An Atypical Pneumonia Case of Quinolone-Refractory Chlamydia Pneumoniae Successfully Treated With Omadacycline.

Atypical pneumonia caused by Chlamydia pneumoniae often presents diagnostic challenges due to its nonspecific symptoms and slow progression. While most cases are mild and self-limiting, severe infections in immunocompetent adults are rare. This report describes a 32-year-old Chinese female with progressive pneumonia unresponsive to empirical quinolone therapy. Bronchoalveolar lavage (BAL) and next-generation sequencing (NGS) identified C. pneumoniae as the causative pathogen. The patient showed significant clinical improvement following treatment with omadacycline, a novel tetracycline-class antibiotic. This case highlights the importance of bronchoscopic evaluation, BAL cytology, and NGS in diagnosing atypical pneumonia. It also underscores omadacycline's potential in treating quinolone-refractory C. pneumoniae pneumonia.