Disseminated Mycobacterium tilburgii infection complicated by pulmonary non-tuberculosis mycobacteriosis in a patient with acquired immunodeficiency syndrome: A case report and literature review

Rationale: Mycobacterium tilburgii is the causative agent of disseminated non-tuberculosis mycobacterial infections in individuals who are immunocompromised, including those with human immunodeficiency virus infection. Owing to its non-culturable nature, identification of M. tilburgii relies solely on genetic analysis, making reports of M. tilburgii infections rare. We report a case of disseminated M. tilburgii infection complicated by a mixed pulmonary non-tuberculosis mycobacterial infection in a patient with acquired immunodeficiency syndrome. Patient concerns: A male patient in his 40s, diagnosed with human immunodeficiency virus, was admitted with suspected disseminated non-tuberculosis mycobacterial infection based on initial laboratory findings and mycobacterial testing. Mycobacterium intracellulare and Mycobacterium kansasii were detected in the respiratory specimens. Acid-fast staining of the blood and bone marrow samples was positive; however, no bacterial growth was observed in the cultures. Genetic analysis of the blood and bone marrow samples revealed the presence of M. tilburgii . Diagnoses: The patient was diagnosed with disseminated M. tilburgii infection, accompanied by a mixed pulmonary non-tuberculosis mycobacterial infection. Enterococcus faecium , Candida parapsilosis , and Candida glabrata were also detected in blood cultures. Outcomes: Despite ongoing treatment with antibiotics and antifungals, the patient died of septic shock. Lessons: Mycobacterium tilburgii is non-culturable; therefore, when acid-fast bacilli are detected in smear microscopy without subsequent culture growth, clinicians should consider the possibility of M. tilburgii infection and conduct thorough investigations.