L. pneumophila Infection Diagnosed by tNGS in a Lady with Lymphadenopathy

Shiying Li,1 Jin Tong,2 Hu Li,1 Chenxue Mao,3 Wei Shen,1 Yu Lei,1 Peng Hu1 1Department of Infectious Diseases, Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, People’s Republic of China; 2Department of Respiratory Medicine, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, People’s Republic of China; 3Department of Laboratory Diagnosis, ChongQing KingMed Center for Clinical Laboratory Co., Ltd, Chongqing, 400050, People’s Republic of ChinaCorrespondence: Peng Hu, Department of Infectious Diseases, Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, The Second Affiliated Hospital, Chongqing Medical University, 74# Linjiang Road, Chongqing, 400010, People’s Republic of China, Email hp_cq@163.com; hupengcq@hospital.cqmu.edu.cnAbstract: We report a case of a 34-year-old lady with multiple joint pain. Autoimmune diseases were considered first with a positive result of anti-Ro antibody and her right knee joint cavity effusion. Later, bilateral interstitial changes in her lungs and mediastinal lymphadenopathy were found after chest CT scanning. Empirical quinolone therapy was given although pathological examinations of blood, sputum and bronchoalveolar lavage fluid (BALF) did not find anything. Finally, Legionella pneumophila was identified by target next-generation sequencing (tNGS) detection. This case highlighted the timely use of tNGS, a new tool with fast speed, high accuracy and effective cost, could help to identify atypical infection and start an early therapy.Keywords: case report, Legionella pneumophila, targeted next-generation sequencing, tNGS, precision treatment, levofloxacin