Eradication of Propionibacterium acnes by its endogenic porphyrins after illumination with high intensity blue light

Helena Ashkenazi, Zvi Malik, Yoram Harth, Yeshayahu Nitzan

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Abstract

Propionibacterium acnes is a Gram-positive, microaerophilic bacterium that causes skin wounds. It is known to naturally produce high amounts of intracellular porphyrins. The results of the present study confirm that the investigated strain of P. acnes is capable of producing endogenic porphyrins with no need for any trigger molecules. Extracts from growing cultures have demonstrated emission peaks around 612 nm when excited at 405 nm, which are characteristic for porphyrins. Endogenic porphyrins were determined and quantified after their extraction from the bacterial cells by fluorescence intensity and by elution retention time on high-performance liquid chromatography (HPLC). The porphyrins produced by P. acnes are mostly coproporphyrin, as shown by the HPLC elution patterns. Addition of δ-aminolevulinic acid (ALA) enhanced intracellular porphyrin synthesis and higher amounts of coproporphyrin have been found. Eradication of P. acnes by its endogenic porphyrins was examined after illumination with intense blue light at 407-420 nm. The viability of 24 h cultures grown anaerobically in liquid medium was reduced by less than two orders of magnitude when illuminated once with a light dose of 75 J cm-2. Better photodynamic effects were obtained when cultures were illuminated twice or three times consecutively with a light dose of 75 J cm-2 and an interval of 24 h between illuminations. The viability of the culture under these conditions decreased by four orders of magnitude after two illuminations and by five orders of magnitude after three illuminations. When ALA-triggered cultures were illuminated with intense blue light at a light dose of 75 J cm-2 the viability of the treated cultures decreased by seven orders of magnitude. This decrease in viability can occur even after a single exposure of illumination for the indicated light intensity. X-ray microanalysis and transmission electron microscopy revealed structural damages to membranes in the illuminated P. acnes. Illumination of the endogenous coproporphyrin with blue light (407-420 nm) apparently plays a major role in P. acnes photoinactivation. A treatment protocol with a series of several illuminations or illumination after application of ALA may be suitable for curing acne. Treatment by both pathways may overcome the resistance of P. acnes to antibiotic treatment.

Original languageEnglish
Pages (from-to)17-24
Number of pages8
JournalFEMS Immunology and Medical Microbiology
Volume35
Issue number1
DOIs
StatePublished - 21 Jan 2003

Bibliographical note

Funding Information:
The authors wish to thank Curelight Ltd. for the blue light illumination system they provided. They also wish to thank Mrs. R. Dror for her excellent technical assistance and Mrs. L. Warshavsky for operating the HPLC system. This work was supported in part by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanitis (to Y.N.). Additional partial support was given by the Health Sciences Research Center Funds (to Y.N.) and in part by the Rappaport Foundation for Medical Microbiology (to Y.N.).

Funding

The authors wish to thank Curelight Ltd. for the blue light illumination system they provided. They also wish to thank Mrs. R. Dror for her excellent technical assistance and Mrs. L. Warshavsky for operating the HPLC system. This work was supported in part by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanitis (to Y.N.). Additional partial support was given by the Health Sciences Research Center Funds (to Y.N.) and in part by the Rappaport Foundation for Medical Microbiology (to Y.N.).

FundersFunder number
Rappaport Foundation for Medical Microbiology
Israel Academy of Sciences and Humanities
Israel Science Foundation

    Keywords

    • Acne
    • Endogenic porphyrins
    • Illumination by blue light
    • Photoeradication
    • Phototreatment of acne
    • Propionibacterium acnes

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