Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial transmission and invasive infections with high mortality. This study aimed to investigate the genetic relationships, enzymatic activities, and drug-resistance profiles of C. auris isolates to evaluate the population and epidemiological diversity of candidiasis in Russia. A total of 112 clinical isolates of C. auris were analyzed from May 2017 to March 2023 in 18 hospitals across Saint Petersburg, the Leningrad Region, and Moscow. Species identification was confirmed by ITS sequencing, and genotyping was performed using 12 short tandem repeat (STR) markers. Antifungal susceptibility was tested using Sensititre™ YeastOne™ plates, and hydrolytic enzyme production was measured by the plate method. ITS sequencing confirmed that all isolates belonged to a single ITS cluster (clades I and III). Fifteen distinct STR genotypes were identified, with genotype I being dominant (n = 53). The most variable of the analyzed markers turned out to be M3-Ia, which was represented in the Russian population by eight different variants. Fluconazole resistance was found in 111 isolates, 17% were resistant to amphotericin B, and 3.6% to 5-flucytosine. Phospholipase activity was strong in most strains, especially in urine isolates (p = 0.014). Conclusion: The predominance of STR genotype I and its variability at the M3-Ia locus suggest its association with nosocomial outbreaks and transmissibility in Russia.

Relevance. In the last decade, there has been an increase in the isolation of antibiotic-resistant microorganisms in community settings. Colonization and asymptomatic carriage of extended-spectrum beta-lactamase and carbapenemase producers can be a precursor to the development of an infectious process and a significant factor in the pathogenesis of healthcare-associated infections. Understanding the risk factors for community-acquired colonization with antibiotic-resistant microorganisms is necessary for targeted screening and timely implementation of measures to prevent the spread of resistance in hospitals.The aim. To determine significant risk factors for colonization with antibiotic-resistant gram-negative microorganisms and carriage of carbapenem resistance genes in patients admitted to a multidisciplinary hospital.Materials & Methods. A prospective single-center crosssectional study was conducted at the Moscow Multidisciplinary Clinical Center «Kommunarka» from 15.09.2022 to 15.08.2023. The study included 733 patients aged 18 to 94 years. Biological samples were taken from the rectum, upper and lower respiratory tract. The obtained samples were examined by real-time polymerase chain reaction (PCR) with hybridization-fluorescent detection of amplification products to identify carbapenemase genes and by culture method to determine colonization with carbapenemresistant bacteria. Identification of isolated microorganisms was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. The results of susceptibility testing were interpreted based on EUCAST v12.0, v13.0, and v13.1 criteria.Results. Carriage of carbapenemase genes was detected in 12.6% of patients admitted to the hospital, while colonization with carbapenem-resistant bacteria was found in 2.7%. In the majority of patients (66.7%), the rectum was the only site of gene carriage. However, only 18.1% of these patients showed rectal colonization with carbapenem-resistant bacteria. This discrepancy is likely due to the higher sensitivity of molecular genetic methods compared to culture-based techniques. From a clinical perspective, the detection of nucleic acids by PCR can serve as an equivalent to pathogen detection in biological material. Multivariate analysis identified 5 independent predictors of colonization: cytostatic therapy, transfer from another hospital, need for vasopressor support, antibiotic use in the previous 3 months, and male gender.Conclusion. The identified risk factors allow for the identification of a highrisk patient cohort for targeted screening, enabling timely administration of appropriate antibiotic therapy and implementation of measures to prevent the spread of carbapenem resistance in the hospital.

COVID-19 is caused by an airborne virus, SARS-CoV-2. The upper respiratory tract (URT) is, therefore, the first system to endure the attack. Inhabited by an assemblage of microbial communities, a healthy URT wards off the invasion. However, once invaded, it becomes destabilised, which could be crucial to the establishment and progression of the infection. We examined 696 URT samples collected from 285 COVID-19 patients at three time-points throughout their hospital stay and 100 URT samples from 100 healthy controls. We used 16S ribosomal RNA sequencing to evaluate the abundance of various bacterial taxa, α-diversity, and β-diversity of the URT microbiome. Ordinary least squares regression was used to establish associations between the variables, with age, sex, and antibiotics as covariates. The URT microbiome in the COVID-19 patients was distinctively different from that of healthy controls. In COVID-19 patients, the abundance of 16 genera was significantly reduced. A total of 47 genera were specific to patients, whereas only 2 were unique to controls. The URT samples collected at admission differed more from the control than from the samples collected at later stages of treatment. The following four genera originally depleted in the patients grew significantly by the end of treatment: Fusobacterium, Haemophilus, Neisseria, and Stenotrophomonas. Our findings strongly suggest that SARS-CoV-2 caused significant changes in the URT microbiome, including the emergence of numerous atypical taxa. These findings may indicate increased instability of the URT microbiome in COVID-19 patients. In the course of the treatment, the microbial composition of the URT of COVID-19 patients tended toward that of controls. These microbial changes may be interpreted as markers of recovery.

