In Vitro Activity of Linezolid against Clinical Isolates of Mycobacterium tuberculosis, including Multidrug-Resistant and Extensively Drug-Resistant Strains from Beijing, China

Abstract

The in vitro activity of linezolid was evaluated against 84 clinical isolates of Mycobacterium tuberculosis, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains, isolated from the center for tuberculosis research and treatment of the Chinese army. Linezolid showed excellent activity, with minimum inhibitory concentrations (MICs) of 0.125–0.5 μg/mL against all tested isolates. There were no differences in the MIC₅₀ and MIC₉₀ of linezolid between susceptible, isoniazid-resistant, MDR, and XDR. Indeed, all of the groups displayed identical MIC₉₀ values of 0.25 μg/mL, which is lower than previously reported in similar studies. We conclude that linezolid may be a more effective drug against M. tuberculosis and may play an important role in treating drug-resistant tuberculosis in China.