• Qian Guo, Jianhao Wei, Wenda Zou, Qiongxian Li, Xueqin Qian, and Zhaoqin Zhu.
• Department of Clinical Laboratory, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, People's Republic of China; Department of Molecular Biology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, People's Republic of China.
• J Glob Antimicrob Resist. 2021 Jun 1; 25: 72-76.

ObjectivesThe aim of this study was to compare the antibiotic susceptibility profiles of Mycobacterium abscessus complex (MABC) isolates and to investigate the relationship between susceptibility profiles and genetic mechanisms of macrolide resistance.MethodsMore than 200 isolates collected from respiratory specimens between 2014 and 2018 were randomly analysed in this study. Minimum inhibitory concentrations (Mics) of ten potential antimicrobial agents were determined by the microplate alamarBlue assay.ResultsWe identified 43 MABC isolates, including 32 M. abscessus subsp. abscessus (M. abscessus) (6 from immunocompromised patients) and 11 M. abscessus subsp. massiliense (M. massiliense). The majority of MABC isolates were susceptible to amikacin (96.9% and 100.0% for M. abscessus and M. massiliense, respectively), linezolid (96.9% and 100.0%, respectively), cefoxitin (100.0% and 100.0%, respectively), imipenem (90.6% and 72.7%, respectively) and tobramycin (90.6% and 72.7%, respectively). The resistance rates to clarithromycin and doxycycline in isolates of M. abscessus (68.8% and 100.0%) were significantly higher than those in isolates of M. massiliense (18.2% and 63.6%) (P < 0.05), whereas the percentage of tobramycin-resistant isolates among M. abscessus (9.4%) was significantly lower than among M. massiliense (27.3%) (P = 0.007). Sequencing analyses showed significant differences between erm(41) of M. abscessus and M. massiliense.ConclusionMycobacterium abscessus is the dominant pathogen of pulmonary MABC infections in our hospital. Aminoglycosides (amikacin and tobramycin), β-lactams (cefoxitin and imipenem) and linezolid exhibited potent inhibitory activity against MABC in vitro. The erm(41) gene may be a promising marker to predict macrolide susceptibility for M. abscessus.Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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