Levels of resistance to the "third-generation" cephalosporins among isolates of clinical bacteria in Korea have been increasing at a vapid rate. This study evaluated the activity of cefepime, a "fourth-generation" cephalosporin, and six other broad-spectrum beta-lactam antimicrobials (cefpirome, ceftazidime, ceftriaxone, imipenem, piperacillin/tazobactam [4 mu g/mL fixed concentration], oxacillin) against 404 isolates of clinical bacteria from Korea. Susceptibility profiles of each isolate were established using the Etest (AB BIODISK, Solna, Sweden) method of susceptibility testing. Only the carbapenem imipenem was > 90% effective irt inhibiting each of the species tested (Escherichia coli, Klebsiella, spp., Citrobacter spp., Enterobacter spp., indole-positive Proteae, Serratia spp., Acinetobacter spp., Pseudomonas aeruginosa, and oxacillin-susceptible staphylococci). Imipenem runs followed by cefepime > cefpirome > piperacillin/tazobactam > ceftazidime > ceftriaxone in overall rank older of usable spectrum against the isolates tested. Extended spectrum beta-lactamase producing phenotypes were much more prevalent among the Klebsiella spp. (48.8%) than the E. coli (5.0%) isolates. Cefepime was much move active than cefpirome, 95.1% susceptible as compared with 70.7% susceptible, against the 41 isolates of Klebsiella spp. The results of this study corroborates findings from earlier studies with levels of resistance to the broad-spectrum beta-lactams in Korea continuing to rise indicating the need for intervention strategies. (C) 1999 Elsevier Science Inc.