 57.1 % of strains.Conclusion. Surgical intervention is associated with changes in bacterial microbiota but not fugal microbiota. presence of virulence factor genes and resistance genes in Candida spp. strains should be considered a biomarker allowing to differentiate between colonization and candida infection and can be used for rational selection of antifungal drugs in prevention and treatment of invasive candidiasis, especially in the absence of criteria for interpretation of measured minimal inhibiting concentrations of antifungals.

Introduction. Currently, there is no global consensus regarding the management of breast cancer patients with implant-associated infections. Some studies clearly recommend their removal and surgical debridement with consecutive antimicrobial treatment, while others prefer long-term antibacterial therapy (at least 1 month) with the effectiveness of such conservative approach of 36–73 %.Case description. A 43-year-old patient suffering from brca1-positive right breast cancer t2n0m0 (invasive carcinoma of non-specific type g3, er – 8, pgr – 0, her-2/neu – 0, ki67 (%) – less than 20 %), underwent radical skin-preserving mastectomy on the right with simultaneous implant reconstruction and preventive subcutaneous mastectomy on the left with simultaneous implant reconstruction. Peri-implant infection in the left breast was observed on the 21st day after surgery.Results. The patient received empirical therapy with cefepim. Microbiological examination of the punctate revealed the causative agent of infection – methicillin-resistant staphylococcus aureus (mrsa) (1×105cfu/ml). Daptomycin 6 mg/kg/day was added to therapy. After 8 weeks, the patient received oral moxifloxacin 400 once daily, for another 3 weeks. A complete response was achieved. The patient has no signs of infection for 3 years.Conclusion. Long-term etiotropic antibacterial therapy with daptomycin followed by oral moxifloxacin resulted in a stable clinical effect.

The purpose of the study: to compare the activity of vancomycin, teicoplanin and linezolid and to determine their place in the current treatment of nosocomial infections caused by gram-positive microflora.Material and Methods. 640 gram-positive microorganisms (S. aureus, E. faecium, E. faecalis) isolated in 2018 from various pathological materials from cancer patients treated at N.N. Blokhin National Medical Research Center of Oncology were studied. Literature data from 1982 to 2019, concerning efficacy of glycopeptides (vancomycin, teicoplanin) and linezolid against these pathogens were analyzed.Results. Data analysis showed that percentage of methicillin-resistant Staphylococcus aureus (MRSA) was 89 % and percentage of vancomycinresistant enterococci (VRE) was 5.1 % among Enterococcus faecalis and 16.4 % among Enterococcus faecium. The susceptibility of the studied gram-positive microorganisms to teicoplanin, vancomycin and linezolid ranged from 83.3 to 98.8 % (p>0.5). In general, teicoplanin, vancomycin, and linezolid had equally high microbiological activity against nosocomial strains of S. aureus and Enterococcus spp. Also, according to the literature data, a comparative assessment of the clinical effectiveness and cost-effectiveness of glycopeptides and linezolid was assessed.Conclusion. Vancomycin and teicoplanin are still the main drugs for the treatment of various infections caused by resistant gram-positive microflora. However, teicoplanin, with an efficacy equal to that of vancomycin, has a number of significant advantages over the latter: better tolerability, lower frequency of adverse reactions, and pharmacokinetic features that make it possible to use it once a day both intravenously and intramuscularly. Both drugs, along with linezolid, can be used to treat infections caused by gram-positive microorganisms in cancer patients.

Introduction. So far there has been no clear protocol on the treatment of bacterial infections in hematopoietic cancer patients undergoing polychemotherapy (PCT) and hematopoietic stem cell transplantation (HSCT). Guidelines available from antibiotic therapy panels such as EMBT, NCCN, ECIL, Sepsis-3 often fail to cover the entire spectrum of clinical risk factors of severe complications caused specifically by multiresistant Klebsiella pneumoniae.The aim of the study — is to showcase the clinical experience of demonstration of the experience of the Research Institute of Pediatric Oncology and Hematology at N.N. Blokhin Russian Cancer Research Center with respect to adjusting antibacterial therapy for the spectrum of microorganisms found in the patient before the onset of antitumor therapy, and for the multiresistant microorganism findings in patients with blood cancers and febrile neutropenia (FN) undergoing PCT and HSCT.Materials and methods. The study involved five patients undergoing either PCT or HSCT for hematopoietic cancers at Research Institute of Pediatric Oncology and Hematology in October 2019 — October 2020, multiresistant Klebsiella pneumonia colonies found in each case. Results. Five patients with hematopoietic cancers and induced bone marrow aplasia were found to have multiresistant Klebsiella pneumoniae colonies on top of post-PCT/HSCT immunosuppression. Given high risk of death, these patients need early antibacterial therapy with reserve antibiotics outside standard empirical antibacterial treatment protocols should they develop FN. The Center's practices have shown that baseline protocols are often inadequate to the severity of these patients' conditions in a certain timeframe.Conclusions. To sum up the Center's limited experience, the finding is that additional research is required into the factors of risk of severe multiresistant Klebsiella pneumoniae infections in patients undergoing PCT and HSCT; algorithms must be developed for the treatment of patients in such a critical condition.

