In vitro evaluation of the antibacterial activity of nemonoxacin against Mycobacterium abscessus

Abstract

Objective: To evaluate the in vitro antibacterial activity of nemonoxacin against clinical isolates of Mycobacterium abscessus (M. abscessus). Methods: A total of 194 clinical strains of M. abscessus were collected from 2014 to 2017 in Shanghai Pulmonary Hospital. The minimum inhibitory concentrations (MICs) of nemonoxacin and other quinolones commonly used (moxifloxacin, levofloxacin and ciprofloxacin) against M. abscessus in clinic was determined by the micro-broth dilution method. Synergy between nemonoxacin and frequently used anti-M. abscessus drugs (clarithromycin, amikacin, imipenem, cefoxitin, tigecycline and linezolid) was assessed in vitro. Results: The MIC range of nemonoxacin to M. abscessus was 0.25-64.00 mg/L. The MIC50 and MIC90 were 4 and 16 mg/L, respectively. Most M. abscessus isolates demonstrated an MIC of ≤ 4 mg/L against nemonoxacin, with a percentage of 68.0% (132/194), which was significantly higher than that against moxifloxacin (51.0%, 99/194; χ2 = 11.651, P<0.01), ciprofloxacin (46.4%, 90/194; χ2 = 18.572, P<0.01) and levofloxacin (25.8%, 50/194; χ2 = 69.586, P<0.01), respectively. Nemonoxacin showed no antagonistic effect with commonly used anti-M. abscessus drugs, except imipenem. Conclusions: Nemonoxacin showed moderate in vitro antibacterial activity against M. abscessus, which was better than that of other fluoroquinolones commonly used in clinic at present. Therefore, nemonoxacin may be one of the options for combined treatment of M. abscessus infection.