Sonodynamic action of chlorin e6 on Staphylococcus aureus and Escherichia coli

• Chlorin e6 had sonodynamic antibacterial activity on both gram-positive and negative bacteria.
• Gram-positive bacteria were more sensitive to sonodynamic treatment of chlorin e6 than gram-negative bacteria.
• Sonodynamic action of chlorin e6 might be a promisng alternative to eradicate pathogens.

Bacteria remain a great threat to human health. In the present study, we examined whether sonodynamic action of chlorin e6 had antibacterial activity on gram-positive bacterial strain Staphylococcus aureus (S. aureus) and gram-negative bacterial strain Escherichia coli (E. coli). Colony forming unit (CFU) assay showed that sonodynamic treatment of chlorin e6 induced a 2-log reduction in CFU of E. coli cells, 7-log reduction in CFU of S. aureus. Fluorescent microscopy observed that dead cells remarkably increased whereas live cells decreased after sonodynamic treatment of chlorin e6 on S. aureus cells. We first demonstrated that sonodynamic action of chlorin e6 has antibacterial effect on both gram-positive and negative bacteria, more powerful on gram-positive bacteria.