Severe pneumonia caused by Chlamydia psittaci and Aspergillus terreus: a case report.

Chlamydia psittaci is a known cause of severe pneumonia and may be associated with invasive fungal co-infections; however, its complication by Aspergillus terreus is exceptionally rare. We report a case of a previously healthy 58-year-old woman with poultry exposure who presented with fever and dyspnea that rapidly progressed to respiratory failure requiring mechanical ventilation. After initial empirical antibiotics failed, targeted next-generation sequencing (tNGS) of bronchoalveolar lavage fluid concurrently identified Chlamydia psittaci and Aspergillus terreus, guiding successful targeted therapy with doxycycline and voriconazole, which led to full recovery. This case highlights the utility of tNGS in enabling rapid, simultaneous pathogen identification and guiding targeted therapy in severe pneumonia.