Evaluation of the in vitro activity of cefepime compared to other broad-spectrum cephalosporins against clinical isolates from eighteen Brazilian hospitals by using the Etest

Abstract

The in vitro activity of cefepime was compared to that of ceftazidime, ceftriaxone, and cefotaxime in a multicenter study involving 10 clinical microbiology laboratories and clinical isolates from 18 Brazilian hospitals from 7 cities (4 states). A total of 982 isolates consecutively collected between December 1995 and March 1996 were susceptibility tested by using Etest and following the NCCLS procedures for agar diffusion tests. The cefepime spectrum was broader than that of the other broad-spectrum cephalosporins against both Gram-negative rods and Gram-positive cocci. Cefepime was particularly more active against Enterobacter sp. (MIC 90, 2 μg/ml), Serratia sp. (MIC 90, 2 μg/ml) and oxacillin-susceptible Staphylococcus aureus (MIC 90, 3 μg/ml). Against Pseudomonas aeruginosa, cefepime (MIC 90, 16 μg/ml) was slightly more active than ceftazidime (MIC 90, 32 μg/ml) and 8- to 16-fold more active than ceftriaxone or cefotaxime (MIC 90′ >256 μg/ml). Our results show that nosocomial bacteria, especially Gram-negative rods, have a high rate of cephalosporin resistance in Brazil. However, part of these resistant bacteria remains susceptible to cefepime. The Etest was shown to be an excellent method for multicenter studies of the in vitro evaluation of new antimicrobial agents.