Electron microscopic study of the cell surface of dibekacin-treated Pseudomonas aeruginosa

Electron microscopy of thin sections of Pseudomonas aeruginosa IAM 1007 treated with dibekacin revealed blebs, disintegration of the outer membrane of the cell wall and degenerative features of the cytoplasm. In the next experiment, the cell wall fraction was isolated from the mechanically disrupted cells, incubated with dibekacin and was subjected to electron microscopy, in order to find a clue to the action mechanism of dibekacin on the cell wall of Pseudomonas aeruginosa IAM 1007. As a result, it was found that unidentified substances were released from the surface of the cell wall and that the outer membrane of the cell wall disappeared. The degree of changes of the cell wall ultrastructure was almost proportional to the length of incubation with dibekacin. These findings strongly suggest that dibekacin directly disintegrates the outer membrane of the cell wall of Pseudomonas aeruginosa IAM 1007.