Rifampin, ampicillin, streptomycin, and their combinations in the treatment of enterococcal pyelonephritis in rats.

The activities of ampicillin, rifampin, streptomycin, and their combinations were evaluated in vitro against Streptococcus faecalis strain GK and in vivo in rats with an established pyelonephritis resulting from challenge with this same enterococcus. In vitro synergy was demonstrated between all combinations. Comparison of the log colony-forming units of S.