ORIGINAL RESEARCH article
Front. Med.
Sec. Pulmonary Medicine
Volume 12 - 2025 | doi: 10.3389/fmed.2025.1591963
A case-control study on Chlamydia psittaci pneumonia and Legionella pneumonia
Provisionally accepted
- The Wuxi Second People's Hospital, Wuxi, China
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Purpose: Atypical pathogens (Chlamydia psittaci and Legionella) are often detected by mNGS. However, the two atypical pneumonias are difficult to distinguish. The aim of this study was to retrospectively analyse the two types of atypical pneumonia and use statistics to find points of differentiation for early diagnosis and timely treatment. Methods: This retrospective study included all confirmed cases of two types of atypical pneumonia in our institution. The data collected and analyzed included epidemiological, clinical, laboratory, and radiological features. Results: The study included 84 patients, 63 with Chlamydia psittaci (C. psittaci) pneumonia, 21 with Legionella pneumonia. (1) Up to 61.9% of patients with C. psittaci pneumonia and Legionella pneumonia had high fevers. More than 90% of patients with Legionella pneumonia had a cough score ≥ 3. Legionella pneumonia patients experienced more severe coughing, chest tightness and wheezing symptoms than C. psittaci pneumonia patients (both, p < 0.01). (2) Consolidation, bronchial insufflation, ground-glass opacities, and pleural effusion are the most common chest CT signs of C. psittaci pneumonia and Legionella pneumonia. Legionella pneumonia was more likely to cause ground-glass opacities in the upper left lobe than C. psittaci pneumonia (p = 0.05). There was no statistical difference in other CT findings. (3) C. psittaci pneumonia and Legionella pneumonia were identified by leukocytes, lymphocytes ratio, NLR, blood glucose, cough, chest tightness and wheezing. They had AUC's of 0.810, 0.709, 0.728, 0.724, 0.795, 0.675, and all P < 0.05. (4) 69.8%, 80.9% of all patients took two or more antibiotics simultaneously before diagnosis, but p = 0.32. Some patients received more than four antibiotics, most commonly Legionella pneumonia (23.8%) (p = 0.01). Clinicians should consider C. psittaci and Legionella pneumonia, when patients present with high fever and chest CT scans showing consolidation accompanied by bronchial insufflation, ground-glass opacities, and pleural effusion. Initially, clinicians can differentiate between the two types of pneumonia based on symptoms, imaging features, and laboratory markers. This allows for the optimization of antibiotic choices and the reduction of unnecessary multidrug combinations, which can improve prognosis and reduce the risk of drug resistance.
Keywords: Chlamydia psittaci pneumonia, Legionella pneumonia, LASSO regression, retrospective analysis, Clinical Characteristics
Received: 11 Mar 2025; Accepted: 26 May 2025.
Copyright: © 2025 Gao, Lin, Zhang, Ni, Han and Bao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Ying Gao, The Wuxi Second People's Hospital, Wuxi, China
Liang Bao, The Wuxi Second People's Hospital, Wuxi, China
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