[Inhibitory and fatal activity of amoxicillin, erythromycin and josamycin against Streptococci].

23 Streptococcus sp. of different serological groups were assayed to evaluate the susceptibility to amoxycillin, erythromycin and josamycin. Inhibitory (CMI) and bactericidal (CMB) activity were compared to minimal lethal concentration (CML) observed at different times from the beginning of incubation to study the kinetic of lethal effect of the three antibiotics. Erythromycin shows an earlier bactericidal efficacy against most of the strains assayed. CMB and CML evaluated after 18 hours of incubation are generally similar, while CML against Streptococci group G, Streptococci group D assayed with macrolides and CML against alpha-haemolytic Streptococci assayed with amoxycillin are higher.