In VitroSusceptibility Testing of Tedizolid against Nontuberculous Mycobacteria.
Tedizolid is a new oxazolidinone with improvedin vitroand intracellular potency againstMycobacterium tuberculosis, including multidrug-resistant strains, and some species of nontuberculous mycobacteria (NTM) compared with that of linezolid. Using the current Clinical and Laboratory Standards Institute (CLSI)-recommended method of broth microdilution, susceptibility testing of 170 isolates of rapidly growing mycobacteria showed equivalent or lower (1- to 8-fold) MIC50and/or MIC90values for tedizolid compared with that for linezolid. The tedizolid MIC90values for 81 isolates ofM. abscessussubsp.abscessusand 12 isolates ofM. abscessussubsp.massiliensewere 8 μg/ml and 4 μg/ml, respectively, compared with linezolid MIC90values of 32 μg/ml for both. The MIC90values for 20 isolates ofM. fortuitumwere 2 μg/ml for tedizolid and 4 μg/ml for linezolid. Twenty-two isolates ofM. chelonaehad tedizolid and linezolid MIC90s of 2 μg/ml and 16 μg/ml, respectively. One hundred forty-two slowly growing NTM, including 7/7M. marinum, 7/7M. kansasii, and 7/11 of other less commonly isolated species, had tedizolid MICs of ≤1 μg/ml and linezolid MICs of ≤4 μg/ml. One hundred isolates ofMycobacterium aviumcomplex and eightM. simiaeisolates had tedizolid MIC50s of 8 μg/ml and linezolid MIC50s 32 and 64 μg/ml, respectively. NineM. arupenseisolates had MIC50s of 4 μg/ml and 16 μg/ml for tedizolid and linezolid, respectively. These findings demonstrate a greaterin vitropotency of tedizolid than linezolid against NTM and suggest that an evaluation of tedizolid as a potential treatment agent for infections caused by selected NTM is warranted.
The University of Texas Health Science Center at Tyler, Department of Microbiology, Tyler, Texas, USA barbara.elliott@uthct.edu.
Barbara A
BA
Brown-Elliott
The University of Texas Health Science Center at Tyler, Department of Microbiology, Tyler, Texas, USA.
Richard J
RJ
Wallace
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009170:Nontuberculous Mycobacteria / Q000187:drug effects*; D010755:Organophosphates / Q000494:pharmacology*; D010080:Oxazoles / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D010755:Organophosphates; D010080:Oxazoles; C515040:tedizolid phosphate
oxazolidinones; susceptibility testing; tedizolid