Photodynamic inactivation of Staphylococcus aureus using tetraethylene glycol-substituted Zn(II) phthalocyanine

Biotech Histochem. 2021 May;96(4):311-314. doi: 10.1080/10520295.2020.1854855. Epub 2020 Dec 16.

Abstract

Methicillin resistant Staphylococcus aureus infections are increasing, especially in intensive care units. A new method for photodynamic inactivation (PDI) generates reactive oxygen species by photosensitization to kill bacteria. We investigated the PDI effect of tetraethylene glycol-substituted Zn(II) phthalocyanine (TEG-P) on S. aureus strains including two standards (ATCC 25923 and ATCC 43400) and 20 clinically isolated methicillin sensitive and 20 methicillin resistance strains. We also investigated three treated groups: 650 nm laser only, TEG-P only and TEG-P + laser, plus one control group. Treatments included 0.5, 1, 2, 4, 8, 16, 32 µg/ml concentrations of TEG-P. No suppression of bacterial growth was observed in the control, laser only and TEG-P only groups whether or not S. aureus was methicillin resistant. Bacterial growth was suppressed by 85% using 8 µg/ml TEG-P and completely suppressed by 32 µg/ml TEG-P in the TEG-P + laser group. A combination of TEG-P + laser treatment may be an alternative to conventional antibiotics for routine treatment of S. aureus infections, although further investigation of the effect at the tissue level is required.

Keywords: Photodynamic inactivation; Staphylococcus aureus; phthalocyanine; tetraethylene glycol-substituted Zn(II) phthalocyanine.

MeSH terms

  • Anti-Bacterial Agents
  • Humans
  • Indoles
  • Photosensitizing Agents
  • Polyethylene Glycols
  • Staphylococcal Infections
  • Staphylococcus aureus*
  • Zinc

Substances

  • Anti-Bacterial Agents
  • Indoles
  • Photosensitizing Agents
  • Polyethylene Glycols
  • Zinc
  • tetraethylene glycol
  • phthalocyanine