Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Aug 16;25(1):1027.
doi: 10.1186/s12879-025-11450-z.

Clinical characteristics of Chlamydia psittaci pneumonia: a single-center, retrospective study over 5 years

Chunyan Zhu #  1 , Tingting Ye #  1 , Chongyang Ye #  1 , Mingyan Xu  1 , Yuxi He  1 , Dan Wang  1 , Xianling Meng  1 , Xiaoqing Fan  1 , Min Zhou  2   3
Affiliations

Clinical characteristics of Chlamydia psittaci pneumonia: a single-center, retrospective study over 5 years

Chunyan Zhu et al. BMC Infect Dis. .

Abstract

Background: Psittacosis pneumonia is not uncommon, and it can progress to severe illness or even death. Identifying the clinical characteristics of Chlamydia psittaci (C. psittaci ) pneumonia and its risk factors were the aim of improving decision-making regarding diagnosis and treatment.

Methods: According to the guidelines for CAP, 59 patients with C. psittaci pneumonia were divided into a non-severe pneumonia group and a severe pneumonia group, and their clinical characteristics and the differences were analyzed and compared.

Results: The incidence of consciousness disorders is higher(P = 0.020), and the time from onset to diagnosis is longer (8 days vs. 14 days, P = 0.002), it is more prone to myocardial injury, kidney injury, hypoalbuminemia, coagulation abnormalities, and venous thrombosis (P < 0.05) in the severe group, while fatigue is more common in the non-severe group (P = 0.022). On laboratory indicators, the severe pneumonia group had a significantly longer prothrombin time (P = 0.007), higher WBC and neutrophil percentages and lower lymphocyte count and percentages, higher lactate dehydrogenase and D-dimer values (all P < 0.001). After adjustment for sex and age, logistic regression analysis identified myocardial injury as an independent risk factor for severe C. psittaci pneumonia (OR, 124.3, [95%CI, 4.25 ~ 3633.24]; P = 0.005).

Conclusions: Impaired consciousness indicates severe illness and myocardial injury is an independent risk factor for severe C. psittaci pneumonia.

Keywords: Chlamydia psittaci; Community-acquired; Outcome; Pneumonia; Risk.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: This study was conducted in accordance with the ethical principles of the Declaration of Helsinki. Its was approved by the Ethics Committee of the First Affiliated Hospital of University of Science and Technology of China (No.2025-RE-097) and all methods were carried out in accordance with relevant guidelines and regulations. Confidentiality of the information related to study participates was assured during and after the data collection, and informed consent was waived by Ethics committee of the First Affiliated Hospital of University of Science and Technology of China because of its retrospective characterization. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests. Clinical trial number: Not applicable.

Figures

Fig. 1
Fig. 1
Flowchart showing the procedure used to select patients for inclusion in the study. CT, computed tomography; mNGS, metagenomic next-generation sequencing
Fig. 2
Fig. 2
Representative images of mild and severe pneumonia caused by Chlamydia psittaci. (A) Non-severe C. psittaci pneumonia showing patchy increased density in the left lower lung. (B) Non-severe C. psittaci pneumonia showing patchy increased density in the left lower lung and multiple ground-glass opacities and pleural effusion in both lungs. (C) Severe C. psittaci pneumonia showing extensive consolidation and ground-glass opacities in both lungs, predominantly in the right lung, with a small amount of pleural effusion. (D) Severe C. psittaci pneumonia showing an extensive increase in density in the right lung, predominantly consolidation.
Fig. 3
Fig. 3
Distribution of pathogens in C. psittaci pneumonia with co-infection.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Hogerwerf L, De Gier B, Baan B, et al. Chlamydia psittaci (psittacosis) as a cause of community-acquired pneumonia: a systematic review and meta-analysis. Epidemiol Infect. 2017;145(15):3096–105. 10.1017/S0950268817002060. - PMC - PubMed
    1. Chiu CY, Coffey LL, Murkey J, et al. Diagnosis of fatal human case of st. Louis encephalitis virus infection by metagenomic sequencing, California. Emerg Infect Dis. 2017;23(10):1964–8. 10.3201/eid2310.161986. - PMC - PubMed
    1. Xie Y, Du J, Jin W, et al. Next generation sequencing for diagnosis of severe pneumonia: China, 2010–2018. J Infect. 2019;78(2):158–69. 10.1016/j.jinf.2018.09.004. - PubMed
    1. Qu J, Zhang J, Chen Y, et al. Aetiology of severe community acquired pneumonia in adults identified by combined detection methods: a multi-centre prospective study in China. Emerg Microbes Infect. 2022;11(1):556–66. 10.1080/22221751.2022.2035194. - PMC - PubMed
    1. Mandell LA, Wunderink RG, Anzueto A et al. (2007). Infectious diseases society of America/American thoracic society consensus guidelines on the management of community acquired pneumonia in adults. Clin. Infect. Dis. 2007;44 (Suppl 2), S27–S72. 10.1086/511159 - PMC - PubMed

LinkOut - more resources