Nontuberculous mycobacterial bloodstream infections after allogeneic hematopoietic stem cell transplantation

Non-tuberculous mycobacteria (NTM) bacteremia following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is rare, and limited data exist. We described the features of NTM bacteremia following allo-HSCT recipients in our hospital with a comprehensive review of the literature. Among the four cases of NTM bacteremia after allo-HSCT recipients in our hospital, two were catheter-related bloodstream infections (CRBSI), one was disseminated, and one was an unknown source of infection. Based on our report and the past literature, the incidence rate of NTM bacteremia was 0.1-1.3%. CRBSI (57%) was more common than disseminated infection (29%). Most cases with CRBSI were caused by rapidly growing mycobacteria (88%) and showed good prognoses under appropriate antimicrobial therapies. In contrast, slowly growing mycobacteria (71%) was more common than rapidly growing mycobacteria in disseminated NTM bacteremia. Although disseminated NTM bacteremia can remain stable with appropriate long-term management, three out of seven cases died of multi-organ failure. Background immunodeficiency after allo-HSCT and transplant-related comorbidities may be attributable to subsequent poor prognosis.