Studies on the in vitro Antibacterial Activity of Leucomycin

Abstract

Several workers^1–6) have reported that leucomycin, an antibiotic isolated by Hata and his colleagues^7–11) in 1953 from a culture filtrate of Streptomyces kitasatoensis Hata, has a broad antibacterial spectrum which includes gram-positive and some gram-negative bacteria, spirochaetes, rickettsiae and some larger viruses. Leucomycin also exhibits a clinical efficacy for various kinds of infectious diseases caused by those microorganisms. Recently, Abe and others¹²⁾ demonstrated that leucomycin is a mixture composed of at least six biologically active components, A₁, A₂, B₁, B₂, B₃ and B₄, which were separated by paper chromatographic and electrophoretic methods. The fraction A₁ ranked first in antimicrobial activity.

In view of the scarcity of fundamental and systematic data on in vitro antibacterial activity of leucomycin, the authors examined this agent, especially the A₁ fraction, in respect to the antibacterial activity against a variety of pathogenic bacteria, especially erythromycin-resistant staphylococci. The influence of a change in pH of a culture medium and the addition of whole blood or its components to a medium on the antibacterial activity of leucomycin and A₁ fraction were also investigated.

The results obtained from these studies were compared with activities of similar antibiotics, erythromycin and oleandomycin.