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The bacterial flora of the skin surface following routine MAL-PDT

Lars Eeik Bryld1, Gregor B E Jemec

  • 1Department of Dermatology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark.

The Journal of Dermatological Treatment
|September 15, 2006
PubMed

Insights

Methylated 5-aminolevulinate photodynamic therapy (MAL-PDT) does not significantly alter skin bacterial flora in patients. This suggests its benefits for non-neoplastic skin conditions are unlikely due to antibacterial effects.

Area of Science:

  • Dermatology
  • Photomedicine
  • Microbiology

Background:

  • Photodynamic therapy with methylated 5-aminolevulinate (MAL-PDT) shows promise for non-neoplastic skin diseases like acne and rosacea.
  • Previous suggestions indicated a potential antibiotic effect of PDT, but concerns exist regarding immunosuppression and barrier defects post-treatment.
  • Differentiating PDT-induced skin damage from secondary bacterial infection can be challenging for non-dermatologists.

Purpose of the Study:

  • To investigate the impact of MAL-PDT on the skin's bacterial flora.
  • To determine if changes in bacterial composition or density occur following MAL-PDT.
  • To assess the role of antibacterial effects in MAL-PDT's efficacy for non-neoplastic skin conditions.

Main Methods:

  • A study involving 47 patients undergoing MAL-PDT treatment.
  • Collection of skin swabs immediately before MAL application and directly after light irradiation.
  • Analysis of bacterial growth, species identification, and density.

Main Results:

  • Bacterial growth was observed in 18 out of 47 patients.
  • No statistically significant changes were detected in specific bacterial species or surface bacterial density.
  • The study found no clinically significant alterations in the skin's bacterial flora due to routine MAL-PDT.

Conclusions:

  • Routine MAL-PDT does not appear to significantly affect the skin's bacterial flora.
  • The observed therapeutic effects of MAL-PDT on non-neoplastic skin diseases are likely not mediated by a direct antibacterial mechanism.
  • Further research may be needed to elucidate the precise mechanisms behind MAL-PDT's efficacy.

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