Rate of bactericidal activity for Streptococcus faecalis of a new quinolone, CI-934, compared with that of amoxicillin.

The rate of bactericidal activity of a new quinolone, CI-934, was compared with that of amoxicillin for 20 strains of Streptococcus faecalis. At 10 and 100 micrograms/ml, the bactericidal activity of CI-934 was more rapid at 6 h than that of amoxicillin. A paradoxical effect (a killing rate higher at 1 microgram/ml than at 100 micrograms/ml at 6 h) was observed for 19 of the 20 strains with amoxicillin and for 1 of the 20 strains with CI-934. It remains to be demonstrated whether in vivo studies will confirm the results obtained in vitro.