Two antibiotics (lavendulin and actinorubin) produced by Actinomyces; isolation and characteristics of the organisms.

Two strains of Actinomyces showing antibacterial properties of specialinterest were isolated from greenhouse soil during a search for antibiotics effective agaist gram-negative and acid-fast microorganisms. One strain, designated as A-10, appears to be a variant of Actinomyces lavenduke. Although a similarity to streptothricin (Waksman, 1945) was noted in the spectrum obtained from limited antibacterial tests in which the unpurified product of A-10 was used, the culture differed so much in appearance, nutritional requirements, and other respects ;from A. lavendulae, a known producer of streptothricin, as to merit further study. More extensive antibacterial tests, performed later with the purified antibiotie, showed it to be distinct from streptothricin. We have named it lavenduin. The second strain of Actinomyces was found to produce an antibacterial substance resmbling streptothriein and streptomycin but distinct from either :of these. This strain of Actinomyces, designated as A-105, resembles in some respects Actinomyces erythres, A. fradii, A. albosporeus, and A. californicus without being unmistakably one, or a variant of any, of these species. We -have named the antibiotic produced by strain A-105 actinorubin because of the characteristic red mycelium which the organism forms on many media. This paper describes the methods by which the strains of Actinomyces were isolated, their cultural characteristics, the cultural conditions which were observed to yield maximum production of the antibiotic substances, and their antibacterial properties in vitro. The methods for the chemical puriflcitioti of lavendulin and actinorubin will be described elsewhere by Junowicz-Kocholaty and Kocholaty. The chemotherapeutic studies on lavendulin and actinorubin will be published by one of us (Morton, 1947). Method8 used in isolating from nature organims which inhibit bacteria. The methods used for isolating and testing A-10, A-105, and A-82, the latter an organism producing an antismegmatis-factor (Kelner and Morton, 1946), were similar. Our procedures were adapted from those described by-WAkman', Bugie, and Schatz (1944) and in general resembled those described by Emerso* et al. (1946). The actinomycetes were isolated from greenhouse soil (a rich and convenient source) by plating the soil in nutrient agar and selecting colonies