Molecular identification and clinical significance of Mycobacterium seoulense strains from patients with nontuberculous mycobacterium infections

Abstract

Purpose: To investigate the clinical significance of Mycobacterium seoulense (M. seoulense) and the ideal gene for species determination.

Methods: Clinical symptoms, laboratory examinations, and radiological examinations were retrospectively reviewed. The hsp65, 16S rRNA, rpoB and ITS region of M. seoulense, were sequenced and phylogenetic trees of mycobacterium strains were constructed.

Results: Four M. seoulense strains isolated from 4 patients caused pulmonary infections based on the symptoms and radiological results. The 16S rRNA sequence identified 2 strains as M. intracellulare and the other 2 as Stenotrophomonas maltophilia. In contrast, the rpoB, 16S-23S inter-region (ITS), and hsp65 sequences shared high identity with M. seoulense. Notably, the phylogenetic tree based on the ITS, hsp65, and rpoB sequences clustered 4 M. seoulense strains identified in this study with M. seoulense strains in the database.

Conclusion: M. seoulense strains can cause infection in humans. They can be identified by sequencing ITS, hsp65, and rpoB genes.

Keywords: 16S rRNA; ITS; Mycobacterium seoulense; hsp65; rpoB; species identification.