Scanning electron microscopy images of autoclaved Escherichia coli cells suggest intact cells after treatment

Autoclave treatment is the standard approach for killing microbial cells during decontamination. During this process, the common perception is that autoclaved cells are lysed due to high pressure. However, this may not be true. Preliminary images of autoclaved <i>Escherichia coli</i> DH5α cells under scanning electron microscopy imaging revealed the surprising finding of intact rod-shaped cells. Autoclave conditions were 121 ^oC for 15 minutes. Although the images are not of high quality and are blurry, intact rod-shaped cells were still clearly discernible from the images, especially at high magnification. Such a result suggests that the thin peptidoglycan layer in the <i>E. coli</i> double membrane cell envelope possess surprising amount of strength to withstand elevated pressure during autoclave sterilization. Finally, the result is also suggestive of hitherto unknown structural and design features of the peptidoglycan and cell envelope of <i>E. coli</i> that afford the bacterium increased resistance to high pressure.