[In vitro antibacterial activity of cefodizime (HR 221) on 323 hospital strains of Gram negative bacilli. Comparison with cefotiam, cefoperazone, cefotetan and cefotaxime].

In vitro activity of a new cephalosporin, cefodizime, was investigated by comparison with cefotiam, cefoperazone, cefotetan and cefotaxime. 291 Enterobacteriaceae strains belonging to 6 cephalosporin-resistance phenotypes and 32 strains of oxidative Gram negative bacilli were tested. With modal MICs of 0.25 to 4 mg/l, cefodizime is active on most phenotypes of resistance to first or second generation cephalosporins demonstrated in vitro in Enterobacteriaceae, including strains resistant to cefamandole and intermediate to cefoxitin. Cefodizime fails to inhibit strains resistant to third generation cephalosporins (E. cloacae, C. freundii, P. stuartii), except for those strains of S. marcescens belonging to this phenotype whose modal MIC is 4 mg/l. 85% of all tested Enterobacteriaceae are inhibited by 4 mg/l and 91% by 8 mg/l. Cefodizime exhibits little activity against A. calcoaceticus and P. aeruginosa. Comparison of activities of the five cephalosporins against Enterobacteriaceae shows that cefodizime out-strips cefotiam, cefoperazone and cefotetan as a result of its broader spectrum of activity against tested species. Cefotaxime, on the contrary, proves superior to cefodizime and is still the most potent drug against. A. calcoaceticus whereas cefoperazone has the greatest effectiveness against P. aeruginosa.