{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T13:44:04Z","timestamp":1793108644717,"version":"4.5.0"},"reference-count":30,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2023,12,13]],"date-time":"2023-12-13T00:00:00Z","timestamp":1702425600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Public Health"],"abstract":"<jats:sec><jats:title>Objectives<\/jats:title><jats:p>This study aimed to investigate the etiology, clinical features, and outcomes of community-acquired pneumonia (CAP) in adults. Understanding the causative pathogens is essential for effective treatment and prevention.<\/jats:p><\/jats:sec><jats:sec><jats:title>Design<\/jats:title><jats:p>Between 2016\u20132018, 518 hospitalized adults with CAP and 241 controls without symptoms were prospectively enrolled. Urine samples were collected for pneumococcal urinary antigen tests and nasopharyngeal swabs for viral and bacterial analysis, combined with routine diagnostic care.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Among the included CAP patients, <jats:italic>Streptococcus pneumoniae<\/jats:italic> was the most common pathogen, detected in 28% of patients, followed by <jats:italic>Haemophilus influenzae<\/jats:italic> in 16%. Viruses were identified in 28%, and concurrent viruses and bacteria were detected in 15%. There was no difference in mortality, length of stay, or symptoms at hospitalization when comparing patients with bacterial, viral, or mixed etiologies. Among the control subjects without respiratory symptoms, <jats:italic>S. pneumoniae<\/jats:italic>, <jats:italic>H. influenzae<\/jats:italic>, or <jats:italic>Moraxella catarrhalis<\/jats:italic> were detected in 5\u20137%, and viruses in 7%.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p><jats:italic>Streptococcus pneumoniae<\/jats:italic> emerged as the predominant cause of CAP, followed closely by viruses and <jats:italic>H. influenzae<\/jats:italic>. Intriguingly, symptoms and outcome were similar regardless of etiology. These findings highlight the complexity of this respiratory infection and emphasize the importance of comprehensive diagnostic and treatment strategies.<\/jats:p><jats:p><jats:bold>Clinical Trial Registration<\/jats:bold>: <jats:ext-link>ClinicalTrials.gov<\/jats:ext-link>, identifier [NCT03606135].<\/jats:p><\/jats:sec>","DOI":"10.3389\/fpubh.2023.1258981","type":"journal-article","created":{"date-parts":[[2023,12,13]],"date-time":"2023-12-13T20:40:16Z","timestamp":1702500016000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":22,"title":["Exploring the microbial landscape: uncovering the pathogens associated with community-acquired pneumonia in hospitalized patients"],"prefix":"10.3389","volume":"11","author":[{"given":"Karin","family":"Hansen","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linda","family":"Yamba Yamba","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Wasserstrom","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elisabeth","family":"R\u00fcnow","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tommy","family":"G\u00f6ransson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Nilsson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonas","family":"Ahl","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristian","family":"Riesbeck","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2023,12,13]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"1191","DOI":"10.1016\/S1473-3099(18)30310-4","article-title":"Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990\u20132016: a systematic analysis for the global burden of disease study 2016","volume":"18","author":"Troeger","year":"2018","journal-title":"Lancet Infect Dis"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"689","DOI":"10.1111\/joim.12956","article-title":"The changing epidemiology of community-acquired pneumonia: nationwide register-based study in Sweden","volume":"286","author":"Naucler","year":"2019","journal-title":"J Intern Med"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"340","DOI":"10.1136\/thx.2010.143982","article-title":"Microbial aetiology of community-acquired pneumonia and its relation to severity","volume":"66","author":"Cilloniz","year":"2011","journal-title":"Thorax"},{"key":"ref4","doi-asserted-by":"publisher","first-page":"e0001522","DOI":"10.1128\/cmr.00015-22","article-title":"The