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Bactericidal effect of photodynamic inactivation against methicillin-resistant and methicillin-susceptible

Mariusz Grinholc1, Bozena Szramka, Julianna Kurlenda

  • 1Department of Biotechnology, Division of Molecular Diagnostics, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822 Gdansk, Poland. grinholc@biotech.ug.gda.pl

Journal of Photochemistry and Photobiology. B, Biology
|December 21, 2007
PubMed

Insights

Photodynamic inactivation (PDI) shows potential as an alternative therapy against Staphylococcus aureus. This study found PDI effectiveness varied by bacterial strain, with biofilm production potentially influencing outcomes.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Photomedicine

Background:

  • Staphylococcus aureus is a significant cause of hospital-acquired infections, leading to severe conditions like sepsis and toxic-shock syndrome.
  • Antibiotic resistance in S. aureus presents major therapeutic challenges, necessitating alternative treatment strategies.
  • Photodynamic inactivation (PDI) is emerging as a promising alternative to conventional antibiotic therapy.

Purpose of the Study:

  • To evaluate the bactericidal efficacy of photodynamic inactivation (PDI) against clinical isolates of methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus.
  • To investigate the influence of bacterial strain characteristics, such as biofilm production, on PDI treatment outcomes.

Main Methods:

  • Photodynamic inactivation was performed using protoporphyrin diarginate as a photosensitizer.
  • The study analyzed the PDI effect on 40 clinical MRSA and 40 MSSA strains isolated from hospitalized patients.
  • An ATCC strain (25904) was used as a reference control.

Main Results:

  • Photodynamic inactivation demonstrated a strain-dependent bactericidal effect, with reductions in viable bacterial counts ranging from 0 to 3 log(10) units.
  • A correlation was observed between the ability of S. aureus strains to produce biofilm and their varied responses to PDI.
  • The precise mechanism underlying the observed strain-dependent efficacy of PDI remains to be elucidated.

Conclusions:

  • Photodynamic inactivation is a potential therapeutic approach for treating infections caused by both MRSA and MSSA strains.
  • Bacterial biofilm production may play a role in modulating the effectiveness of PDI against Staphylococcus aureus.
  • Further research is warranted to understand the mechanisms of PDI and optimize its application against S. aureus infections.

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