Electron Microscopy of Staphylococcus aureus Treated with Tetracycline.

After exposure to tetracycline, Staphylococcus aureus was fixed with formaldehyde and osmium tetroxide, thin-sectioned, and examined with the electron microscope. Compared with control cells, the tetracycline-treated cells had no transvers septa, were larger, had a greater electron density, and had thicker cell walls.