A mechanistic study of the antibacterial effect of silver ions onEscherichia coli andStaphylococcus aureus

✍ Scribed by Feng, Q. L. ;Wu, J. ;Chen, G. Q. ;Cui, F. Z. ;Kim, T. N. ;Kim, J. O.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 781 KB
• Volume: 52
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/1097-4636(20001215)52:4<662::aid-jbm10>3.0.co;2-3

✦ Synopsis

To investigate the mechanism of inhibition of silver ions on microorganisms, two strains of bacteria, namely Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), were treated with AgNO 3 and studied using combined electron microscopy and X-ray microanalysis. Similar morphological changes occurred in both E. coli and S. aureus cells after Ag + treatment. The cytoplasm membrane detached from the cell wall. A remarkable electron-light region appeared in the center of the cells, which contained condensed deoxyribonucleic acid (DNA) molecules. There are many small electron-dense granules either surrounding the cell wall or depositing inside the cells. The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag + treatment. The slighter morphological changes of S. aureus compared with E. coli recommended a defense system of S. aureus against the inhibitory effects of Ag + ions.