Emergence and development of resistance to antimicrobial chemicals and heat in spores ofBacillus subtilis

摘要

The emergence and development of chemical and thermal resistance in spores ofBacillus subtiliswas examined. The chemicals studied were of the disinfectant type: glutaraldehyde, hypochlorite, hypochlorite‐methanol and povidone‐iodine. Growth and sporulation were followed by electron microscopy and resistance assigned to specific stages in relation to45Ca and DPA accumulation. A sequential development of resistance was observed with thermal resistance appearing first at early Stage V corresponding to maturation of cortex and deposition of rudimentary spore coat material. Chemical resistance coincided with middle to late Stage V dependent on the chemical concerned. A progressive development of resistance was observed on prolonged incubation in sporulation medium and was affected by inclusion of lysozyme in the spore washing seque