The influence of temperature and humidity on spore formation and germination inBacillus anthracis

Abstract

Experiments performed on spore formation inB. anthracis, in a wide range of closed atmospheres of chemically controlled humidity, showed that the sporing time ofB. anthracisis prolonged considerably as the humidity decreases, both at 26 and 37° C. The effect is less noticeable at the lower temperature.Experiments performed on spore germination in the same organism showed that a temperature range of 20–44° C. permitted germination of the five strains tested. Above a temperature of 39° C. and below 30° C. germination time lengthened considerably.Experiments performed on the influence of humidity on spore germination, both at 26 and 37° C. showed that no germination could take place at a relative humidity of 80% or below. Germination time was considerably prolonged when the humidity value fell below 100%.This work formed part of a thesis for the degree of M.D. in Bristol University. I wish to thank Dr G. S. Wilson for his advice in preparing this paper.