Antibacterial activity of eight cephalosporins against Haemophilus influenzae and Streptococcus pneumoniae

Two hundred recent clinical isolates of Haemophilus and Pneumococcus were tested in vitro against eight cephalosporins by means of disc diffusion and agar dilution tests. In the case of Haemophilus, the most active drug (cefamandole) was 100 times as active as the least effective one (cephalexin). Many strains were resistant to cephradine and cephalexin. The most active cephalosporins against Streptococcus pneumoniae were cephaloridine, cephapirin, cefazolin, cefamandole and cephalothin. Cefoxitin, cephradine and cephalexin were clearly less active. Nevertheless, none of the strains were clearly resistant to these drugs.