Clinical characteristics and misdiagnosis analysis of community-acquired Legionella pneumophila pneumonia

JIA Weihong; CHENG Yanyan; WANG Lina; HAO Nana; PU Lina; LIU Zhiyan; LIN Min

doi:10.3969/j.issn.1002-3429.2025.18.004

Abstract：Objective To explore the clinical characteristics and causes of missed diagnosis of community-acquired Legionella pneumophila pneumonia.Methods A retrospective analysis was conducted on the clinical data of 18 patients with community-acquired Legionella pneumophila pneumonia diagnosed by metagenomic next-generation sequencing(mNGS)of alveolar lavage fluid from January 2019 to May 2024.Results Among the 18 patients,18 had high fever,16 had cough,11 had expectoration,6 had fatigue,2 had chest tightness,2 had joint pain,and 2 had blood in the sputum.After relevant laboratory tests and chest CT examinations,it was misdiagnosed as common bacterial pneumonia.After corresponding treatment,the symptoms did not improve significantly.The diagnosis was Legionella pneumophila infection through mNGS examination of bronchoalveolar lavage fluid.The misdiagnosis lasted 5 to 14 d.After diagnosis,11 patients were treated with Moxifloxacin monotherapy,5 patients with Omacycline monotherapy,1 patient with Doxycycline monotherapy,and 1 patient with Piperacillin-Tazobactam combined with Omacycline.The treatment duration was 10 to 17 d.The clinical symptoms of all 18 patients were relieved and the chest imaging improved.All patients were cured at 3-month follow-up.Conclusion The clinical manifestations and chest imaging changes of Legionella pneumophila pneumonia are not specific,and its etiological diagnosis is relatively difficult.For suspected cases in clinical practice,mNGS detection of bronchoalveolar lavage fluid should be actively performed to clarify the etiological diagnosis,and effective and timely treatment should be given to improve the prognosis of patients.