Introduction. The associative role of the bacterial factor in the development of both primary malignant tumors of the oral mucosa and relapses is being actively discussed today. In the article published earlier, we have already described the possible mechanisms of action of periodontopathogenic microflora and its connection with the development of squamous cell carcinoma of the oral mucosa through cell proliferation, intracellular accumulation of pathogen, DNA replication and affect the signaling pathways of MARK (mitogen-activated protein kinase).Objective – to analyze the impact of periodontal pathogens on the risk of oral squamous cell carcinoma and its recurrence, as well as to evaluate the role of polymerase chain reaction and bacterial culture in the diagnosis of squamous cell carcinoma.Materials and methods. This study included 35 patients with stage Т3–4 squamous cell carcinoma, whose tumor tissue samples were tested for periodontal pathogens using culture and PCR. We analyzed 5 paraffin-embedded and 30 frozen tissue blocks from newly diagnosed (n = 15) and re-treatment (n = 15) patients.Results. We found that PCR was more sensitive than culture for the detection of possible etiological agents and predictors of squamous cell carcinoma (including Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) (р <0.001). For example, Tannerella forsythia and Treponema denticola were detected only using PCR, whereas all cultures were negative. However, conventional culture proved to be more effective than PCR for the detection of Prevotella intermedia. Between 3 % and 100 % of newly diagnosed patients tested positive for Treponema denticola and some other periodontal pathogens (PCR) developed relapses, whereas among re-treatment patients, this proportion was 66.6 %.Conclusion. The combination of the culture method and the polymerase chain reaction method in the study of periodontopathogenic microflora has shown high efficiency in identifying possible predictors of squamous cell carcinoma of the oral mucosa and in preventing the development of chronic infectious periodontal diseases.

The objective of the study was to analyze the taxonomic structure of urinary infection pathogens and determine the susceptibility of ESKAPE group microorganisms (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus spp.) isolated from cancer patients with nosocomial infections in 2018—2020 to antimicrobials.Materials and methods. 413 (71.9 %) strains of ESKAPE group bacteria from 228 patients were studied. Microorganisms were identified and antibiotic resistance was determined using Vitek-2 System (France) and MicroScan WalkAway (Germany / USA) analyzers.Results and conclusion. All gram-positive microorganisms were highly sensitive to vancomycin and teicoplanin, linezolid, tigecycline, and daptomycin, which can be used in the treatment if clinical indications are seen. Among gram-negative bacteria, the percentage of ESBL producers was 60—70 %, the percentage of carbapenem-resistant bacteria was minimalfor E. coli, rnmpared to the rest - 40—50 %, demonstrating the need to limit the use of carbapenems in the clinic.

The study objective is to evaluate the effect of periodontal microorganisms on development of squamous-cell carcinoma of the oral mucosa and the risk of its recurrence.Materials and methods. Microbiological study of biomaterials from 150 patients was performed. The study group included 100 patients with T3–T4 squamous-cell carcinoma of the oral mucosa and was subdivided into two subgroups with 50 patients in each. The control group included 50 patients.Results. Analysis of the results obtained in the subgroup of primary patients showed the following trends: in 2 (50 %) of 4 patients with Fusobacterium spp., recurrence of the main disease was observed as well as a case of distant metastasis into the bones. Among 35 patients with Prevotella spp. in the biomaterials, in 16 (45.7 %) recurrence of the tumor was observed. Among 10 patients with Veillonella spp., recurrence was observed in 20 %. The most common aerobic microorganism was Streptococcus spр. Among patients who underwent treatment at the N.N. Blokhin National Medical Research Center of Oncology, recurrence was diagnosed in 28.5 %, distant metastases in 4.7 %. In the subgroup of repeat patients, the following trends were observed: among 27 patients with Fusobacterium spp., recurrence of the main disease was observed in 63 %. Among 26 patients with Prevotella spp. in the biomaterial, in 11 (42.3 %) local recurrence was observed. Among 24 patients with Veillonella spp., recurrence developed in 33.3 %. The most common aerobic microorganism was Streptococcus spр., recurrences developed in 21 % of cases.

