{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T05:12:24Z","timestamp":1790745144793,"version":"4.1.0"},"reference-count":43,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2019,12,17]],"date-time":"2019-12-17T00:00:00Z","timestamp":1576540800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"InfectoGnostics \u2018Innovative Diagnostik f\u00fcr Pneumonien bei Immunsuppression\u2019","award":["13GW0096D"],"award-info":[{"award-number":["13GW0096D"]}]},{"name":"Interdisciplinary Center of Clinical Research (IZKF) Jena University Hospital","award":["ACSP02"],"award-info":[{"award-number":["ACSP02"]}]},{"name":"German Federal Ministry of Education and Research grant","award":["(01KI07145)"],"award-info":[{"award-number":["(01KI07145)"]}]},{"name":"Federal Ministry of Education and Research KliFo 2.0","award":["(grant number 01KI1501)."],"award-info":[{"award-number":["(grant number 01KI1501)."]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Staphylococcus aureus is a facultative pathogenic bacterium that colonizes the nasopharyngeal area of healthy individuals, but can also induce severe infection, such as pneumonia. Pneumonia caused by mono- or superinfected S. aureus leads to high mortality rates. To establish an infection, S. aureus disposes of a wide variety of virulence factors, which can vary between clinical isolates. Our study aimed to characterize pneumonia isolates for their virulent capacity. For this, we analyzed isolates from colonization, pneumonia due to S. aureus, and pneumonia due to S. aureus\/influenza virus co-infection. A total of 70 strains were analyzed for their virulence genes and the host\u2013pathogen interaction was analyzed through functional assays in cell culture systems. Strains from pneumonia due to S. aureus mono-infection showed enhanced invasion and cytotoxicity against professional phagocytes than colonizing and co-infecting strains. This corresponded to the high presence of cytotoxic components in pneumonia strains. By contrast, strains obtained from co-infection did not exhibit these virulence characteristics and resembled strains from colonization, although they caused the highest mortality rate in patients. Taken together, our results underline the requirement of invasion and toxins to cause pneumonia due to S. aureus mono-infection, whereas in co-infection even low-virulent strains can severely aggravate pneumonia.<\/jats:p>","DOI":"10.3390\/toxins11120734","type":"journal-article","created":{"date-parts":[[2019,12,20]],"date-time":"2019-12-20T03:19:36Z","timestamp":1576811976000},"page":"734","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["Staphylococcus aureus Pneumonia: Preceding Influenza Infection Paves the Way for Low-Virulent Strains"],"prefix":"10.3390","volume":"11","author":[{"given":"Stefanie","family":"Deinhardt-Emmer","sequence":"first","affiliation":[{"name":"Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"},{"name":"Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Hans-Kn\u00f6ll-Str. 2, D-07745 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karoline Frieda","family":"Haupt","sequence":"additional","affiliation":[{"name":"Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Hans-Kn\u00f6ll-Str. 2, D-07745 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marina","family":"Garcia-Moreno","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jennifer","family":"Geraci","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christina","family":"Forstner","sequence":"additional","affiliation":[{"name":"Institute for Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"},{"name":"Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, A-1090 Vienna, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8157-2753","authenticated-orcid":false,"given":"Mathias","family":"Pletz","sequence":"additional","affiliation":[{"name":"Institute for Infectious Diseases and Infection Control, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"},{"name":"CAPNETZ Stiftung, D-30625 Hannover, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8879-6087","authenticated-orcid":false,"given":"Christina","family":"Ehrhardt","sequence":"additional","affiliation":[{"name":"Section of Experimental Virology, Institute of Medical Microbiology, Jena University Hospital, Hans-Kn\u00f6ll-Str. 2, D-07745 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bettina","family":"L\u00f6ffler","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Jena University Hospital, Am Klinikum 1, D-07747 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"309","DOI":"10.1016\/j.jhin.2017.12.011","article-title":"Virulence patterns of Staphylococcus aureus strains from nasopharyngeal colonization","volume":"100","author":"Sachse","year":"2018","journal-title":"J. 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