{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T17:51:36Z","timestamp":1779904296575,"version":"3.53.1"},"reference-count":39,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T00:00:00Z","timestamp":1753056000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Natural Science Foundation of YangZhou","award":["YZ2024187"],"award-info":[{"award-number":["YZ2024187"]}]},{"name":"Natural Science Foundation of YangZhou","award":["YZYXZDXK-010"],"award-info":[{"award-number":["YZYXZDXK-010"]}]},{"name":"Yangzhou Key Discipline Cultivation Program (Respiratory Disease)","award":["YZ2024187"],"award-info":[{"award-number":["YZ2024187"]}]},{"name":"Yangzhou Key Discipline Cultivation Program (Respiratory Disease)","award":["YZYXZDXK-010"],"award-info":[{"award-number":["YZYXZDXK-010"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Secondary methicillin-resistant Staphylococcus aureus (MRSA) infection causes high mortality in patients with influenza A virus (IAV). Our previous study observed that the relative abundance of Lactobacillus murinus (L. murinus) was significantly reduced in both the respiratory tract and gut of IAV-infected mice and negatively correlated with the severity of IAV\u2013MRSA coinfection pneumonia, but the role of L. murinus remains unclear. Here, we supplemented the respiratory tract and gut of IAV-infected mice with live L. murinus and performed a secondary MRSA infection challenge to investigate the effects and potential mechanisms further. Data showed that L. murinus supplementation significantly reduced mortality and pathogen loads in IAV\u2013MRSA coinfected mice and upregulated the lung T cell-independent (TI) IgA response in IAV-infected mice. The 16S rRNA gene sequencing results showed that L. murinus supplementation ameliorated microbiota composition disorder and regulated metabolic dysfunction in the gut of IAV-infected mice. The correlation analysis and antibiotic cocktail treatment experiment showed that the TI IgA response in lungs is dependent on gut microbiota. These findings demonstrated that L. murinus supplementation reduces susceptibility to secondary MRSA infection in IAV-infected mice by promoting the TI IgA response, and provide a new perspective on the use of probiotics to prevent secondary bacterial infection following IAV infection.<\/jats:p>","DOI":"10.3390\/microorganisms13071709","type":"journal-article","created":{"date-parts":[[2025,7,21]],"date-time":"2025-07-21T13:59:11Z","timestamp":1753106351000},"page":"1709","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Lactobacillus murinus Reduces Susceptibility to Secondary MRSA Infection in IAV-Infected Mice Through Promoting a T Cell-Independent IgA Response"],"prefix":"10.3390","volume":"13","author":[{"given":"Qichao","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Pulmonary and Critical Care Medicine, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou 225000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanfeng","family":"Lin","sequence":"additional","affiliation":[{"name":"Chinese PLA Center for Disease Control and Prevention, Beijing 100071, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kaiying","family":"Wang","sequence":"additional","affiliation":[{"name":"Chinese PLA Center for Disease Control and Prevention, Beijing 100071, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinhui","family":"Li","sequence":"additional","affiliation":[{"name":"Chinese PLA Center for Disease Control and Prevention, Beijing 100071, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peng","family":"Li","sequence":"additional","affiliation":[{"name":"Chinese PLA Center for Disease Control and Prevention, Beijing 100071, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongbin","family":"Song","sequence":"additional","affiliation":[{"name":"Chinese PLA Center for Disease Control and Prevention, Beijing 100071, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1016\/j.molmed.2020.09.014","article-title":"Influenza A Viruses: Understanding Human Host Determinants","volume":"27","author":"Ciminski","year":"2021","journal-title":"Trends Mol. 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