Antimicrobial Susceptibility of Mycobacterium abscessus Complex Clinical Isolates from a Chinese Tertiary Hospital

• Main Authors: Guo Y, Cao X, Yu J, Zhan Q, Yang J, Wu X, Wan B, Liu Y, Yu F
• Format: Article
• Language: English
• Published: Dove Medical Press 2020-06-01
• Series: Infection and Drug Resistance
• Subjects: mycobacterium abscessus complex; resistance; erm(41); synergy; dual β-lactam therapy
• Online Access: https://www.dovepress.com/antimicrobial-susceptibility-of-mycobacterium-abscessus-complex-clinic-peer-reviewed-article-IDR

Yinjuan Guo,1,2 Xingwei Cao,3 Jingyi Yu,4 Qing Zhan,3 Jinghui Yang,1 Xiaocui Wu,1 Baoshan Wan,1 Yin Liu,1 Fangyou Yu1,2 1Department of Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People’s Republic of China; 2Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People’s Republic of China; 3Jiangxi Provincial Key Laboratory of Medicine, Clinical Laboratory of the Second Affiliated Hospital of Nanchang University, Nanchang 330000, People’s Republic of China; 4Department of Laboratory Medicine, Wenzhou Medical University, Wenzhou 325000, People’s Republic of ChinaCorrespondence: Fangyou Yu Email [e-mail]: Mycobacterium abscessus complex (MABC) is a group of important infectious agents that are highly associated with drug resistance, and antibiotic treatment is usually ineffective. This study investigated the characteristics of antimicrobial susceptibility of MABC isolates and the synergy between certain β-lactam combinations against MABC infection.Methods: We collected 129 MABC isolates from patients with lower respiratory tract infections and categorized them into three subspecies. The minimum inhibitory concentrations (MICs) of 15 antimicrobials for the MABC isolates were determined using commercial Sensititre RAPMYCOI MIC plates and the broth microdilution method, as recommended in the CLSI (M24-A2). In addition, the MICs of imipenem, alone and with ceftazidime and/or avibactam, were assessed in vitro for all isolates. The erm(41) and rrl genes were also sequenced.Results: The MABC isolates exhibited > 80% resistance to 11 of the 15 antimicrobials. Regarding the remaining four antimicrobials, the isolates were least resistant to tigecycline (12.4%) and amikacin (3.9%), and only partially resistant to two cefoxitin (39.5%) and imipenem (40.3%). Compared with M. massiliense isolates, M. abscessus and M. bolletii isolates were more resistant to amikacin and imipenem, whereas M. abscessus was significantly less resistant to tigecycline relative to M. massiliense and M. bolletii isolates. The clarithromycin inducible resistance rate was 68.4% and 74.3% among M. bolletii and M. abscessus isolates. Furthermore, 88.7% of the M. abscessus isolates carried a T at position 28 of erm(41), which is associated with inducible clarithromycin resistance. In addition, compared to imipenem with avibactam only, the MIC50 and MIC90values of imipenem after adding ceftazidime plus avibactam were decreased fourfold.Conclusion: The antimicrobial resistance rates and the characteristics of the erm(41) gene associated with inducible clarithromycin resistance were different among the three MABC subspecies. There was also synergy between imipenem and 100μg/mL ceftazidime against MABC isolates.Keywords: Mycobacterium abscessus complex, resistance, erm(41), synergy, dual β-lactam therapy