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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Problems of Virology</journal-id><journal-title-group><journal-title xml:lang="en">Problems of Virology</journal-title><trans-title-group xml:lang="ru"><trans-title>Вопросы вирусологии</trans-title></trans-title-group></journal-title-group><issn publication-format="print">0507-4088</issn><issn publication-format="electronic">2411-2097</issn><publisher><publisher-name xml:lang="en">Central Research Institute for Epidemiology</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">16845</article-id><article-id pub-id-type="doi">10.36233/0507-4088-363</article-id><article-id pub-id-type="edn">gxgumt</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>ORIGINAL RESEARCHES</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Efficacy of the interferon inducer tilorone and its combination with antibacterial drugs in a murine model of secondary bacterial pneumonia caused by <italic>S. aureus</italic> after influenza infection</article-title><trans-title-group xml:lang="ru"><trans-title>Эффективность индуктора интерферонов тилорона и его комбинации с антибактериальными препаратами на модели вторичной бактериальной пневмонии мышей, вызванной <italic>S. аureus</italic> после гриппозной инфекции</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-9836-9620</contrib-id><name-alternatives><name xml:lang="en"><surname>Falynskova</surname><given-names>Irina N.</given-names></name><name xml:lang="ru"><surname>Фалынскова</surname><given-names>Ирина Николаевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Researcher of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>falynskova@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-2004-3935</contrib-id><name-alternatives><name xml:lang="en"><surname>Poromov</surname><given-names>Artem A.</given-names></name><name xml:lang="ru"><surname>Поромов</surname><given-names>Артем Андреевич</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>PhD, Senior Researcher of Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>канд. биол. наук, старший научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>aap1309@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-8532-4690</contrib-id><name-alternatives><name xml:lang="en"><surname>Mikhailova</surname><given-names>Natalia A.</given-names></name><name xml:lang="ru"><surname>Михайлова</surname><given-names>Наталья Александровна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>D.Sci. (Med.), Head of the laboratory of protective antigens </p></bio><bio xml:lang="ru"><p>д-р мед. наук,<bold> </bold>заведующая лабораторией протективных антигенов<bold> </bold></p></bio><email>n_michailova@inbox.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-2096-5080</contrib-id><name-alternatives><name xml:lang="en"><surname>Kartashova</surname><given-names>Nadezhda P.</given-names></name><name xml:lang="ru"><surname>Карташова</surname><given-names>Надежда Павловна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Researcher of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>nadezdakartasova10571@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-5925-9733</contrib-id><name-alternatives><name xml:lang="en"><surname>Glubokova</surname><given-names>Ekaterina A.</given-names></name><name xml:lang="ru"><surname>Глубокова</surname><given-names>Екатерина Андреевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Researcher of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>prototype73.ake@yandex.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-7289-693X</contrib-id><name-alternatives><name xml:lang="en"><surname>Ivanina</surname><given-names>Anna V.</given-names></name><name xml:lang="ru"><surname>Иванина</surname><given-names>Анна Валерьевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Junior Researcher<bold> </bold>of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>младший научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>ivanina.anna97@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-9579-1102</contrib-id><name-alternatives><name xml:lang="en"><surname>Gudova</surname><given-names>Natalia V.</given-names></name><name xml:lang="ru"><surname>Гудова</surname><given-names>Наталия Владимировна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>PhD, Researcher of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>канд. биол. наук, научный сотрудник лаборатории экспериментальной вирусологии</p></bio><email>natalie83@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-7755-2714</contrib-id><name-alternatives><name xml:lang="en"><surname>Leneva</surname><given-names>Irina A.</given-names></name><name xml:lang="ru"><surname>Ленева</surname><given-names>Ирина Анатольевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>D.Sci. (Biol.), Head of the Laboratory of Experimental Virology </p></bio><bio xml:lang="ru"><p>д-р биол. наук, заведующая лабораторией </p></bio><email>wnyfd385@yandex.ru</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">Mechnikov Research Institute of Vaccines and Sera</institution></aff><aff><institution xml:lang="ru">ФГБНУ «Научно-исследовательский институт вакцин и сывороток им. И.И. Мечникова»</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2026-03-23" publication-format="electronic"><day>23</day><month>03</month><year>2026</year></pub-date><volume>71</volume><issue>1</issue><issue-title xml:lang="en"/><issue-title xml:lang="ru"/><fpage>73</fpage><lpage>82</lpage><history><date date-type="received" iso-8601-date="2025-12-19"><day>19</day><month>12</month><year>2025</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2026, Falynskova I.N., Poromov A.A., Mikhailova N.A., Kartashova N.P., Glubokova E.A., Ivanina A.V., Gudova N.V., Leneva I.A.