Abstract:
OBJECTIVE To evaluate the in vitro antimicrobial activity of novel oxazolidinones contezolid against linezolid-insensitive Enterococcus (LISE).
METHODS Totally 71 clinical isolates of LISE were collected from the First Medical Center of Chinese PLA General Hospital between 2019 and 2022. The minimum inhibitory concentrations(MICs) of contezolid and linezolid were determined by using broth microdilution method, 6 isolates with MIC of linezolid 4, 8 and 16 mg/L, 2 isolates of each, were selected to compare the minimum bactericidal activity (MBC), serum MIC, killing curve and post-antibiotic effect (PAE) between contezolid and linezolid. The in vitro antibacterial activity of contezolid against the LISE was observed.
RESULTS Contezolid demonstrated good antimicrobial activity against clinical isolates of LISE with varying MICs; the MIC90 of contezolid against Enterococcus faecalis and Enterococcus faecium was 4 mg/L, lower than 8 mg/L of linezolid. Contezolid showed lower MIC than linezolid under the impact of 25% serum protein(P < 0.05). At a concentration of 4 times the MIC, contezolid exhibited favorable antibacterial rate against LISE within 8 to 24 hours. Contezolid showed the lower MIC than linezolid at the similar killing curve; contezolid showed the lower MIC against linezolid-resistant Enterococcus (LRE) than linezolid at the similar PAE, indicating that the antimicrobial activity of contezolid was remarkably higher.
CONCLUSION The in vitro antimicrobial activity of contezolid against LISE is higher than that of linezolid, and contezolid plays an important role in clinical treatment.