A case-control study on Chlamydia psittaci pneumonia and legionella pneumonia

Clinicians should consider atypical pneumonia, particularly <i>C. psittaci</i> and <i>Legionella</i> 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 (e.g., cough severity, chest tightness and shortness of breath), imaging features (e.g., GGO in the left upper lobe), and laboratory markers (e.g., glucose, leukocytes, NLR, and lymphopenia). 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.