According to Umezawa, et al.¹⁾, kanamycin is a basic and water-soluble antibiotic produced by Streptomyces kanamyceticus which was isolated from the soil in Nagano Prefecture in Japan. Kanamycin sulfate used in clinical tests is water-soluble white crystalline powder. It is very stable substance which does not decompose by heating at 100°C for 30 minutes in water solution, and does not change its potency for 1 year at 37°C. The molecular formula of kanamycin sulfate is C₁₈H₃₆N₄O₁₁ · H₂SO₄ · H₂O. It was reported that kanamycin is a glucoside consisted of 2 kinds of amino-glucose and desoxystreptamine²⁾. In the kanamycin filtrate, there is a little amount of an effective substance which is separated by paper chromatography. This effective substance includes in its chemical structure an amino-pentose instead of an amino-glucose. This is called kanamycin B. Kanamycin B has antibacterial activity, about one fifth of kanamycin to tubercle bacilli and about 4 times of kanamycin to staphylococci. It shows different side effects, but the products today include too little amount of it to be a trouble.

Kanamycin has wide antibacterial spectrum in vitro, as shown by Umezawa, et al.^1,4,5) and Gourevitch, et al.³⁾ It is effective against most of the pathogenic bacteria as Staphylococci, Klebsiella pneumoniae, Diplococcus pneumoniae, Cl. diphtheriae, B. anthracis, E. coli, S. typhi, S. paratyphi, S. dysentheriae, Brucella, etc. (minimum inhibitory concentrations less than 5 mcg/ml, at pH 7. 2) , and also against tubercle bacilli at about 2~5 mcg/ml. However, it is not so effective against some strains of Streptococcus hemolyticus, Proteus and Pseudomonas aeruginosa, is ineffective against Candida and Aspergillus, and also against virus. Kitaoka, et al.⁶⁾ reported that kanamycin is effective also against Borrelia, Treponema and Leptospira. As for the antibiotic resistance, it is noticeable that, as will be described later, the resistance of E. coli or Staphylococci to kanamycin is acquired very slowly and in low degree. Kanamycin does not show a cross resistance with other known antibiotics.

When kanamycin is injected intramuscularly, it is absorbed rapidly into the blood and found in kidney, liver, lung, spleen, urine and bile considerably in high concentrations, as pointed out by Takeuchi, et al.⁴⁾ Ichikawa, et al.⁷⁾ found that kanamycin is excreted in urine in high concentration. As kanamycin is not absorbed when administered orally, it is expected to use for infections of intestines and for preoperative procedure of digestive tracts.

The present authors carried out the clinical experiments mainly on surgical infections. The results are described in this paper.