Pneumonia Caused by Chlamydia psittaci and SARS-CoV-2 Coinfection Diagnosed Using Metagenomic Next-Generation Sequencing: A Case Report

Anbing Zhang,1,* Jinguang Liang,2,* Xiaoli Lao,1,3 Xiuqiong Xia,1 Jianping Liang1,3 1Department of Respiratory and Critical Care Medicine, Zhongshan People’s Hospital, Zhongshan, Guangdong Province, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, Zhongshan Huangpu People’s Hospital, Zhongshan, Guangdong Province, People’s Republic of China; 3Graduate School, Guangdong Medical University, Zhanjiang, Guangdong Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jianping Liang, Department of Respiratory and Critical Care Medicine, Zhongshan People’s Hospital, 2 Sunwen East Road, Zhongshan, 528400, People’s Republic of China, Tel +86-159-8910-7884, Fax +86-760-8988-0256, Email ljpzhongshan@163.comAbstract: We report a case of pneumonia caused by coinfection with Chlamydia psittaci and the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB.1 variant, confirmed using metagenomic next-generation sequencing (mNGS) and quantitative polymerase chain reaction (qPCR). C. psittaci and SARS-CoV-2 were detected in bronchoalveolar lavage fluid using mNGS. Additionally, mNGS detected C. psittaci in blood and nasopharyngeal specimens and was more sensitive than qPCR. The patient recovered after treatment with moxifloxacin. This report highlights the use of coinfections of C. psittaci and SARS-CoV-2, as mNGS has already been recognized to be a diagnostic tool for identifying coinfections.Keywords: coinfection, quantitative reverse-transcription polymerase chain reaction, bronchoalveolar lavage fluid, zoonoses