Antibacterial activity of cefpodoxime in vitro

Cefpodoxime proxetil is a new orally administered prodrug which is absorbed and de-esterified by the intestinal mucosa to release the third-generation cephalosporin, cefpodoxime, and 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 oral cephalosporins and quinolones against 637 recent clinical isolates from Kaohsiung Veterans General Hospital in Taiwan. Against Escherichia coli and Klebsiella pneumoniae, cefpodoxime showed excellent activity, inhibiting over 90% of these isolates at 1 mg/l. Like other oral drugs of its class, it had little activity against Pseudomonas aeruginosa and Acinetobacter spp. Against Haemophilus influenzae, irrespective of beta-lactamase production, its activity was similar to comparative drugs. Against methicillin-susceptible Staphylococcus aureus, cefpodoxime showed moderate activity, inhibiting 90% of these isolates at 4 mg/l, whereas it was inactive against methicillin-resistant S. aureus. However, all cephalosporins have shown little in vivo activity against methicillin-resistant S. aureus regardless of in vitro results. Cefpodoxime was inactive against Enterococcus spp. Against other streptococci, its activity was similar to other oral cephalosporins and quinolones tested. The results of this in vitro study indicated that oral administration of cefpodoxime should be an ideal agent in the empirical outpatient treatment for community-acquired cutaneous, respiratory and urinary tract infections.