Purpose of the study. To conduct typing of toxigenic strains of Clostridium difficile, obtained from oncological patients who are in hospital.Material and Methods. The study included 130 patients with Clostridium difficile – associated diarrhea. First, the presence of toxins A+B+ in the feces was determined by enzyme immunoassay on an automatic miniVidas analyzer from BioMieux SA (France). For screening using real-time PCR, 26 toxigenic Clostridium difficile were selected. For the study used the system GeneXpert company «Cepheid» (Sweden).Results. Of the 1287 patients with diarrhea who were treated in an oncologic hospital, 130 (10,1%) tested positive for toxin A+B+ Clostridium difficile. For the study using real-time PCR, 26 samples were taken. The average age of patients is 57 years. 10 (38,5%) toxigenic strains were identified as hypervirulent ribotype. 7/10 strains were isolated for 3 consecutive month. The average age of patients with hypervirulent strains was 45 years. Patients participating in the study, in most cases were from the surgical departments – 61,5%, from the therapeutic – 34,7%.Conclusion. The study showed that the prevalence of Clostridium difficile infection in our clinic is lower than in other countries. Although hypervirulent strains accounted for 1/3 of all typed Clostridium difficile, special attention should be paid to them. Delayed diagnosis, delay in the onset of specific therapy in cancer patients can lead to a deterioration in the quality of life and in some cases be fatal. PCR diagnostics can determine the hypervirulent ribotype and carry out epidemiological measures aimed at preventing local outbreaks in the hospital.

The purpose of the study : to compare the activity of vancomycin, teicoplanin and linezolid and to determine their place in the current treatment of nosocomial infections caused by gram-positive microflora. Material and Methods . 640 gram-positive microorganisms (S. aureus, E. faecium, E. faecalis) isolated in 2018 from various pathological materials from cancer patients treated at N.N. Blokhin National Medical Research Center of Oncology were studied. Literature data from 1982 to 2019, concerning efficacy of glycopeptides (vancomycin, teicoplanin) and linezolid against these pathogens were analyzed. Results . Data analysis showed that percentage of methicillin-resistant Staphylococcus aureus (MRSA) was 89 % and percentage of vancomycinresistant enterococci (VRE) was 5.1 % among Enterococcus faecalis and 16.4 % among Enterococcus faecium. The susceptibility of the studied gram-positive microorganisms to teicoplanin, vancomycin and linezolid ranged from 83.3 to 98.8 % (p>0.5). In general, teicoplanin, vancomycin, and linezolid had equally high microbiological activity against nosocomial strains of S. aureus and Enterococcus spp. Also, according to the literature data, a comparative assessment of the clinical effectiveness and cost-effectiveness of glycopeptides and linezolid was assessed. Conclusion . Vancomycin and teicoplanin are still the main drugs for the treatment of various infections caused by resistant gram-positive microflora. However, teicoplanin, with an efficacy equal to that of vancomycin, has a number of significant advantages over the latter: better tolerability, lower frequency of adverse reactions, and pharmacokinetic features that make it possible to use it once a day both intravenously and intramuscularly. Both drugs, along with linezolid, can be used to treat infections caused by gram-positive microorganisms in cancer patients.

Introduction. Penile cancer (pc) is a rare cancer. The standardized incidence rate of pc in russia is 0.82 cases per 100,000 males. On average, 58 % of patients (20–96 %) with pc have a local infection process: tumor decay, the presence of erosion, tumor ulceration, inflammatory changes in regional lymph nodes, etc. During hospitalization nosocomial pathogens may be possible causes of infection in ulcerative lesions.The aim of the study was to present the results of the treatment of tumor ulcer in a patient with penile cancer infected with multiresistant acinetobacter baumannii and klebsiella pneumoniae.Material and methods. We present a clinical observation of 54-year-old patient diagnosed with penile cancer pt4n3m0, with ulceration of the tumor, localized at the root of the penis and ulceration of metastatic lymph nodes in the left inguinal region and subsequent infection with highly resistant nosocomial microorganisms.Results. The patient received 6 courses of paclitaxel, ifosfamide and cisplatin with clinical effect, such as significant reduction of the tumor and therapeutic pathomorphosis of 3-rd degree. Then ileo-inguinal lymphadenectomy was performed on the left. A few months later the tumor continued to grow in the left groin area. During the 2nd line of chemotherapy (cisplatin, docetaxel and capecitabine), the patient had grade iii–iv neutropenia, febrile neutropenia. High fever and localized infection in the area of tumor ulceration with multiresistant hospital microorganisms was detected. Combined antibiotic therapy had temporary effect. After isolation of multiresistant carbapenemresistant k. Pneumoniae from the ulcer, the patient was prescribed ceftazidim/avibactam 2.5 g 3 times a day. Clinical effect, such as defervescence and significant reduction of the ulceration zone was seen subsequently.Conclusion. Etiotropic antibacterial therapy of the infected tumor ulcer resulted in a significant reduction in the manifestation of the infection process, allowing antitumor therapy to be continued, as well as surgery to be performed.