Evidence Hub

Diagnosis and management of mixed Chlamydia abortus and psittaci pneumonia guided by metagenomic next-generation sequencing: a case report

Liu L, Su P, Gong F, Wang A, Wang X, Yang L, Mo W, Jiang T

BMC infectious diseases, 2026

Abstract

Background: Chlamydia abortus primarily causes abortion and stillbirth in animals and is associated with pregnancy-related complications in humans. However, it is an extremely rare cause of pneumonia in humans. While Chlamydia psittaci is a well-established respiratory pathogen, pneumonia resulting from a co-infection with both species has not been previously reported.

Case presentation: A 57-year-old male presented with fever, cough, and shortness of breath. Imaging revealed extensive pulmonary inflammation and consolidation, which rapidly progressed to respiratory failure. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) confirmed a mixed infection with Chlamydia abortus and Chlamydia psittaci. Following the early initiation of targeted doxycycline therapy, the patient's clinical symptoms and pulmonary imaging showed significant improvement, leading to a full recovery and hospital discharge.

Conclusions: To our knowledge, this study reports the first case of atypical pneumonia caused by a mixed Chlamydia abortus and Chlamydia psittaci infection in a male patient, thereby expanding the clinical spectrum of these zoonotic pathogens. The case exhibited a "clinical-imaging dissociation," characterized by severe radiographic changes alongside relatively mild clinical symptoms. When conventional diagnostic methods failed to identify the pathogens, mNGS provided a rapid and precise diagnosis. Guided by this result, early targeted therapy with…

How strong is the evidence?

Evidence Hub reads this as a case report, done in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free