<i>In Vitro</i> Synergy Testing of Eravacycline in Combination with Clarithromycin and Rifabutin against Mycobacterium abscessus Complex

The Mycobacterium abscessus complex (MabsC) is a group of multidrug-resistant nontuberculous mycobacteria (NTM) which may cause pulmonary and extrapulmonary infections (1). It consists of three subspecies: Mycobacterium abscessus, Mycobacterium massiliense, and Mycobacterium bolletii. Treatment outcomes are often poor, with clarithromycin susceptibility (largely mediated by the erm41 gene) being one of the key factors influencing treatment outcome (2, 3). Clarithromycin is usually recommended as the key drug in treatment regimens and is used in combination with other antibiotics based on antimicrobial susceptibility testing (4). However, the organism is often resistant to various antibiotics (5), and there is interest in exploring new antimicrobials with potential antimycobacterial activity against MabsC.