The Absorption of Polymyxin E by Bacteria and Bacterial Cell Walls and its Bactericidal Action

作者：A.V. Few, Jack Henry Schulman · 发表于：Journal of General Microbiology · 年份：1953 · DOI：10.1099/00221287-9-3-454 · 被引用次数：79 · 研究领域：Antibiotic Resistance in Bacteria、Historical Medical Research and Treatments、Antimicrobial Resistance in Staphylococcus

SUMMARY: Isotherms of the absorption of polymyxin E by Bacillus subtilis, Pseudomonas denitrificans and Streptococcus faecalis after 20 min. contact with the antibiotic were determined. Tested on seven different bacteria, the maximum amounts of polymyxin E absorbed showed that the polymyxin-sensitive bacteria were capable of absorbing much greater quantities of the antibiotic than resistant organisms. When the bacteria were suspended in buffer solutions, the ultraviolet spectra of their supernatant fluids showeda maximum absorption at 260 mμ.; purines and pyrimidines contribute to this maximum. Addition of polymyxin E to suspensions of sensitive bacteria caused an immediate increase in the height of this maximum. Similar treatment of resistant organisms caused very little immediate increase in the amount of 260 mμ. absorbing material released. On prolonged incubation of untreated and polymyxin E treated cells there was a steady increase in the amount of 260 mμ. absorbing cell solutes released into the suspension media. Within the pH range 4·4–7·6 no optimum pH value was found for the polymyxin E absorption process or for the cellular release mechanism. The absorption isotherms of polymyxin E obtained with cell-wall preparations derived from sensitive and resistant bacteria showed that cell walk derived from sensitive organisms bound more polymyxin E than cell-wall preparations from resistant organisms. On treatment of sensitive bacteria with concentrations of polymyxin E less...