Until recently, Greig test has been used as the most important method of differentiation between Vibrio cholerae and Vibrio eltor. In these several years, however, it has become difficult to depend only on this method for the differentiation of these two groups, since there has been found many strains of V. eltor which are negative in soluble hemolysine test1). Therefore, several other methods have been reported by various workers for the rapid differentiation of both groups, one of those is the difference of sensitivity against polymyxin B (PX-B)2). It was found by the authors that the same difference of sensitivity is also observed with colistin (CL), an antibiotic closely related to PX-B3), and we have devised a disk method using disk which contains a proper amount of CL. This report is chiefly concerned with the experimental conditions of the test method.
An extensive study on the behaviour of some penicillin-producing organisms in prefence of various organic compounds of different structural categories is now in progress. Among the compounds tried toluene is of particular interest. Its existence in the metabolic fluids of submerged cultures of P. chrysogenum suppressed the formation of penicillin. Meanwhile, the metabolism solutions exhibited a marked inhibitory influence against the growth of Escherichia coli while no antimicrobial effect against B. subtilis was observed. This attracted the attention of the authors to the possible existence of a gram negative antibiotic in the culture fluids supplemented with toluene. The results of Farvhashi et al1). are not in line with the present findings. They found that the addition of toluene depressed the mycelial growth with a simultaneous increase in the yields of penicillin.
The work described in the present paper concerns the fermentation procedure, isolation technique and investigations on the properties of the antibiotic.
Since leucomycin (LM), an antibiotic produced by Streptomyces kitasatoensis, was reported by Hata et al.1) in 1953, a number of papers have been published on its producing organism2,4), physicochemical properties8, 9, 10), antibiotic spectrum13, 14), concentrations in serum and tissues5) therapeutic effect in experimental infections in animal6, 8) etc. The further studies7, 11) revealed that LM consists of 6 components named LM-A1, A2, B1, B2, B3 and B4, and that LM-A1 is main component which has the strongest antibiotic activity9, 12). Therefore, it is inevitable that the experimental results in the past varied more or less with the ratio of these components contained in the lots of LM-complex used in the experiments. The present paper deals with the potency of LM-A1, medium for the assay, the antibiotic spectrum, and the sensitivities of staphylococci isolated from patients. Erythromycin (EM) was used as a control.
As reported in the previous paper, leucomycin A1 (LM-A1) has a high potency that corresponds to 130% of leucomycin complex (LM-complex). Experiments were carried out on blood and tissue levels and acute toxicity of LM-A1, using erythromycin (EM) as a control as same as the previous paper.
As reported in the previous paper1, 2), leucomycin (leucomycin complex) was proved to be effective on experimental infections in animals caused by microorganisms including Diplococcus pneumoniae, Clostridium welchii, Haemophilis pertussis, Spirochaete recurrentis, Rikettsia prowazeki, R.tsutsugamushi, nonbacterial infectious pneumoma in sheep etc., when leucomycin was administered after the challenges with those organisms. Since then, leucomycin has been applied clinically, and the effect was proved by many authors. Leucomycin tartrate was recognized to have a rapid effect because it is easily soluble in water and is injectable intravenously. In the prolonged treatment of leucomycin, almost no side effect was noticed. 3, 4, 5)
Although the development of resistant strains to various antibiotics, especially that of resistant staphylococcal strains, became a serious problem in recent, relatively a few reports described the resistant strains to leucomycin. The cross-resistance between leucomycin and other macrolide antibiotics was not always recognized remarkably6, 7, 8). It was also reported that leucomycin is more active at acidic side and less active as alkaline side in vitro, in contrast to erythromycin3). The blood levels of leucomycin were proved to be lower than those of erythromycin when the same doses were given, and the assayable levels were maintained also for a shorter time.
Recently leucomycin A1 (LM-A1), the main component of leucomycin (LM), was isolated and found to have stronger in vitro antibacteial activity as compared with leucomycin complex. The toxicity was also found very low. Therefore, the therapeutic effect of leucomycin A1 was examined by the protection tests in animals experimentally infected with Staphylococcus aureus, Streptococcus hemolyticus and Diplococcus pneumoniae. Erythromycin (EM) was used as the control throughout. The present paper deals with the experimental results.
Recently leucomycin A12) was isolated from leucomycin1), an antibiotic produced by Streptomyces kitasatoensis. Leucomycin A1(LM-A1) is a main component of leucomycin (LM), and has the most powerful antibiotic activity. The biological properties of LM-A1 were reported in separate papers. 3, 4, 5) In the present paper are reported the results of experiment in which the activity of LM-A1 was enhanced by the combination with various sulfa drugs.