Адгезивные и инвазивные свойства токсигенных штаммов Corynebacterium diphtheriae Резюме Актуальность. В настоящее время известно, что токсигенные штаммы Corynebacterium diphtheriae способны не только к адгезии, но и инвазии в эпителиальные клетки верхних дыхательных путей. Помимо этого, коринебактерии обладают способностью к формированию биопленок, в составе которых они могут изменять в определенной мере свои свойства (размеры бактериальных клеток, антибиотикочувствительность), что может оказывать влияние на их адгезивные и инвазивные свойства.

Relevance. The incidence of the novel coronavirus infection is on the rise worldwide. To effectively combat COVID-19, both vaccination and control of the circulation of SARS-CoV-2 strains among the population and, especially, foreign citizens arriving in Russia from around the world are necessary. Aim. To determine the frequency of detection of SARS-CoV-2 RNA in foreign medical students vaccinated against COVID-19 with various vaccine preparations. Materials and methods. Foreign students (510 people) of a medical university aged 18-25 years, vaccinated against COVID-19, who arrived in Russia during June-August 2021, were examined. The determination of SARS-CoV-2 RNA was carried out weekly from December 2021 to January 2022 by taking smears from the oropharynx and examining them using a test-PCR systems manufactured by the Federal State Budgetary Institution of the Central Research Institute of Epidemiology of Rospotrebnadzor «AmplisensCov-Bat-FL» (registration certificate No. RZN 2014/1987 dated 07.04.2020). Results. SARS-CoV-2 RNA was detected in 41 (8.0% [95% CI 5.6÷10.4]) of 510 international students surveyed. Among those vaccinated with vector vaccines based on human adenovirus (Sputnik V, Sputnik Light, Ad26. COV2.S (Johnson&Johnson)) SARS-CoV-2 RNA was detected in 27 (7.6% [95% CI 4.8÷10.4]) a person, mainly after 4–6 months. after vaccination; vaccines based on modified mRNA (BNT162b2 (Pfizer/BioNTech), mRNA1273 (Moderna)) – 5.7% [95% CI 1.1÷10.3] people within six months after vaccination. The infectious process was asymptomatic in 39 people, in two (vaccinated with the BNT162b2 vaccine (Pfizer / BioNTech) and Sputnik Light) it had clinical manifestations of severe and moderate severity. Conclusion. Among foreign students vaccinated against COVID-19, in addition to two cases, asymptomatic carriers of SARS-CoV-2 have been identified, which may be a potential source of infection. This indicates the need for vaccination and timely revaccination of foreign and Russian students, as well as compliance with the anti-epidemic regime.

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Corynebacteria non-diphtheria and, in particular, C. pseudodiphtheriticum species that are closely related to C. propinquum and C. striatum form a group of new respiratory pathogens leading to the development of bronchitis, tracheitis, exacerbation of chronic obstructive pulmonary diseases, nosocomial pneumonia and other pathology. The goal is to analyze the frequency of the release of Сorynebacteria non-diphtheria from the upper respiratory tract of patients with various inflammatory diseases of the respiratory tract. Strains of Сorynebacteria non-diphtheria (C. pseudodiphtheriticum, C. propinquum, C. accolens, et al.), isolated from patients with inflammatory diseases of the respiratory tract (60 pcs.) and practically healthy individuals (31 pcs.) were studied. Identification of Сorynebacteria was performed using the method of mass spectrometry (MALDI-ToFMS). Сorynebacteria non-diphtheria in the amount of 105 and higher were more frequently detected with the development of chronic tonsillitis (60.0%) and nasopharyngitis (30%). The strains of C. pseudodiphtheriticum (40.0±6.4%) and the closely related species C. propinquum (21.7±5.3%) were mainly found; much less often - C. accolens (8.3±3.6%), C. afermentans (6.7±3.3%), et al. In 86.7% of cases, Corynebacteria non-diphtheria were isolated from children. In chronic tonsillitis, C. pseudodiphtheriticum and the closely related species of C. propinquum were isolated more often; in nasopharyngitis and bronchitis - С. pseudodiphtheriticum. Isolation of Corynebacteria non-diphtheria and, especially, C. pseudodiphtheriticum, C. propinquum, C. accolens species from patients with inflammatory diseases of the respiratory tract in the amount of 105 and above, if there are no other pathogenic microorganisms in the role of microbial associates, of clinical importance.