Minimal inhibitory concentrations and minimal bactericidal concentrations of quinupristin/dalfopristin against clinical isolates of Corynebacterium jeikeium and Listeria monocytogenes.

Thirty clinical isolates of Listeria monocytogenes and 30 clinical isolates of Corynebacterium jeikeium were tested against quinupristin/dalfopristin by the NCCLS broth macrodilution technique for determination of MICs. MBC testing was also performed on the 60 isolates. Quinupristin/dalfopristin MIC90 values against L. monocytogenes and C. jeikeium were 1.6 mg/L and 0.2 mg/L, respectively. Quinupristin/dalfopristin was bacteriostatic against these organisms.