The time-kill method was used to determine the bactericidal activity of cefditoren compared with oral cephalosporins, amoxicillin, amoxicillin/clavulanate and levofloxacin against a randomly selected group of strains isolated from community-acquired respiratory tract infections (CARTIs). Cefditoren was the only agent showing significant bactericidal activity (>or=3 log(10 )reduction of viable cells) within 4 h against all Streptococcus pneumoniae strains, both penicillin-susceptible (PEN S) or -resistant (PEN R), as well as against Streptococcus pyogenes, and Moraxella catarrhalis. Against beta-lactamase positive strains of Haemophilus influenzae, cefditoren was comparable to the quinolone and more active than other cephalosporins at 24 h. Cefditoren showed the best killing kinetic profiles and this observation may be important when choosing an oral third-generation cephalosporin as initial or sequential therapy.