Rapidly growing mycobacteria in TB/HIV co-infection: a report of two cases focusing on difficulties in diagnosis and management

Recent reports indicate an increase in rates of infection and disease due to rapidly growing mycobacteria (RGM) in patients with pre-existing chronic lung disease. Studies have described difficulties in correctly identifying closely related species, even when proper methodologies are adopted, and several different gene targets have been proposed. We describe two cases of RGM infection in a 29-year-old HIV-1 positive Congolese man and a 19-year-old HIV-1 positive Liberian woman, respectively, both with bronchiectasis due to previous Mycobacterium tuberculosis (MTB) infection. Mycobacterium porcinum and Mycobacterium bolletii were identified in bronchoalveolar lavage fluid and sputum, respectively. After starting the patients on antiretroviral treatment and primary prophylaxis against non-tuberculous mycobacteria (NTM), and ensuring that they adhered to their prescribed regimen, we observed an improvement in their clinical condition and mycobacteria cleared from their respiratory specimens. Management of RGM respiratory infection in immunocompromised patients has to be evaluated on a case-by-case basis, taking into account the patient's pulmonary sequelae, adherence to multiple treatments and immune profile.