Mycobacterium reverse hybridization line-probe assay used to diagnose disseminated Mycobacterium haemophilum infection in a child with acute lymphoblastic leukemia

Disseminated Mycobacterium abscessus Complex Infection Manifesting as Multiple Areas of Lymphadenitis and Skin Abscess in the Preclinical Stage of Acute Lymphocytic Leukemia

A 37-year-old woman was admitted to a hospital due to a prolonged fever and a rash on her legs. She had systemic lymphadenitis and a skin abscess on her left leg. Pathological findings of a left leg skin biopsy revealed abscess formation with granulomatous dermatitis, Mycobacterium abscessus complex was cultured from the resected left supraclavicular lymph node, and disseminated M. abscessus complex infection was diagnosed. She was treated with combination treatment with antimicrobials and percutaneous drainage, and her clinical findings improved. Four months later, she developed acute lymphocytic leukemia. Leukemia is a risk factor for disseminated M. abscessus complex infection, even before developing leukemia.

Clinical manifestations, diagnosis, and treatment of Mycobacterium haemophilum infections

Mycobacterium haemophilum is a slowly growing acid-fast bacillus (AFB) belonging to the group of nontuberculous mycobacteria (NTM) frequently found in environmental habitats, which can colonize and occasionally infect humans and animals. Several findings suggest that water reservoirs are a likely source of M. haemophilum infections. M. haemophilum causes mainly ulcerating skin infections and arthritis in persons who are severely immunocompromised. Disseminated and pulmonary infections occasionally occur. The second at-risk group is otherwise healthy children, who typically develop cervical and perihilar lymphadenitis. A full diagnostic regimen for the optimal detection of M. haemophilum includes acid-fast staining, culturing at two temperatures with iron-supplemented media, and molecular detection. The most preferable molecular assay is a real-time PCR targeting an M. haemophilum-specific internal transcribed spacer (ITS), but another approach is the application of a generic PCR for a mycobacterium-specific fragment with subsequent sequencing to identify M. haemophilum. No standard treatment guidelines are available, but published literature agrees that immunocompromised patients should be treated with multiple antibiotics, tailored to the disease presentation and underlying degree of immune suppression. The outcome of M. haemophilum cervicofacial lymphadenitis in immunocompetent patients favors surgical intervention rather than antibiotic treatment.

Mycobacterium haemophilum in an immunosuppressed child

Mycobacterium haemophilum is an emerging cutaneous and systemic pathogen in immunosuppressed adults. Reports in the pediatric literature prior to 2004, limited to immunocompetent children with lymphadenitis, offer a different clinical presentation from that of the immunosuppressed adult. We report an instance of this atypical mycobacterial infection occurring in an immunosuppressed boy with clinical findings similar to those described in immunosuppressed adults.