Comparative In Vitro Killing Activities of Meropenem, Imipenem, Ceftriaxone, and Ceftriaxone plus Vancomycin at Clinically Achievable Cerebrospinal Fluid Concentrations against Penicillin-Resistant Streptococcus pneumoniae Isolates from Children with Meningitis

The activities of meropenem, imipenem, ceftriaxone, and vancomycin were evaluated against 80 penicillin-susceptible and -resistant Streptococcus pneumoniae strains. Meropenem, imipenem, ceftriaxone, and vancomycin MICs at which 90% of the isolates are inhibited were 0.5, 0.25, 1, and 0.25 μg/ml, respectively. Against penicillin-resistant strains, the best killing activity at cerebrospinal fluid concentrations was obtained with imipenem and ceftriaxone-vancomycin. However, while the killing activity of imipenem was significantly greater than that of meropenem, no significant difference was observed between the activities of meropenem and ceftriaxone-vancomycin.