Disseminated Mycobacterium abscessus presenting as non-neutropenic fever in a child with acute lymphoblastic leukemia undergoing hematopoietic stem cell transplantation

ABSTRACT Background Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterium that causes disease in both immunocompetent and immunocompromised hosts. Disseminated or invasive infection, although uncommon, is more frequently encountered in immunosuppressed children and presents significant management challenges because of intrinsic antimicrobial resistance, prolonged treatment requirements, and limited pediatric-specific data. Case Summary A 2-year-old male with high-risk pre-B acute lymphoblastic leukemia (ALL) developed isolated non-neutropenic fever during interim maintenance chemotherapy. Initial evaluation was notable only for mild lymphopenia, and blood cultures obtained from an implanted port subsequently grew M. abscessus . Repeat blood cultures remained positive, prompting port removal and initiation of multidrug therapy. Evaluation for disseminated disease revealed bilateral pulmonary nodules and recurrent catheter explant site infection. Susceptibility testing demonstrated macrolide resistance and limited therapeutic options. Management required source control with three surgical debridements and 11 months of combination antimicrobial therapy. During treatment, the patient experienced ALL relapse requiring blinatumomab followed by allogeneic hematopoietic stem cell transplantation. Given evidence of infection control, including negative cultures and radiographic resolution of pulmonary lesions, transplantation proceeded while antimicrobial therapy was continued. The patient successfully completed 5 months of treatment following transplant with sustained clinical improvement. Conclusion Disseminated M. abscessus infection should be considered in immunocompromised children with persistent bacteremia, even in the absence of neutropenia. Successful management requires prompt source control, susceptibility-guided multidrug therapy, and multidisciplinary coordination. This case demonstrates that well-controlled disseminated nontuberculous mycobacterial infection may not preclude hematopoietic stem cell transplantation when ongoing antimicrobial therapy and close monitoring are maintained.