IN-VITRO ANTIBACTERIAL ACTIVITY OF CEFEPIME - A MULTICENTER STUDY

The antimicrobial activity of cefepime, a new broad-spectrum parenteral cephalo-sporin, was evaluated in vitro against 1757 recent clinical Gram-positive and Gram-negative isolates. Cefepime was active at low concentrations (MIC50 values ≦ 0·06 mg/L and MIC90 values ≦ 012 mg/L) against non-cephalosporinase-producing Enterobacteriaceae (Escherichia coli, Proteus mirabilis. Salmonella spp. and Shigella spp.) For Klebsiella pneumoniae, MICs were between 0·016 and 16 mg/L; the highest MIC values were observed for extended-spectrum β-lactamase-producing strains. Against Enterobacteriaceae, such as cephalosporinase producing Enterobacter cloacae, MICs were ≦ 05 mg/L, but MICs against cephalosporinase hyperproducing strains were generally higher. Ticarcillin-sensitive strains of Pseudomonas aeruginosa were inhibited by cefepime concentrations of 0·5–16 mg/L, while cefepime MICs were 8–64 mg/L for strains resistant to ticarcillin. The cefepime MIC.50, value for Haemophilus spp. including many resistant to amoxycillin, was 0·03 mg/L. Against methicillin-sensitive strains of Staphylococcus aureus, cefepime MICs were 0·05–16 mg/L; MICs against methicillin-resistant staphylococci were 16−>128 mg/L). Against methicillin-sensitive coagulase-negative staphylococci, cefepime MIC values were 0·03–16 mg/L; corresponding values for methicillin-resistant strains were 2–128 mg/L. Streptococci (Groups A, C and G) were sensitive to cefepime with MICs ranging from ≦ 0·008–2 mg/L (MIC50, 0·03 mg/L; MIC90, 0·25 mg/L). The activity of cefepime against Group B streptococci and pneumococci were comparable, with MIC50 values of 0·12 and 0·25 mg/L, respectively, and MIC90 values of 0·03 and 0·25 mg/L, respectively. Most enterococci and all Listeria monocytogenes strains had MICs ≧ 32 mg/L. Among the anaerobes, Clostridium perfringens and the Peptostreptococcus spp. were highly sensitive to cefepime while the Bacteroides spp. generally had MICs ≧ 32 mg/L. Overall, cefepime was highly active against Enterobacteriaceae including cephalo-sporinase-producing strains but its activity was variably diminished against cephalo-sporinase-hyperproducing or extended-spectrum β-lactamase producing strains. Cefepime was active against methicillin-sensitive staphylococci and demonstrated activity comparable to that of ceftazidime against P. aeruginosa. © 1993 The British Society for Antimicrobial Chemotheraphy.