A strain, Streptomyces No. 7548, was isolated in 1954 from a sample of soil collected in Mishima, Osaka Prefecture. The antibiotic produced by the strain was active chiefly against Gram-positive bacteria, and though extracted as a chemically acid substance, it showed strong activity in basic conditions, and th erefore it was assumed to be a physiologically basic substance. At that time, chlortetracycline, luteomycin and the like were known as physiologically acid substances having acid or amphoteric nature, but as there was found no report on physiologically basic antibiotics, the peculiar properties of the present antibiotic invited the authors’ interest. Thereafter investigation was made on the mycological properties and cultural conditions of the strain and on the extraction and purification of the antibiotic. And from its physiological and physicochemical properties, the antibiotic was assumed to be different from any of known antibiotics, so it was named glumamycin¹⁾.

In the course of systematic screening for new antibiotics, a strain of Streptomyces was isolated, which in submerged culture, produces a new antibiotic, glebomycin, belonging to streptomycin class. The antimicrobial activity of this antibiotic is characteristic of that of streptomycin: Streptomycin-dependent E. coli grows well around a paper disc containing glebomycin, and complete cross-resistance is observed between glebomycin and streptomycin or dihydrostreptomycin on a resistant strain of E. coli. Cysteine does not affect the antibacterial activity of glebomycin. The color reaction of Sakaguchi for the guanidyl radical is positive, but glebomycin does not form maltol on alkaline hydrolysis. The antibiotic was differentiated from other streptomycin-group antibiotics by paper chromatography and other physicochemical and biological properties. One of the significant characteristics of this antibiotic is its extremely low toxicity. This paper deals with the production and biological properties of glebomycin. The isolation and physicochemical properties of the antibiotic²⁾ and the taxonomic studies of the producing strain¹⁾ will be reported in companion papers.

A new antimicrobial agent, glebomycin, has been isolated from fermentation beers of Streptomyces strain No. 12096. Various biological properties of the antibiotic and mycological properties of the producing strain have been described by Okanishi et al,¹⁾ and Ohmori et al.²⁾ The antibiotic was found to belong to the streptomycin-group of antibiotics from the biological and chemical studies.

This paper deals with the isolation, purification and physicochemical properties of glebomycin. Paper chromatographic comparisons with related antibiotics of the streptomycin group are also described.

In the course of searching for new antibiotics, a strain, Streptomyces was isolated which was found to produce a new antibiotic, glebomycin. As reported in the previous papers^1,2) this antibiotic belongs to streptomycin group.

This paper deals with the morphological and cultural characteristics of strain No. 12096 as well as with a comparison of related strains.

Mikamycin belongs to the group of PA 114, streptogramin, staphylomycin and ostreogrycin. It is successfully applied for clinical uses. It is highly effective against gram-positive organisms in vivo as well as in vitro, in spite of the low levels in blood and tissues observed by antimicrobial activity.^1,2,3) The samples obtained before establishment of differential assay⁴⁾ of A and B were not well characterized and showed lower potency particularly in vivo than those obtained later.²⁾ These results bothered us and led us to further biological investigations of mikamycin. Influence of blood on activity of mikamycin, the activity observed by slide cell culture method and mouse protection tests against experimental infections by oral administration were investigated and the results are presented in this paper.

Mikamycin, an antibiotic effective against gram-positive organisms including resistant staphylococci, exhibits a marked activity against experimental infections of staphylococci, hemolytic streptococci and pneumococci.^1,2,3) It has been applied for clinical uses by a number of investigators and successful results have been accumulated. However there remains a discrepancy between a high in vivo activity and a low level in blood and tissues demonstrated by antimicrobial activity.^1~4) For the purpose of investigating this problem, mikamycins A and B were labeled with tritium; and the blood concentration, tissue distribution, and renal and biliary excretion were observed. The results are presented in this paper.

Recently, in the fields of dermatology and surgery, there is a remarkable tendency to delay healing of several infectious dermotoses and post-operative wound-infections, especially caused by staphylococci, inspite of the use of chemotherapeutic agents. This tendency seems to be enhancing gradually and more significant in the staphylococcal infections occurred in the hospital, i. e. so called intrahospital infections^10,11).

In 1959, we reported some results concerning drug-resistance of staphylococci isolated from various infected dermotoses and in the air of our clinic. In that report, we pointed out moderately high ratio (20 %) of pathogenic (coagulase positive) staphylococci in whole staphylococci isolated from the air in our clinic. Regarding the roll of air as the route of hospital infections, the latest studies^3~8,12~14) show that air containing various bacteria could be one of the routes of infections. The purpose of the present paper is to report the summarized results of our experiments concerning staphylococci in our clinic, especially air-borne staphylococci, in the period from May 1959 to April 1960. This paper is primarily concerned with next experiments: (1) to observe variation of the amount of floating staphylococci in the air of our clinic. (2) to observe the ratios of phthogenic strains and of drugs-resistant strains in the following groups of staphylococci isolated in our clinic, the group isolated from infected regions of in-patients, the group isolated from healthy skin of hospital-staffs, the group isolated from the air in our clinic and the group isolated from infected regions of out-patients.

Recently, Ochiaa et al.¹⁾ and Akiba et al.²⁾ found a remarkable phenomenon that multiple drug resistance (resistances to streptomycin, chloramphenicol, tetracycline and sulfonamide) of Shigella can be transferred, as a one-step event, into Escherichia coli by a conjugation process and vice versa. This finding was confirmed by Watanabe and Fukasawa³⁾, Mitsuhashi et al.⁴⁾ and Nakaya et al.⁵⁾ and it was suggested that the transfer is mediated by an episome.³⁾ In connection to this phenomenon, Mitsuhashi et al.⁶⁾ found a frequent co-existence of multi-resistant E. coli in patients bearing multi-resistant Shigella. The multi-resistant E. coli strains could be found at a relatively high rate in tuberculous patients who were administered with streptomycin, isoniazid and PAS (p-aminosalicylate). This report led the present writer to work as to whether the presence of PAS with chloramphenicol in intestine might cause a relatively rapid development o: chloramphenicol resistance by E. coli. This possibility was examined in in vitro experiments.