A Case of Secondary Pulmonary Syphilis – The Utility of mNGS in Bronchoalveolar Lavage Fluid: A Case Report

Xue Yang,1 Weigang Wu,2 Yongjie Wang,1 Wen Wu,1 Xia Huang,1 Li Xu3 1Shenzhen Institute of Respiratory Diseases, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, Guangdong, People’s Republic of China; 2Department of Infectious Disease, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, Guangdong, People’s Republic of China; 3Department of Respiratory and Critical Care Medicine, The First People’s Hospital of Chongqing Liangjiang New Area, Chongqing, People’s Republic of ChinaCorrespondence: Li Xu, Department of Respiratory and Critical Care Medicine, The First People’s Hospital of Chongqing Liangjiang New Area, Chongqing, People’s Republic of China, Email 419176498@qq.comAbstract: Syphilis is a sexually transmitted infectious disease caused by Treponema pallidum. Here, we report a rare case of secondary pulmonary syphilis, which was diagnosed by metagenomic next-generation sequencing (mNGS) in bronchoalveolar lavage fluid (BALF). Direct pulmonary involvement by T. pallidum was suggested by a positive mNGS result in BALF. One month after treatment with benzathine penicillin G (2.4 million units, three doses), a repeated CT scan showed the radiological resolution. To our knowledge, this is the first reported case of secondary pulmonary syphilis diagnosed by mNGS in BALF.Keywords: pulmonary, secondary syphilis, Treponema pallidum, mNGS