Author/Authors :
Kim, Min-Jeong Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Kim, Kyu-Min Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Shin, Jeong-Ih Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Ha, Jong-Hun Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Lee, Dong-Hae Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Choi, Jeong-Gyu Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Park, Jin-Sik Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Byun, Jung-Hyun Department of Laboratory Medicine - Gyeongsang National University Hospital, Republic of Korea , Yoo, Jung-Wan Department of Internal Medicine - Gyeongsang National University Hospital, Republic of Korea , Eum, Seokyong International Tuberculosis Research Center - Changwon, Republic of Korea , Jung, Myunghwan Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Chul Baik, Seung Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Lee, Woo Kon Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Lyun Kang, Hyung Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea , Shin, Min-Kyoung Department of Microbiology - College of Medicine - Gyeongsang National University, Republic of Korea
Abstract :
Background
Nontuberculous mycobacteria (NTM) are widely present in environments, such as soil and water, and have recently been recognized as important pathogenic bacteria. The incidence of NTM-related infections is steadily increasing. As the diagnosis and treatment of NTM infection should be distinguished from tuberculosis, and the treatment should be specific to the species of NTM acquired, accurate species identification is required.
Methods
In this study, two-step multiplex PCR (mPCR) and multigene sequence-based analysis were used to accurately identify NTM species in 320 clinical isolates from Gyeongsang National University Hospital (GNUH). In particular, major mycobacterial strains with a high isolation frequency as well as coinfections with multiple species were diagnosed through two-step mPCR. Multigene sequencing was performed to accurately identify other NTM species not detected by mPCR. Variable regions of the genes 16S rRNA, rpoB, hsp65, and 16S-23S rRNA internal transcribed spacer were included in the analysis.
Results
Two-step mPCR identified 234 (73.1%) cases of M. intracellulare, 26 (8.1%) cases of M. avium subsp. avium, and 13 (4.1%) cases of M. avium subsp. hominissuis infection. Additionally, 9 (2.8%) M. fortuitum, 9 (2.8%) M. massiliense, 2 (0.6%) M. abscessus, and 4 (1.2%) M. kansasii isolates were identified. Coinfection was identified in 7 (2.2%) samples. The sixteen samples not classified by two-step mPCR included 6 (1.9%) cases of M. chimaera, 4 (1.3%) M. gordonae, 1 (0.3%) M. colombiense, 1 (0.3%) M. mageritense, and 1 (0.3%) M. persicum identified by sequence analysis.
Conclusions
The results of this study suggest a strategy for rapid detection and accurate identification of species using two-step mPCR and multigene sequence-based analysis. To the best of our knowledge, this study is the first to report the identification of NTM species isolated from patients in Gyeongnam/Korea.
