Comparative anti-gonococcal activity of S-565, a new rifamycin.
The in vitro activity of S-565, a semi-synthetic rifamycin chemically related to rifampicin but with a longer half-life, has been compared with that of rifampicin, ciprofloxacin, spectinomycin, azithromycin and amoxycillin against Neisseria gonorrhoeae. Modal MICs against 20 strains were 0.13 mg/l for rifampicin and 0.5 mg/l for S-565. There was cross-resistance between the two rifamycins, and each selected for resistance at similar rates. In a time-kill study, S-565 was more rapidly bactericidal than rifampicin at x 1 and x 2 MIC.
Hamilton-Miller
J M
JM
Department of Medical Microbiology, Royal Free Hospital School of Medicine, Pond St., London NW3 2QG, UK.
Bruzzese
T
T
Nonis
A
A
Shah
S
S