COMPARATIVE IN-VITRO ACTIVITY OF NEWER CEPHALOSPORINS

Object: To determine the in vitro activity of six new cephalosporins. Design: Determination of minimum inhibitory concentration of new drugs and their comparison with commercially available cephalosporins in cl inical use against recent clinical isolates. Setting: King Faisal Spec ialist Hospital and Research Centre, Riyadh (KFSH & RC), Saudi Arabia. Bacteria: 897 bacteria recently isolated from clinical specimens of p atients at KFSH & RC. Results: Cefepime, cefpirome, GR 691 53 and Ro 0 9-1428 were the most active agents against Enterobacteriaceae and Aero monas hydrophila, inhibiting > 90% of them at less-than-or-equal-to 0. 5 mg/l. Ro 09-1428 had the most potent activity against Pseudomonas ae ruginosa followed by cefepime, GR 69153 and cefpirome. Cefdinir and RU 29 246 were ineffective against pseudomonads and xanthomonads. All th e six were inhibitory towards streptococci and methicillin-susceptible Staphylococcus aureus. Cefdinir and cefpirome were the only cephalosp orins with any appreciable activity against enterococci. Conclusions: Newer parenteral cephalosporins were more active against Enterobacteri aceae than orally active agents. Ro 09-1428, cefepime and GR 691 53 ha d excellent activity against P. aeruginosa. All were active against st reptococci and methicillin-susceptible S. aureus.