Comparative in vitro activity of cefpirome and cefepime, two new cephalosporins

In in vitro tests the broad-spectrum cephalosporins cefpirome and cefepime were highly active against Enterobacteriaceae, although often less so against strains resistant to amoxicillin-clavulanate and ticarcillin-clavulanate, and against most strains of Acinetobacter spp. and Aeromonas hydrophila. They were also active against Pseudomonas aeruginosa, although strains with non-plasmid mediated beta-lactam resistance were sometimes less sensitive. Other Pseudomonas spp. varied in their sensitivity. Both agents were highly active against Haemophilus influenzae, but beta-lactamase-producing Branhamella catarrhalis were somewhat less sensitive. Neisseria gonorrhoeae were susceptible, although non-beta-lactamase producing penicillin-resistant strains had higher MICs. Gardnerella vaginalis was also susceptible and Campylobacter coli/jejuni usually susceptible. Both antibiotics had good activity against Staphylococcus aureus and coagulase-negative staphylococci except for methicillin-resistant strains and Staphylococcus haemolyticus which were of borderline sensitivity. All streptococci were sensitive, with the exception of highly penicillin-resistant pneumococci and enterococci against which cefpirome had greater activity than cefepime. Both antibiotics had little useful activity against the Bacteroides fragilis group or Bacteroides oralis group but were active against most other anaerobes. Clostridium difficile and some other Clostridium species were resistant.