- 一般社団法人 国立医療学会
- 医療 (ISSN:00211699)
- vol.14, no.2, pp.98-102, 1960 (Released:2011-10-19)
In contrast with Ethanol (BA) the bactericidal action of Isopropanol (IPA) to the various organisms, with which we are most frequently contaminated, as investigated. The obtained results are as follows:1) According to the species of organisms the concentration of IPA for bactericidal action differ. The highest degree of the concentration was required toward Micrococcus pyogenes var, aureus. However, the IPA was unable to destroy spore-bearing organism such as Bacillus subtilis.2) As for bactericidal effects for Micrococcus pyogenes var. aureus, 30% concentrated IPA corresponds to 50% concentrated EA. The 25% concentrated IPA and the 40% concentrated EA were equal toward Shigella flexrneri, Proteus vulgaris, Escherichia coli, Aerobacter aerogenes, Alcaligenes faecalis and Pseudomonas aeruginosa, Judging from these various kinds of concentrations the bactericidal activity on IPA was about 1.6 times as strong as that of EA.3) When the IPA concentration increases, its bactericidal effect does not decrease and 99% concentrated IPA destroys Salm. typhi and Micrococcus pyogenes var. aureus within 20 seconds. This to me, that different from BA, the bactericidal effect of IPA increases steadily as concentration approaches to 100%.4) The 35% concentrated IPA is enough to kill Salm. typhi within 20 seconds, while the 45% concentration is enough to kill Micrococcus pyogenes var. aureus within the same time. Consequently, it is deemed that the 45% IPA solution is able to be employed as a substitute on the 70% EA solution for the purpose of surgical disinfection and antiseptic.5) Against Bac, subtilis, IPA is not as powerful as EA, even with increasing concentrated solution. This fact reveals to me that IPA should not be relied upon to destroy pathogenic spore-bearing organisms such as Clostridium tetani, Clostridium welchii and Bacillus anthracis.6) Through broth culture test, it is described that between pH 6.4 and pH 8.6 there is no different bactericidal effect on IPA solution. However, in the event of coexistence of plasma protein, pH 6.4 gives rise to the prolongation of bactericidal time, and if the pH is regulated to 8.6 the bactericidal action results in normal way.Judging from these results, so far as the disinfection is concerned, it is economical to use IPA as a replacement of EA as IPA is not only inexpensive but it is about 1.6 times as powerful as EA. The IPA should be used in 45% concentration by volume.