Mycobacterium haemophilum is a slow-growing non-tuberculous mycobacterium (NTM) that occurs especially in individuals with conditions that compromise cellular immunity, such as transplant recipients and patients with acquired immunodeficiency syndrome. A 24-year-old male patient was admitted to a tertiary hospital with complaints of dry cough, weight loss, undocumented fever, and skin lesions for one year. Eight years earlier, he had undergone kidney transplantation due to a solitary kidney and was currently receiving immunosuppressive therapy with mycophenolate mofetil and prednisone. On physical examination, he was oriented, underweight, pale, dyspneic, and presented pustular lesions on the head and neck. Computed tomography (CT) showed multiple diffusely distributed centrilobular pulmonary micronodules associated with mediastinal and hilar lymphadenopathy. Cervical and supraclavicular lymphadenopathy was also present, as well as lymph node conglomerates at the mesenteric root, hepatic hilum, peripancreatic region, and retroperitoneum. Screening for opportunistic infections revealed only a positive M band on histoplasmosis serology, and IGRA-TB was negative. Acid-fast bacilli (AFB) and fungal investigations, as well as PCR for M. tuberculosis and H. capsulatum , were negative in bronchoalveolar lavage. Cervical lymph node biopsy showed chronic granulomatous lymphadenitis. The patient was treated with liposomal amphotericin B, but symptoms persisted after two weeks of therapy. After 42 days of incubation, growth of Mycobacterium haemophilum was identified in a peripheral blood culture collected at admission. Treatment with moxifloxacin, rifampicin, and clarithromycin was initiated, with good clinical response and subsequent hospital discharge. Disseminated atypical mycobacterial infections should be considered in the differential diagnosis of immunosuppressed patients presenting with granulomatous diseases and multiple lymphadenopathies, in addition to fungal infections and tuberculosis. As in the present case, diagnosis may be challenging due to low bacterial burden and slow growth, particularly in the absence of widely available molecular methods.
Bonato et al. (Sun,) studied this question.