Antibacterial activity of cefepime in vitro

Cefepime is a new parenterally active fourth-generation cephalosporin which is undergoing in vitro and in vivo evaluations. Using the standard agar dilution method we compared the in vitro activity of this drug with other cephalosporins and ciprofloxacin against clinical isolates of Escherichia coli (98 strains), Klebsiella pneumoniae (99 strains), Acinetobacter spp. (24 strains), Pseudomonas aeruginosa (98 strains), Haemophilus influenzae (108 strains), Staphylococcus aureus (100 strains), Enterococcus spp. (45 strains), Streptococcus pneumoniae (10 strains), Streptococcus pyogenes (group A; 19 strains) and Streptococcus agalactiae (group B; 36 strains). Cefepime showed excellent activity against E. coli and K. pneumoniae, inhibiting 90% of these isolates at 0.12 mg/l. The in vitro activity of cefepime was superior to or comparable to the third-generation cephalosporins tested but was inferior to ciprofloxacin against Acinetobacter spp. and P. aeruginosa. Against H. influenzae, whether or not the strains produced β-lactamase, its activity was similar to comparable drugs. All 84 isolates of methicillin-susceptible S. aureus were inhibited by 8 mg/l of cefepime whereas, like other cephalosporins, it had little activity against methicillin-resistant S. aureus. Of the 45 enterococci isolates tested, 44.4% were inhibited by 8 mg/l of cefepime. Against streptococci, its activity was superior to any drug tested. This in vitro study indicates that cefepime has the potential to be a valuable agent for the treatment of community- and hospital-acquired cutaneous, respiratory and urinary tract infections.