On the possibility of photodynamic inactivation of tracheobronchial tree pathogenic microbiota using methylene blue (in vitro study).

BACKGROUND: The treatment of patients after mechanical ventilation of lungs suffering from a multi-species infection of the tracheobronchial tree can be complicated.. The situation is aggravated in patients with post-intubation tracheal stenosis, where infection plays a leading pathogenetic role in damage to the tracheal wall. As a result of such a pathological process, cicatricial stenosis of the trachea of purulent-inflammatory infectious genesis or infected tracheal stenosis (ITS) may occur. METHODS: In this work, we studied the possibility of photodynamic inactivation of pathogenic microbiota typical for patients with ITS using methylene blue (MB) as a photosensitizer. RESULTS: 13 clinical isolates of 8 species of bacteria from 9 patients were susceptible to photodynamic inactivation with MB. 30 µM of MB at a light irradiation dose of 25 J/cm2 and incubation with MB for 15 min allows to completely inactivate bacteria found in the tracheobronchial secretions of patients with ITS. CONCLUSIONS: MB retains its optico-physical properties in the range of 3-30 µM and provides effective inactivation of isolated Gram-positive and Gram-negative bacteria, including multi- and pan-resistant to antibiotics.

Microbiological Characteristics of Some Stations of Moscow Subway.

The subway is one of the most actively used means of transport in the traffic infrastructure of large metropolitan areas. More than seven million passengers use the Moscow subway every day, which promotes the exchange of microorganisms between people and the surrounding subway environment. In this research, a study of the bacterial communities of two Moscow subway stations was conducted and the common subway microbiome was determined. However, there were differences in microbiological and antibiotic-resistance profiles, depending on the station. The station's operational period since opening correlated with the taxonomic diversity and resistance of the identified bacteria. Moreover, differences between aerosol and surface bacterial communities were found at the two subway stations, indicating the importance of diversified sampling during the microbiome profiling of public areas. In this study, we also compared our data with previously published results obtained for the Moscow subway. Despite sample collection at different stations and seasons, we showed the presence of 15 common genera forming the core microbiome of the Moscow subway, which represents human commensal species, as well as widespread microorganisms from the surrounding environment.

A Strategy for the Rapid Development of a Safe Vibrio cholerae Candidate Vaccine Strain.

Approximately 1/6 of humanity is at high risk of experiencing cholera epidemics. The development of effective and safe vaccines against Vibrio cholerae, the primary cause of cholera, is part of the public health measures to prevent cholera epidemics. Natural nontoxigenic V. cholerae isolates represent a source of new genetically improved and relatively safe vaccine strains. However, the genomic engineering of wild-type V. cholerae strains is difficult, and these strains are genetically unstable due to their high homologous recombination activity. We comprehensively characterized two V. cholerae isolates using genome sequencing, bioinformatic analysis, and microscopic, physiological, and biochemical tests. Genetic constructs were Gibson assembled and electrotransformed into V. cholerae. Bacterial colonies were assessed using standard microbiological and immunological techniques. As a result, we created a synthetic chromoprotein-expressing reporter operon. This operon was used to improve the V. cholerae genome engineering approach and monitor the stability of the genetic constructs. Finally, we created a stable candidate V. cholerae vaccine strain bearing a recA deletion and expressing the ß-subunit of cholera toxin. Thus, we developed a strategy for the rapid creation of genetically stable and relatively safe candidate vaccine strains. This strategy can be applied not only to V. cholerae but also to other important human bacterial pathogens.

DETECTION OF OPHIDIOMYCES OPHIDIICOLA IN THREE FILE SNAKES (ACROCHORDUS GRANULATUS) IMPORTED FROM INDONESIA TO THE MOSCOW ZOO (RUSSIA).

Three file snakes (Acrochordus granulatus) were delivered to the Moscow Zoo (Russia) from Jakarta (Indonesia). Shortly after arrival, multiple white blisters were detected on their bodies. All three snakes died within a month of arrival. On microscopy, arthrospores and mycelium were seen in exudate from the lesions. Ophidiomyces ophidiicola was isolated from two of three snakes and identified by internal transcribed spacer sequencing. Dermatophyte test medium turned red in positive cultures and can be potentially employed for detection of O. ophidiicola, the causative agent of snake fungal disease. This is the first report of O. ophidiicola in Russia and the second reported case of ophidiomycosis in file snakes. The possible source of O. ophidiicola in snakes imported from Southeast Asia is discussed.

Virtual Screening for Potential Inhibitors of CTX-M-15 Protein of Klebsiella pneumoniae.

The Gram-negative bacterium Klebsiella pneumoniae, responsible for a wide variety of nosocomial infections in immuno-deficient patients, involves the respiratory, urinary and gastrointestinal tract infections and septicemia. Extended spectrum ß-lactamases (ESBL) belong to ß-lactamases capable of conferring antibiotic resistance in Gram-negative bacteria. CTX-M-15, a prevalent ESBL reported from Enterobacteriaceae including K. pneumoniae, was selected as a potent anti-bacterial target. To identify the novel drug-like compounds, structure-based screening procedure was employed against downloaded drug-like compounds from ZINC database. An acronym for "ZINC" is not commercial. The docking free energy values were investigated and compared to the known inhibitor Avibactam. Six best novel drug-like compounds were selected and their hydrogen bindings with the receptor were determined. Based on the binding efficiency mode, three among these six identified most potential inhibitors, ZINC21811621, ZINC93091917 and ZINC19488569, were predicted as potential competitive inhibitors against CTX-M-15 compared to Avibactam. These three inhibitors may provide a framework for the experimental studies to develop anti-Klebsiella novel drug candidates targeting CTX-M-15.