In vitro evaluation of broad-spectrum beta-lactams in the Philippines medical centers: Role of fourth-generation cephalosporins

Cefepime is a potent broad-spectrum "fourth generation" cephalosporin. The in vitro activity of cefepime was compared to that of cefpirome, ceftazidim e, ceftriaxone, imipenem, and piperacillin/tazobactam in a multilaboratory (Mine medical centers) Philippine surveillance project from March through O ctober 1998. A total of 626 Grain-positive and Gram-negative organisms (10 species groups) were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by current quality control strain analysis. The ove rall rank order of usable spectrum of activity was imipenem (4.2% resistanc e), cefepime (4.5%), cefpirome (5.0%), piperacillin/tazobactam (5.8%) > cef triaxone (11.2%) > ceftazidime (15.3%), and results did not differ signific antly between medical centers. Ceftazidime-resistant Escherichia coli and K lebsiella spp. occurred at rates of 13.3% and 31.1%, respectively, indicati ng extended-spectrum beta-lactamase (ESBL) activity. Imipenem (100% suscept ible), cefepime, and cefpirome (both greater than or equal to 97.8% suscept ible) were active in vitro against these ESBL phenotypes. Organisms with ce ftazidime and/or ceftriaxone-resistant profiles consistent for hyper-produc tion of Amp C cephalosporinases were detected at high rates among the Citro bacter spp. (29.2%) and Enterobacter spp. (45.8%); however, imipenem (100.0 % susceptible) and cefepime (98.9%) remained active. Cefepime and imipenem (both 87.5% susceptible) were the most active agents tested against Acineto bacter spp. whereas piperacillin/tazobactam was most effective against P. a eruginosa (80.0% susceptible). Most tested beta-lactams (except ceftazidime ) were active versus oxacillin-susceptible staphylococci. These data should be used as a guide for treatment selection with beta-lactam compounds in t he Philippines and to serve as a resistance benchmark in comparisons with f uture studies in this nation. (C) 1999 Elsevier Science Inc.