ON THE DIFFERENTIATION OF STREPTOMYCIN AND ALLIED SUBSTANCES (STREPTOTHRICIN GROUP) AND RAPID ISOLATION OF STREPTOMYCIN-PRODUCING STRAIN (1948)

Since we undertook the studies on streptomycin, various kinds of actinomyces producing substances resembling streptomycin were isolated (1, 2), and we were thrown into confusion, as to which one of them was streptomycin. The difficulties of the isolation of streptomycin-producing strain seem to be ascribable to the existence of many kinds of actinomyces producing other substances resembling streptomycin. which, in the broth, inhibit B. coli and other gram negative bacteria rather more strongly than streptomycin.Streptomycin, streptothricin (3) and allied substances are usually differentiated on the basis of their antibacterial spectra, but this differentiation method can only be utilized in laboratories, where streptomycin, streptothricin and other related substances are already isolated, since even among the same species the resistance of bacteria may be different in different individual strains.Recently Waksman, Reilly, ahd Jonstone (4) reported that streptomycin-producing strain was much more resistant against streptomycin and the incorporation of streptomycin in the isolating medium in concentration sufficient to inhibit the growth of the usual actinomyces facilitated the isolation of streptomycin strain. Among 120 antibiotic strains of various kinds of actinomyces isolated by us, 21 strains grew on the nutrient agar plus 50 μg of streptomycin hydrochloride (Merck's sample, about 600 μ/mg) and from one of them streptomycin was extracted and purified as its reineckate crystal. This and other strains producing related substances and the antibiotic substances extracted from them were comparatively studied, and it was concluded that among these substances streptomycin was particular in respect of the tolerance of streptomycin-fast bacteria and the colour of its Sakaguchi's reaction, though they were all similar in extractability and solubility, and inhibited both gram positive and negative bacteria.Now we should like to devide the antibiotic substances resembling, streptomycin and streptothricin into streptomycin and streptothricin-group substances, among the latter streptothricin having been first isolated by Waksman and others (3) . Lavendulin and actinorubin found by Kelner and Morton (5) and basic antibiotic substances resembling a streptomycin and streptothricin reported by us (1, 2) are to be included in streptothricin-group substances, for the streptothricin-fast B. coil is nearly as susceptible to these substances as the normal culture. Streptin found by Foster and others (6) also seems to belong to the streptothricin-group substances, for it is extracted in the same way as streptomycin from the broth of A, reticulus-ruber, which was found by us to produce a streptothricin group: substances and a streptomycin-producing strain is not yet found in species other than S. griseus.On account of the possible differentiation of streptomycin from allied substances and also of the important discovery by Waksman and others (4), showing the specific tolerance of streptomycin-producing strain against streptomycin, the isolation of the streptomycin strain became much easier.In the present paper method for the differentiation of streptomycin and strepthothricin-graup substances and the rapid isolation and identification of streptomycin-producing strain are described.