AUTHOR=Chen Yingying , Liang Sicong , Lu Ye , Zhou Xiangyu , Zheng Rui , Chen Yu 

TITLE=Case Report: First report of Legionella micdadei pneumonia and organizing pneumonia in a patient with myelodysplastic and Sweet syndromes

JOURNAL=Frontiers in Immunology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1510948

DOI=10.3389/fimmu.2025.1510948

ISSN=1664-3224

ABSTRACT=The immunocompromised population is susceptible to Legionella pneumonia. The diagnosis and treatment of Legionella pneumonia in immunocompromised individuals are challenging clinical endeavors. Previous studies have identified Legionella pneumonia as a potential cause of organizing pneumonia (OP), however, the association between Legionella pneumonia and OP has not received enough clinical attention. We retrospectively evaluated a case involving Legionella micdadei infection and OP in a patient with myelodysplastic syndrome and concurrent Sweet syndrome. The diagnosis of Legionella micdadei pneumonia was confirmed through various methods: metagenomic next generation sequencing (mNGS), Giemsa-staining and fluorescence in situ hybridization of lung tissue, as well as serum immunofluorescence antibody testing. Histopathological analysis of lung tissue revealed OP. The patient was successfully treated with a combination of antibiotics and low-dose glucocorticoids. In immunocompromised individuals, mNGS was capable of detection non-Legionella pneumophila serogroup 1. The pathological examination is important for identifying secondary OP and provides the evidence for treatment with glucocorticoids.