Disseminated Mycobacterium genavense infection in a patient with a history of sarcoidosis

We present a case of Mycobacterium genavense infection in a man in his 60s with a history of sarcoidosis, treated for 24 years with systemic corticosteroids and later methotrexate as monotherapy. He presented with low grade fever, dyspnoea and right-sided thoracic pain and was admitted due to a treatment-refractory infection. After a prolonged period of symptoms and diagnostics, acid-fast bacilli were demonstrated in pleural fluid and PCR revealed M. genavense. The patient was treated with intravenous amikacin, peroral azithromycin, rifampicin and ethambutol for a total of 18 months, with a good clinical and radiological treatment response. Infection with M. genavense is rare in HIV-negative immunocompromised hosts. Diagnosing and treating mycobacterial infections, especially for more rare species, remains a challenge as clinical evidence is sparse. Nonetheless, the disease-causing infection must be considered in symptomatic and immunocompromised patients.