Clinical Characteristics of 40 Cases of Chlamydia Psittaci Pneumonia Confirmed by Metagenomic Next-Generation Sequencing.

Authors

Tangjuan Liu, Liexiang Liao, Xiaojing Zhang, Yafeng Zheng, Chongxi Bao, Yujing Qi, Lu Zhu, Yanbin Wu, Yi Liang

Published in

Infection and drug resistance. Volume 19. Pages 623888. Epub Aug 18, 2026.

Abstract

Chlamydia psittaci pneumonia is an underrecognized zoonotic infection with potentially severe outcomes, and its clinical features in the context of metagenomic next-generation sequencing (mNGS)-based diagnosis warrant systematic characterization. This study aimed to describe the clinical, laboratory, imaging, and bronchoscopic characteristics of mNGS-confirmed C. psittaci pneumonia and to explore features associated with severe community-acquired pneumonia (SCAP).
We conducted a single-center retrospective study analyzing clinical data from 40 patients with community-acquired pneumonia (CAP) caused by C. psittaci, diagnosed via mNGS at the First Affiliated Hospital of Guangxi Medical University from September 2019 to September 2024. General information, clinical symptoms, laboratory findings, imaging features, treatment, and prognosis were reviewed. Continuous variables were compared using Student's t-test or Mann-Whitney U-test as appropriate; categorical variables were compared using chi-square or Fisher's exact test.
All 40 patients had a clear history of poultry exposure. Among them, 13 cases (32.5%) were classified as severe CAP (SCAP), and 27 were non-SCAP. SCAP patients more frequently exhibited high fever, dyspnea, and extrapulmonary manifestations, with severe hypoxia. The most common chest CT findings were pulmonary consolidation, air bronchograms, and infiltrative shadows. Bronchoscopy revealed congestion and edema in 75% of patients, with SCAP cases having more abundant secretions. mNGS co-detection of other organisms was common, but the proportion of clinically confirmed co-infections was lower. SCAP patients showed significantly higher WBC, NEUT, CRP, PCT, Cr, and BUN levels and lower LYM and CD4⁺ counts (P < 0.05). All patients improved and were discharged after treatment with tetracyclines or quinolones, with no in-hospital mortality.
C. psittaci pneumonia should be suspected in CAP patients with poultry exposure, particularly when accompanied by declining oxygenation index or extrapulmonary manifestations such as headache. Pleural effusion on chest CT showed a trend toward higher frequency in SCAP patients (P=0.075), warranting further investigation. BALF mNGS may facilitate timely pathogen identification when conventional diagnostic methods are unavailable. Clinical improvement was observed following tetracycline- or quinolone-containing regimens. These findings are exploratory and require validation in larger prospective multicenter cohorts.

PMID:
42633455
Bibliographic data and abstract were imported from PubMed on 23 Aug 2026.

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