The Antimicrobial Activity of Linezolid Against Unconventional Pathogens

Linezolid is an oxazolidinone antibiotic that is mainly permitted to treat Gram-positive bacterial infections. Recent studies have shown that linezolid also has antibacterial effects on several other bacteria outside the package insert, including , non-tuberculous mycobacteria (NTM), , , and anaerobes, . Interestingly, linezolid also has an inhibitory effect on fungi. This review focuses on the antibacterial activity of linezolid against microorganisms outside its antibacterial spectrum. We mainly listed the number of the tested strains, the minimum inhibitory concentration (MIC) range, MIC, and MIC of linezolid against those pathogens outside the package insert. The results showed that among these tested pathogens, linezolid displayed strong inhibitory effects against , , and , with an MIC range of ≤2 μg/mL. As for NTM, linezolid exhibited moderate to potent inhibitory effects against the strains of different species with an MIC range of 0.06-128 μg/mL. Moreover, linezolid was reported to have a species-dependent inhibitory effect on anaerobes at a concentration range of 0.003-16 μg/mL. Furthermore, linezolid could enhance azoles and amphotericin B's antifungal activity on synergistically. It is hoped that this analysis can provide data for expanding the application of linezolid, make the off-label drug use have more compelling evidence, and provide clues for the development of new drugs.