Trend of nontuberculous mycobacteria species and minimal inhibitory concentration in a referral laboratory in Korea from 2013 to 2019

Abstract

BackgroundThis study investigated the trends of nontuberculous mycobacterial (NTM) isolates and the minimal inhibitory concentrations (MIC) of antimicrobial agents in Korea. MethodsData from 2013 to 2019 were collected from 69 medical institutions through 12 branches of the Korean Institute of Tuberculosis. NTM identification was conducted using the Advansure Mycobacteria Genoblot assay. The MIC of antibiotics against NTM species were measured using the broth microdilution method according to the Clinical and Laboratory Standards Institute guidelines. ResultsOver seven years, 86,194 NTM identifications were requested, with an annual increase from 8034 in 2013–17,229 in 2019. The most frequently identified NTM species were M. intracellulare (33,467; 47.3%) and M. avium (19,818; 27.2%), followed by M. abscessus (6858; 9.4%) and M. massiliense (3156; 4.3%). Regarding the antimicrobial agents, imipenem exhibited the greatest difference in MIC between M. intracellulare and M. avium, whereas clarithromycin showed the most significant difference between M. abscessus and M. massiliense. No notable changes were observed in the annual MIC distribution of most antibacterial agents, except for clarithromycin in M. abscessus. ConclusionsThe prevalence of NTM in Korea is gradually increasing, and follow-up studies on NTM isolates identified as the causative agents of infection are needed.