Resistance selection studies comparing the activity of razupenem (PTZ601) to vancomycin and linezolid against eight methicillin-resistant and two methicillin-susceptible Staphylococcus aureus strains.
Multistep and single-step resistance selection studies were performed with razupenem, linezolid, and vancomycin against 10 methicillin (meticillin)-resistant and -susceptible Staphylococcus aureus strains. After 20 daily subcultures, razupenem yielded only clones with MICs of >4 microg/ml in one strain (8 microg/ml) whose parent's MIC was already 4 microg/ml. After 18 to 49 passages in 6/10 strains, razupenem MICs rose from 0.016 to 2 microg/ml (parents) to 0.125 to 8 microg/ml (with clones stable after 10 drug-free subcultures). Single-step mutant selection frequencies were similarly low for razupenem and comparators.
Department of Pathology, Hershey Medical Center, Hershey, PA 17033, USA.
Catherine
C
Clark
Klaudia
K
Kosowska-Shick
Pamela
P
McGhee
Bonifacio
B
Dewasse
Linda
L
Beachel
Peter C
PC
Appelbaum
D000081:Acetamides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D000069349:Linezolid; D008712:Methicillin / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics; D014640:Vancomycin / Q000494:pharmacology*
D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D014640:Vancomycin; D000069349:Linezolid; D008712:Methicillin