Two Cases of Severe Chlamydia psittaci Pneumonia with Respiratory Failure and Literature Review

BACKGROUND: Chlamydia psittaci pneumonia is a zoonotic disease with non-specific clinical manifestations, often leading to delayed diagnosis. Metagenomic next-generation sequencing (mNGS) can help us identify pathogens in a timely manner and quickly adjust treatment strategies. METHODS: We reported two cases of severe Chlamydia psittaci pneumonia with respiratory failure and reviewed relevant literature. RESULTS: Both patients were diagnosed with Chlamydia psittaci infection through mNGS after routine pathogen testing failed. After using Omadacycline based treatment, the patients' clinical and radiological characteristics improved significantly and were successfully cured. CONCLUSIONS: For patients infected with Chlamydia psittaci pneumonia, timely identification of the pathogen is crucial. mNGS can quickly detect Chlamydia psittaci in critically ill patients, guide clinical timely targeted treatment, and improve patient symptoms.