Mycobacterium abscessus is a rapidly growing nontuberculous mycobacteria (NTM) ubiquitous in the environment and can form mature colonies on solid media within seven days[1]. They were first isolated from subcutaneous abscesses in 1953[2] and classified as a subspecies of Mycobacterium chelonae until 1992[1], with extensive and intrinsic resistance to antimicrobial therapy[3]. M. abscessus infection is more common in skin and soft tissue in immunocompetent children[4,5]. Pulmonary infection usually occurs in pediatric patients with immune deficiency and chronic lung disease such as cystic fibrosis (CF) or other underlying lung pathology. The main lesions seen are the intratracheal lesions and hilar lymph node enlargement[6]. It rarely causes interstitial pulmonary parenchymal disease in immunocompetent infants; only two cases have been previously reported in English-language publications[7,8].

With the control of tuberculosis in China for decades, the prevalence of M. abscessus infections is increasing. While the NTM separation rate reaches 46.1 % in adults, no relevant data on children has been reported previously[9]. The diagnosis of M. abscessus pulmonary disease (MABC-PD) is complicated by the difficulty in differentiating the clinical features, radiographic characteristics, and conventional microbiological test results from those of other mycobacterial infections, easy to cause misdiagnosis and missed diagnosis[10]. Treatment of MABC-PD is extremely challenging for pediatricians with the lack of well-established antimicrobial treatment regimens and high rates of treatment failure and relapse.

We describe to our knowledge the first case of culture-confirmed M. abscessus interstitial pulmonary parenchymal disease in an otherwise healthy immunocompetent young infant. We also review the literature on MABC-PD in immunocompetent children to understand whether there are common clinical characteristics and treatment outcomes.