microbial etiology of community-acquired pneumonia in adults: from classical bacteriology to host transcriptional signatures","volume":"35","author":"Gadsby","year":"2022","journal-title":"Clin Microbiol Rev"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"e0037922","DOI":"10.1128\/spectrum.00379-22","article-title":"Utility of polymerase chain reaction in nasopharyngeal swabs for identifying respiratory Bacteria causing community-acquired pneumonia","volume":"10","author":"Demars","year":"2022","journal-title":"Microbiol Spectr"},{"key":"ref6","doi-asserted-by":"publisher","first-page":"817","DOI":"10.1093\/cid\/civ1214","article-title":"Comprehensive molecular testing for respiratory pathogens in community-acquired pneumonia","volume":"62","author":"Gadsby","year":"2016","journal-title":"Clin Infect Dis"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"629","DOI":"10.1016\/S0140-6736(22)02185-7","article-title":"Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis","volume":"399","author":"Murray","year":"2022","journal-title":"Lancet"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"1086648","DOI":"10.3389\/fpubh.2023.1086648","article-title":"Radiographically confirmed community-acquired pneumonia in hospitalized adults due to pneumococcal vaccine serotypes in Sweden, 2016\u20132018\u2014the ECAPS study","volume":"11","author":"Hansen","year":"2023","journal-title":"Front Public Health"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"243","DOI":"10.1056\/NEJM199701233360402","article-title":"A prediction rule to identify low-risk patients with community-acquired pneumonia","volume":"336","author":"Fine","year":"1997","journal-title":"N Engl J Med"},{"key":"ref10","doi-asserted-by":"publisher","first-page":"11","DOI":"10.1016\/j.jinf.2013.03.003","article-title":"Can an etiologic agent be identified in adults who are hospitalized for community-acquired pneumonia: results of a one year study","volume":"67","author":"Musher","year":"2013","journal-title":"J Infect"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1056\/NEJMoa1500245","article-title":"Community-acquired pneumonia requiring hospitalization among U.S. Adults","volume":"373","author":"Jain","year":"2015","journal-title":"N Engl J Med"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"64","DOI":"10.1186\/s12879-015-0803-5","article-title":"Etiology of community-acquired pneumonia and diagnostic yields of microbiological methods: a 3-year prospective study in Norway","volume":"15","author":"Holter","year":"2015","journal-title":"BMC Infect Dis"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"202","DOI":"10.1086\/648678","article-title":"Etiology of community-acquired pneumonia: increased microbiological yield with new diagnostic methods","volume":"50","author":"Johansson","year":"2010","journal-title":"Clin Infect Dis"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"ofy010","DOI":"10.1093\/ofid\/ofy010","article-title":"Incidence, etiology, and outcomes of community- acquired pneumonia: a population-based study","volume":"5","author":"Bjarnason","year":"2018","journal-title":"Open Forum Infect Dis"},{"key":"ref15","doi-asserted-by":"publisher","first-page":"1075","DOI":"10.1093\/cid\/ciab307","article-title":"The evolution and distribution of pneumococcal serotypes in adults hospitalized with community-acquired pneumonia in Spain using a serotype-specific urinary antigen detection test: the CAPA study, 2011\u20132018","volume":"73","author":"Torres","year":"2021","journal-title":"Clin Infect Dis"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"1216","DOI":"10.1093\/cid\/ciab375","article-title":"Expanded analysis of 20 pneumococcal serotypes associated with radiographically confirmed community-acquired pneumonia in hospitalized US adults","volume":"73","author":"Isturiz","year":"2021","journal-title":"Clin Infect Dis"},{"key":"ref17","volume-title":"Smoking","year":"2022"},{"key":"ref18","doi-asserted-by":"publisher","first-page":"1736","DOI":"10.15585\/mmwr.mm6946a4","article-title":"Tobacco product use among adults - United States, 2019","volume":"69","author":"Cornelius","year":"2020","journal-title":"MMWR Morb Mortal Wkly Rep"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"533","DOI":"10.1007\/s15010-021-01605-w","article-title":"Shift