In vitro activities of contezolid (MRX-I) against drug-sensitive and drug-resistant Mycobacterium tuberculosis

A novel oxazolidinone for the treatment of Mycobacterium tuberculosis has been developed, but the activity of contezolid (MRX-I) still needs to be clarified. In this study, we isolated Mycobacterium tuberculosis from 48 clinical patients with pulmonary tuberculosis. Roche drug susceptibility tests identified drug-sensitive and 39 drug-resistant M. tuberculosis isolates. Drug susceptibility assays indicated that MRX-I exhibited anti-Mycobacterium tuberculosis activity against both drug-sensitive and drug-resistant isolates, with an advantage against drug-resistant isolates. The results also showed that the anti-Mycobacterium tuberculosis activity was comparable to that of linezolid. IMPORTANCE Currently, Mycobacterium tuberculosis has exhibited increased drug resistance, leading to ineffective drug treatment in many patients with tuberculosis. Among the anti-Mycobacterium tuberculosis drugs, oxazolidinones have been gradually developed. Contezolid (MRX-I) has been newly developed in China with advantages versus the first oxazolidinone antibiotic approved by the Food and Drug Administration for clinical use, but the anti-M. tuberculosis activity needs to be further clarified. In this study, in vitro activities of MRX-I against M. tuberculosis were tested. The drug susceptibility assays indicated that MRX-I exhibited anti-M. tuberculosis activity comparable to that of linezolid, with an advantage against drug-resistant isolates.