[Kinetics of ofloxacin-amoxicillin and ofloxacin-clavulanic acid combinations against pathogenic bacteria of the respiratory tract].

Ofloxacin exhibit a good activity against the pathogen bacteria of the respiratory tract, except for S. pneumoniae. Its use is interesting because it has a good diffusion into respiratory tissues. However, the combination with an another antibiotic was necessary to spread the activity spectrum and to prevent the resistant variants. By the new killing curve checkerboard method, these 2 combinations are studied against 8 strains: 4 H. influenzae (2 beta-lactamase producers), 2 S. pneumoniae and 2 K. pneumoniae, at 0, 2, 4, 6 and 24 hours, a viable bacteria counting is executed by a microdilution method and is subcultured with a Steers-type multiple inoculator. With K. pneumoniae, ofloxacin has a dose dependent bactericidal activity which is maximum at 1 mg/l, While augmentin has a time-dependent activity. In the combination the synergy is rare. With H. influenzae, the results are the same; the bactericidal activity is less rapid but it is better than the ones with amoxicillin and clavulanic acid. With S. pneumoniae, the 2 antibiotics have the same activity. No antagonism is observed. And the antibiotic which has a better bactericidal activity determine the viable bacteria count.