<i>Mycobacterium intracellulare</i> M.i.198—A Promising Strain for Studying Pathogenesis of Nontuberculous Mycobacterial Pulmonary Disease (NTM‐PD)

In this review, we introduce a promising strain for studying pathogenesis of nontuberculous mycobacterial pulmonary disease (NTM-PD), Mycobacterium intracellulare M.i.198. M.i.198 was isolated from a patient with progressive Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) in whom surgical operation was required to suppress disease progression. M.i.198 shows progressive illness in infected mice in terms of bacterial load, inflammation, and by high-dose inoculation, mortality as well. Although M.i.198 is resistant to clarithromycin, the pathogenicity of M.i.198 in mice indicates the high potency for use to evaluate drug efficacies in vivo. Furthermore, M.i.198 can be genetically manipulated, which is quite different from other MAC strains, especially those of M. avium subsp. hominissuis. We herein report the bacteriological findings, experimental virulence and functional genomic features of M.i.198 with a small review of MAC strains used for animal models of MAC-PD.