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2026, Фалынскова И.Н., Поромов А.А., Михайлова Н.А., Карташова Н.П., Глубокова Е.А., Иванина А.В., Гудова Н.В., Ленева И.А.</copyright-statement><copyright-year>2026</copyright-year><copyright-holder xml:lang="en">Falynskova I.N., Poromov A.A., Mikhailova N.A., Kartashova N.P., Glubokova E.A., Ivanina A.V., Gudova N.V., Leneva I.A.</copyright-holder><copyright-holder xml:lang="ru">Фалынскова И.Н., Поромов А.А., Михайлова Н.А., Карташова Н.П., Глубокова Е.А., Иванина А.В., Гудова Н.В., Ленева И.А.</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://virusjour.crie.ru/jour/article/view/16845">https://virusjour.crie.ru/jour/article/view/16845</self-uri><abstract xml:lang="en"><p><bold>Introduction.</bold> Secondary bacterial pneumonias are complications responsible for most fatalities following influenza infection, and antiviral drugs are used to prevent their development.</p> <p><bold>The aim</bold> of the study is to evaluate the efficacy of tilorone and its combination with antibacterial agents in a murine model of secondary bacterial pneumonia caused by <italic>Staphylococcus aureus</italic> after influenza infection.</p> <p><bold>Materials and methods. </bold>BALB/c mice were infected with influenza virus A/California/04/2009 (pdm H1N1 2009) virus, followed by <italic>S.</italic> <italic>aureus</italic> infection four days later. Treatments included the interferon inducer tilorone, comparator oseltamivir, antibacterial agents cefuroxime and amoxicillin, or combinations of antivirals with antibiotics. Efficacy was assessed by increased survival, reduced weight loss, and inhibition of pathogen proliferation in the lungs.</p> <p><bold>Results.</bold><italic> </italic>The efficacy of tilorone, as indicated by increased survival, reduced weight loss, and decreased pathogen load in the lungs, in a mouse model of secondary bacterial pneumonia following influenza infection, increased with reducing viral dose, and intraperitoneal administration of the drug was more effective than oral administration. The combination of tilorone with the antibiotic cefuroxime, to which <italic>S. aureus</italic> was sensitive, was more effective than either agent alone and completely protected animals from death and from viral and bacterial proliferation in the lungs. In contrast, the combination with amoxicillin, to which <italic>S. aureus</italic> was resistant, had no effect on disease outcome.</p> <p><bold>Conclusion. </bold>The efficacy of tilorone in this model depended on viral dose and drug administration route. Combining tilorone with cefuroxime was more effective than monotherapy.</p></abstract><trans-abstract xml:lang="ru"><p><bold>Введение.</bold><italic> </italic>Вторичные бактериальные пневмонии – осложнения, вызывающие б'ольшую часть смертельных исходов после гриппозной инфекции, для предотвращения развития которых применяют противовирусные препараты.</p> <p><bold>Цель:</bold> изучение эффективности тилорона и его комбинации с антибактериальными препаратами на модели вторичной бактериальной пневмонии мышей после гриппозной инфекции, вызванной <italic>Staphylococcus</italic> <italic>aureus</italic>.</p> <p><bold>Материалы и методы.</bold> Мышей BALB/c инфицировали вирусом гриппа А/Калифорния/04/2009 (пндм H1N1 2009), а через 4 сут – <italic>S. aureus.</italic> Лечение проводили индуктором интерферона тилороном, препаратом сравнения осельтамивиром, антибактериальными препаратами цефуроксимом и амоксициллином или комбинациями противовирусных препаратов с антибиотиками. Эффективность лечения оценивали по увеличению выживаемости, снижению потери массы тела, предотвращению размножения вируса и бактерий в легких.</p> <p><bold>Результаты.</bold> Эффективность тилорона увеличивалась с уменьшением дозы вируса, а внутрибрюшинное введение было эффективнее перорального. Комбинация тилорона с антибиотиком цефуроксимом, к которому был чувствителен <italic>S. aureus</italic>, была эффективнее, чем применение каждого препарата отдельно, и полностью защищала животных от гибели и размножения вируса и бактерий в легких, а комбинация с амоксициллином, к которому <italic>S. aureus</italic> устойчив, не влияла на исход заболевания.</p> <p><bold>Заключение.</bold> Эффективность индуктора интерферонов тилорона на модели вторичной бактериальной пневмонии мышей после гриппозной инфекции зависела от заражающей дозы вируса и способа введения препарата. Применение комбинации тилорона с цефуроксимом показало более выраженную эффективность, чем каждого препарата отдельно.</p></trans-abstract><kwd-group xml:lang="en"><kwd>influenza virus</kwd><kwd>Staphylococcus aureus</kwd><kwd>secondary bacterial pneumonia following influenza infection</kwd><kwd>tiloron</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>вирус гриппа</kwd><kwd>Staphylococcus aureus</kwd><kwd>вторичные бактериальные пневмонии после гриппозной инфекции</kwd><kwd>тилорон</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>Lei B., Wang S., Yu L., Ma Q. Post-influenza bacterial infection: mechanisms of pathogenesis and advances in therapeutic strategies. Front. Microbiol. 2025; 16: 1673643. https://doi.org/10.3389/fmicb.2025.1673643</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>Potter C. W. Chronicle of influenza pandemics. In: Nicholson K.G., Webster R.G., Hay A.J., eds. 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