in bacterial etiology from the CAPNETZ cohort in patients with community-acquired pneumonia: data over more than a decade","volume":"49","author":"Braeken","year":"2021","journal-title":"Infection"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"122","DOI":"10.1080\/23744235.2020.1846776","article-title":"The increasing importance of HaemophilusInfluenzae in community-acquired pneumonia: results from a Danish cohort study","volume":"53","author":"Fally","year":"2021","journal-title":"Infect Dis (Lond)"},{"key":"ref21","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1099\/mgen.0.000209","article-title":"Pneumococcal vaccine impacts on the population genomics of non-typeable Haemophilus influenzae","volume":"4","author":"Cleary","year":"2018","journal-title":"Microb Genom"},{"key":"ref22","doi-asserted-by":"publisher","first-page":"209.e1-.e7","DOI":"10.1016\/j.cmi.2016.11.006","article-title":"The spread and clinical impact of ST14CC- PBP3 type IIb\/a, a clonal group of non-typeable Haemophilus influenzae with chromosomally mediated \u03b2-lactam resistance-a prospective observational study","volume":"23","author":"M\u00e5nsson","year":"2017","journal-title":"Clin Microbiol Infect"},{"key":"ref23","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1080\/23744235.2017.1399316","article-title":"Management of community-acquired pneumonia in immunocompetent adults: updated Swedish guidelines 2017","volume":"50","author":"Athlin","year":"2018","journal-title":"Infect Dis (Lond)"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"525","DOI":"10.1128\/JCM.44.2.525-528.2006","article-title":"Nasopharyngeal versus oropharyngeal sampling for isolation of potential respiratory pathogens in adults","volume":"44","author":"Lieberman","year":"2006","journal-title":"J Clin Microbiol"},{"key":"ref25","doi-asserted-by":"publisher","first-page":"543","DOI":"10.1016\/j.chest.2022.01.053","article-title":"Influenza testing and treatment among patients hospitalized with community-acquired pneumonia","volume":"162","author":"Deshpande","year":"2022","journal-title":"Chest"},{"key":"ref26","doi-asserted-by":"publisher","first-page":"62","DOI":"10.1093\/cid\/ciu237","article-title":"Lower respiratory tract virus findings in mechanically ventilated patients with severe community-acquired pneumonia","volume":"59","author":"Karhu","year":"2014","journal-title":"Clin Infect Dis"},{"key":"ref27","doi-asserted-by":"publisher","first-page":"441","DOI":"10.1099\/jmm.0.067108-0","article-title":"The value of signs and symptoms in differentiating between bacterial, viral and mixed a etiology in patients with community-acquired pneumonia","volume":"63","author":"Huijskens","year":"2014","journal-title":"J Med Microbiol"},{"key":"ref28","doi-asserted-by":"publisher","first-page":"609","DOI":"10.3109\/00365548.2011.570785","article-title":"Clinical impact of combined viral and bacterial infection in patients with community-acquired pneumonia","volume":"43","author":"Johansson","year":"2011","journal-title":"Scand J Infect Dis"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"1575","DOI":"10.1007\/s11739-022-02999-7","article-title":"Sex and gender differences in community-acquired pneumonia","volume":"17","author":"Corica","year":"2022","journal-title":"Intern Emerg Med"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"138.e1-.e7","DOI":"10.1016\/j.cmi.2021.05.049","article-title":"Improvement of pneumococcal pneumonia diagnosis using quantitative real-time PCR targeting lytA in adult patients: a prospective cohort study","volume":"28","author":"Boix-Palop","year":"2022","journal-title":"Clin Microbiol Infect"}],"container-title":["Frontiers in Public Health"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2023.1258981\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,12,13]],"date-time":"2023-12-13T20:40:18Z","timestamp":1702500018000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpubh.2023.1258981\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,13]]},"references-count":30,"alternative-id":["10.3389\/fpubh.2023.1258981"],"URL":"https:\/\/doi.org\/10.3389\/fpubh.2023.1258981","relation":{},"ISSN":["2296-2565"],"issn-type":[{"value":"2296-2565","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,13]]},"article-number":"1258981"}}