The Thermostability of Staphylococcus Toxins *

Attempts to resolve the question of the identity or non-identity of the so-called staphylococcus toxins have made use of tests of thermostability, without, however, leading to any general agreement as to the heat-resistance of any of the particular toxic fractions. Nor have these tests revealed the essential nature of the substances concerned in the different manifestations of toxic action. The so-called alpha-lysin appears to have been the toxin most extensively studied, with results wholly discordant. Seemingly, this can only mean either that the alpha-lysin has no fixed properties or that in the differences found the strain of origin and the method of cultivation are deternmining factors, in other words, that whether the lysin which acts on rabbit erythrocytes is highly sensitive to heat or is relatively resistant to heat is a matter regulated by the strain producing and the conditions surrounding production of that particular lysin. With this, of course, is coupled the fact that tests with such lysins are always made with materials in which the lysin is admixed with many complex substances derived from the medium, elaborated by the staphylococci in their metabolism, or yielded by dissolution of the organisms. Nothing would be gained by reviewing all reported data; only four of the more recent papers will be mentioned, the first by Rigdon.7 This author reports on the testing of alpha-lysin for heatsusceptibility by exposing the toxin for periods varying from 10 to 120 minutes at temperatures varying between 45 and 570 C. He found that the lability was very great, the larger part of the lysin destruction taking place within the first 30 minutes of heating. To cite but two of his figures: at 520 about 46 per cent of the toxin was destroyed within the half-hour period, at 530 about 83 per cent had been lost. Rigdon adds the interesting comment that the rate of detoxication suggests that the toxin may contain two hemolytic agents, both active on rabbit cells, which differ in stability. His tabulated data support this view. Although Smith and Price8 worked primarily with the beta-lysin, which they say is more resistant to heat than is the alpha-lysin, they