Shirata M, Yoshimoto Y, Marumo S, et al. - Given the lack of an established standard treatment regimen against Mycobacteroides abscessus complex (MABC) infections, researchers aimed to develop an active ingredient for the clinical treatment of these infections. Among 102 MABC strains isolated from clinical specimens employing DNA sequence analysis with the housekeeping genes hsp65 and rpoB, there were 51 isolates as M. abscessus, 46 as M. massiliense, and five as others. Using eight antimicrobial agents (clarithromycin, amikacin, doxycycline, imipenem, linezolid, moxifloxacin, faropenem, and rifampicin), they performed drug susceptibility testing against two subspecies, named Mycobacteroides abscessus subsp. abscessus (M. abscessus) and Mycobacteroides abscessus subsp. massiliense (M. massiliense). They employed novel checkerboard method to determine the efficacy of antimicrobial agents. Outcomes revealed additive effects of combinations of imipenem with linezolid, moxifloxacin, and rifampicin against 81.0 %, 40.7 %, and 26.9 % of M. abscessus, respectively, and against 54.5 %, 69.2 %, and 30.8 % of M. massiliense, respectively. The potential efficacy of a regimen containing imipenem is thus suggested against M. abscessus and M. massiliense infections.