Analysis and Perception of Chlamydia psittaci Pneumonia: Novel Insights of the Rare Disease in Infectiology

Objective: To investigate and analyze the clinical features, diagnosis and treatment, and prognosis of rare Chlamydia psittaci pneumonia, and to improve the understanding of this rare disease. Methods: A retrospective analysis and exploration was performed for 33 cases of patients with Chlamydia psittaci pneumonia in the First Affiliated Hospital of Gannan Medical University from January 2017 to March 2024, and the clinical features, diagnosis, treatment and key points for differential diagnosis were summarized and analyzed. Meanwhile, the latest literature from PubMed was retrieved to systematically discuss the research progress in Chlamydia psittaci pneumonia. Results: A total of 33 patients with Chlamydia psittaci pneumonia were included in this study, including 21 males (63.64%) and 12 females (36.36%), with a median age of 59 (32-79) years. There were 27 cases (81.82%) of patients accompanied with a history of poultry contact, 22 patients (66.67%) had underlying diseases. In our study, patients with Chlamydia psittaci pneumonia were mainly affected in Autumn (21.21%) and Winter (54.55%). All patients had undergone bronchoscopy and obtained bronchoalverolar lavage fluid (BALF) for metagenomic next-generation sequencing (mNGS) detection, and mNGS results showed that all patients (100%) were co-infected with multiple pathogens including Chlamydia psittaci. All patients were given antimicrobial therapy after diagnosis, and no treatment-related adverse reactions or adverse events were observed in our study, the average length of hospitalization was 11.09 days. Fortunately, no death was observed in our study, and patients were all discharged from hospital after recovery and in favourable physical and psychological conditions after discharge. Conclusion: Chlamydia psittaci pneumonia lacks specific clinical features or manifestations and tends to develop into severe exacerbation. mNGS could help to achieve an accurate diagnosis. Early administration of antibiotics can improve the prognosis of patients to the greatest extent.