ULTRASTRUCTURE OF THE INNER SPORE COAT OF BACILLUS-STEAROTHERMOPHILUS

The very high resistance of Bacillus stearothermophilus spores to chem ical and physical agents, confers on this bacterium a long survival in the environment. In this study, the morphological characteristics of three culture collection strains of B. stearothermophilus spores were investigated by transmission electron microscopy, showing the essentia l ultrastructure of the inner spore coat. The multilaminar structure a ppeared as alternating 2 nm electron dense and 3 nm electron transpare nt layers, with up to fifteen dense layers in the ATCC 7953 strain.