Clinical characteristics and outcomes of Chlamydia psittaci pneumonia: Insights from targeted next-generation sequencing diagnosis

ObjectiveThe aim is to enhance clinician awareness of the disease, reduce the risk of misdiagnosis, and analyze the risk factors for the progression of Chlamydia psittaci infection to severe pneumonia.MethodsWe conducted a retrospective analysis of the clinical data from patients infected with Chlamydia psittaci at our hospital.ResultsThirty-three patients diagnosed with Chlamydia psittaci pneumonia were included in this study. Among them, 23 (72.2%) were male and 10 (27.8%) were female, with a mean age of 59.1 ± 11.1 years. Twenty-four patients (72.7%) had a clear history of poultry exposure. The main clinical manifestations were high fever (n = 30, 90.9%), cough (n = 28, 84.8%), chill (n = 24, 72.7%), expectoration (n = 22, 66.7%), fatigue (n = 20, 60.6%), poor appetite (n = 20, 60.6%), dyspnea (n = 13, 39.4%), and myalgia (n = 10, 30.3%). The lymphocyte count in severe pneumonia group was significantly lower than that in non-severe pneumonia group. C-reactive protein, erythrocyte sedimentation rate, and lactate dehydrogenase levels in the severe group were remarkably higher than those in the non-severe group. The common imaging findings included flake high-density shadows (n = 29, 87.9%), consolidation (n = 20, 60.6%), pleural effusion (n = 17, 51.5%), bronchial inflation signs (n = 15, 45.5%), and ground-glass exudation (n = 20, 60.6%). The majority of patients received treatment with either doxycycline alone, quinolones alone, or a combination of doxycycline and quinolones.ConclusionHistory of contact with birds or poultry, repeated high fever, and flake high-density shadows with consolidation in Chest computed tomography can serve as important indicators for diagnosing C. psittaci pneumonia. Lower lymphocyte counts were identified as the sole risk factor associated with severe C. psittaci pneumonia. Quinolones and doxycycline are effective treatments for C. psittaci pneumonia.