Jiahuan Tong,1,* Linshui Zhou,1,* Yan Chen,2 Liqun Xu,3 Jianfeng Wang1 

1Department of Respiratory Diseases, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou, People’s Republic of China; 2Department of General Practice, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou, People’s Republic of China; 3Department of Emergency Department, Affiliated Hospital of Hangzhou Normal University, Hangzhou, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Jianfeng Wang, Email 2001m@163.com

Abstract: 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.

Keywords: chlamydia pneumoniae, atypical pneumonia, bronchoalveolar lavage, next-generation sequencing, omadacycline