Yong Yang,1 Cheng Li,2 Xianshuang Fan,3 Wenming Long,4 Yuwei Hu,5 Yiming Wang,6 Jian Qu6,7 

1Department of Pharmacy, Affiliated Changsha Hospital of Hunan Normal University, Changsha, 410200, People’s Republic of China; 2Intensive Care Unit, Affiliated Changsha Hospital of Hunan Normal University, Changsha, 410200, People’s Republic of China; 3Department of General Medicine, the Fourth Hospital of Changsha, Changsha, 410200, People’s Republic of China; 4Department of Pharmacy, The Second People’s Hospital of Huaihua City (The Central Hospital of Huaihua City), Huaihua, 418400, People’s Republic of China; 5Department of Pharmacy, Longshan County People’s Hospital, Xiangxi Autonomous Prefecture, 416800, People’s Republic of China; 6Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, 410011, People’s Republic of China; 7Hunan Key Laboratory of the Research and Development of Novel Pharmaceutical Preparations, Changsha Medical University, Changsha, 410219, People’s Republic of China

Correspondence: Jian Qu, Hunan Key Laboratory of the Research and Development of Novel Pharmaceutical Preparations, Changsha Medical University, 1501 Leifeng Avenue, Xiangjiang New Area, Changsha, 410219, People’s Republic of China, Tel +86-15973190614, Fax +86-0731-85292128, Email qujianstanley@csu.edu.cn

Abstract: Chlamydia psittaci is one of the primary pathogens responsible for community-acquired atypical pneumonia. If not treated promptly, it can progress to severe pneumonia and may lead to multiple organ dysfunction as well as secondary infections with multi-drug-resistant (MDR) bacteria. Omadacycline, a novel aminomethylcycline antibiotic derived from tetracycline, exhibits high activity against various bacterial strains. This case report describes a patient who developed severe pneumonia caused by Chlamydia psittaci in conjunction with a MDR bacterial infection. Despite initial treatment with moxifloxacin and doxycycline, the patient experienced treatment failure. The patient’s condition deteriorated, presenting complications such as progressive infection, leukopenia, liver dysfunction, electrolyte imbalances, and respiratory alkalosis. Following the adjustment to omadacycline therapy for 48 hours, all complications were rapidly alleviated, leading to successful treatment of the patient.

Keywords: omadacycline, Chlamydia psittaci, multiple drug resistance, Kleber pneumoniae, Acinetobacter baumannii