Antibacterial activity of temocillin

The in vitro antibacterial activity of temocillin, a new penicillin, was determined in quantitative broth dilution tests, and compared with that of mezlocillin, piperacillin, cephazolin and cefotaxime. 805 clinical isolates of the Enterobacteriaceae family were tested, with temocillin exhibiting a high level of antibacterial activity against the various bacterial species, including mezlocillin-resistant strains. With the exception of Serratia marcescens, the minimum inhibitory concentrations (MICs) of 90% of tested strains of various species were in the range of 1 to 8 mg/L temocillin. Concentrations of 16 mg/L were required to inhibit 80% of S. marcescens strains, and some isolates were resistant. Significant differences between the MIC and MBC values were not observed. Furthermore, the pharmacokinetics of the bactericidal action of temocillin against mezlocillin-resistant strains was investigated, and killing curves showed that the compound was bactericidal at the MIC and the MBC.