In vitro studies showed that
ristomycin was the most active against actinomycetes causing
actinomycosis as compared to
benzylpenicillin,
ampicillin,
methicillin and
lincomycin. The growth of the test microbes was inhibited by
ristomycin in concentrations of 61--122 mg/ml. Since
ristomycin was the most active against actinomycetes, its levels in the blood, parenchymatous organs,
capsule and
pus of actinomycomas of 5 rabbits infected wtih actino nycosis in the submaxillary area were determined. In the control healthy rabbit, the
ristomycin levels were determined in the blood and organs.
Ristomycin was administered intravenously in a single dose of 7000 mg/kg. Its concentrations in the animals were determined in 2.5 hours. The results of the experiments showed that
ristomycin penetrated in therapeutic concentrations into the connective tissue
capsule of actinomycoma. As for the other
antibiotics tested earlier, they failed to penetrate this barrier. In 3 infected rabbits,
ristomycin penetrated even the
pus contained in actinomycoma.
Ristomycin provides therapeutic concentrations in the disease focus and may produce a satisfactory
therapeutic effect in treatment of
actinomycosis.