Different clinical features of patients with pulmonary disease caused by various Mycobacterium avium-intracellulare complex subspecies and antimicrobial susceptibility

Objectives: Characteristics of the Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) caused by distinct subspecies remain uncertain. Methods: This study was conducted from 2013-2015 in three hospitals in Taiwan. Results: Among the 144 patients with MAC-PD, 57 (39.6%), 37 (25.7%), 37 (25.7%), and 13 (9.0%) were infected with Mycobacterium intracellulare subspecies intracellulare (MAsH), Mycobacterium avium subspecies hominissuis (MAsH), Mycobacterium intracellulare subspecies chimaera (MIsC), and others, respectively. Patients with MAsH-PD were younger (p = 0.010) with higher human immunodeficiency virus infection rates (27.0%, 0.0%, 0.0%, and 7.7% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p <0.001). Twenty-two (15.3%) patients reported spontaneous culture-negative conversion, but 15 (10.4%) and 33 (22.9%) patients developed radiographic progression and unfavorable outcomes, especially MAsH-PD. The susceptibility rates to clarithromycin and inhaled amikacin were both 98.6%. MAsH demonstrated the lowest rate of resistance to moxifloxacin (66.7%, 97.3%, 89.1%, and 92.3% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p = 0.001) and MIsI isolates had the highest rate of resistance to intravenous amikacin (25%, 13.5%, 38.2%, and 15.4% for MAsH-PD, MIsC-PD, MIsI-PD, and others, respectively; p = 0.024). Conclusions: Pulmonary disease caused by distinct MAC subspecies had different outcomes and drug susceptibility. The local prevalence of species needs to be monitored. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.