Successful management of Mycobacterium abscessus complex lung disease in an otherwise healthy infant Hui Liu,1 Fang Dong,2 Jinrong Liu,1 Jianhua Liu,3 Yu Pang,4 Shunying Zhao,1 Jie Lu,5 Huimin Li11Department of Respiratory Medicine, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, People’s Republic of China; 2Department of Laboratory Medicine, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, People’s Republic of China; 3Department of Pediatrics, Maternal and Child Health Care Hospital of Shunyi District, Beijing, People’s Republic of China; 4Beijing Chest Hospital, Capital Medical University, Beijing, People’s Republic of China; 5Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, Beijing, People’s Republic of ChinaAbstract: Mycobacterium abscessus complex (MABC) is an uncommon but increasingly important cause of invasive pulmonary disease, a condition associated with diagnostic and management challenges. MABC has mainly been reported in children with certain medical conditions, such as preexisting structural lung disorders and immunocompromised status. In this article, we describe a rare case of MABC pulmonary disease in an otherwise healthy infant. A 4-month-old female presented with cough and fever for 4 days. Computed tomography showed multiple masses and small nodules across both lungs. Isolated mycobacteria from her bronchoalveolar lavage fluid and gastric aspirate were identified as MABC by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and M. abscessus subsp. massiliense was ultimately identified by DNA sequence analysis. Prolonged treatment with a combination of azithromycin, cefoxitin, and moxifloxacin achieved a successful treatment outcome.Keywords: nontuberculous mycobacteria, pulmonary, drug resistance, azithromycin, treatment outcome