Background. Carbapenem-resistant Enterobacteriaceae have a major impact on ICU-stay and treatment outcomes. Objective. To identify the risk factors of colonization by CPE (carbapenemase-producing Enterobacterales) in ICU patients. Material and methods. We enrolled 94 ICU patients between November 2020 and January 2021 and divided then into 3 groups: group 1 (n=63) — all patients not colonized by CPE, group 2 (n=31) — colonized upon admission, group 3 (n=31) — colonized after 5-day ICU-stay. All patients underwent microbiological and molecular genetic testing via real-time PCR (AmpliSens MDR MBL-FL and AmpliSens MDR KPC/OXA-48-FL reagent kits) of rectal smear samples. Results. We found CPEs in rectal smear samples that mainly released carbapenemases OXA-48, NDM, KPC and their combinations. Pre-hospital risk factors for intestinal colonization by CPE were identified: male gender (OR=0.28, CI 95% [0.11, 0.74], p=0.010), hospital-stay within previous 3 months (OR=4.22, CI 95 % [1.38; 12.9], p=0.011) and previous antimicrobial therapy (OR=2.23, CI 95% [0.76; 6.54], p=0.145). There were the following risk factors after 5-day hospital-stay: primary colonization (OR=15.64, CI 95% [4.64; 52.73], p<0.0001), female gender (OR=2.51, CI 95% [0.96, 6.56], p<0.059), age (OR=0.969, CI 95% [0.931; 1.007], p=0.112), use of vasopressors (OR=27.11, CI 95% [2.43; 302.11], p=0.007), CRP (OR=0.997, CI 95% [0.992; 1.001], p=0.162), central venous catheter (OR=3.56, CI 95% [1.36; 9.30], p=0.010), proton pump inhibitors (OR 0.38, CI 95% [0.13; 1.11], p=0.077). Conclusion. Early detection of CPE and carbapenemases and their monitoring are necessary to improve the effectiveness of antimicrobial therapy in ICU patients.

Lipoglycopeptide antibiotics are semi-synthetic derivatives of glycopeptides and are characterized by a pronounced bactericidal activity against gram-positive pathogens. The aim of the study was comparative assessment of the sensitivity of gram-positive clinical isolates to lipoglycopeptide antibiotics (telavancin, dalbavancin, oritavancin). The following isolates were included in the work: methicillin-resistant Staphylococcus aureus (MRSA, n=780), methicillin-resistant coagulase-negative Staphylococcus spp. (MRCoNS, n=163), and vancomycin-resistant Enterococcus faecium (VREf, n=93). Serial dilutions were used to assess sensitivity with the addition of 0.002% polysorbate 80 to the medium. Lipoglycopeptides showed more pronounced antibacterial activity against MRSA compared to vancomycin, teicoplanin, and daptomycin, and had a MIC₅₀/MIC₉₀ (µg/ml): for telavancin — 0.06 /0.125, for dalbavancin — 0.016/0.06, and for oritavancin — 0.06/0.125. A trend towards an increase in the MIC of lipoglycopeptides and daptomycin was established in MRSA with the MIC of 2 µg/ml for vancomycin, the proportion of which was 13%. For MRCoNS, MIC₅₀ and MIC₉₀ of lipoglycopeptides did not exceed 0.06 µg/ml and 0.125 µg/ml, respectively. Oritavancin showed strong activity against VREf at MIC range of 0.03 µg/ml to 0.5 µg/ml, and at MIC₉₀ of 0.25 µg/ml. Thus, lipoglycopeptide antibiotics are a plausible alternative to vancomycin and daptomycin; they are characterized by pronounced activity and can be used to treat severe forms of staphylococcal infections.