This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Demidova, T. N.
Right arrow Articles by Hamblin, M. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Demidova, T. N.
Right arrow Articles by Hamblin, M. R.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, June 2005, p. 2329-2335, Vol. 49, No. 6
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.6.2329-2335.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Effect of Cell-Photosensitizer Binding and Cell Density on Microbial Photoinactivation

Tatiana N. Demidova1,2 and Michael R. Hamblin1,3,4*

Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts 02114,1 Department of Molecular, Cellular and Developmental Biology, Tufts University, Boston, Massachusetts 02111,2 Department of Dermatology, Harvard Medical School, Boston, Massachusetts 02115,3 Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 021394

Received 6 July 2004/ Returned for modification 12 January 2005/ Accepted 18 February 2005

Photodynamic therapy involves the use of nontoxic dyes called photosensitizers and visible light to produce reactive oxygen species and cell killing. It is being studied as an alternative method of killing pathogens in localized infections due to the increasing problem of multiantibiotic resistance. Although much has been learned about the mechanisms of microbial killing, there is still uncertainty about whether dyes must bind to and penetrate various classes of microbe in order to produce effective killing after illumination. In this report, we compare the interactions of three antimicrobial photosensitizers: rose bengal (RB), toluidine blue O (TBO), and a poly-L-lysine chlorin(e6) conjugate (pL-ce6) with representative members of three classes of pathogens; Escherichia coli (gram-negative bacteria), Staphylococcus aureus (gram-positive bacteria), Candida albicans (yeast). We compared fluence-dependent cell survival after illumination with the appropriate wavelengths of light before and after extracellular dye had been washed out and used three 10-fold dilutions of cell concentration. pL-ce6 was overall the most powerful photosensitizer, was equally effective with and without washing, and showed a strong dependence on cell concentration. TBO was less effective in all cases after washing, and the dependence on cell concentration was less pronounced. RB was ineffective after washing (except for S. aureus) but still showed a dependence on cell concentration. The overall order of susceptibility was S. aureus > E. coli > C. albicans, but C. albicans cells were 10 to 50 times bigger than the bacteria. We conclude that the number and mass of the cells compete both for available dye binding and for extracellularly generated reactive oxygen species.

* Corresponding author. Mailing address: Massachusetts General Hospital, BAR314B, 40 Blossom Street, Boston, MA 02114-2698. Phone: (617) 726-6182. Fax: (617) 726-8566. E-mail: hamblin{at}helix.mgh.harvard.edu.

Antimicrobial Agents and Chemotherapy, June 2005, p. 2329-2335, Vol. 49, No. 6
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.6.2329-2335.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Wu, J., Xu, H., Tang, W., Kopelman, R., Philbert, M. A., Xi, C. (2009). Eradication of Bacteria in Suspension and Biofilms Using Methylene Blue-Loaded Dynamic Nanoplatforms. Antimicrob. Agents Chemother. 53: 3042-3048 [Abstract] [Full Text]  
  • Sharma, M., Visai, L., Bragheri, F., Cristiani, I., Gupta, P. K., Speziale, P. (2008). Toluidine Blue-Mediated Photodynamic Effects on Staphylococcal Biofilms. Antimicrob. Agents Chemother. 52: 299-305 [Abstract] [Full Text]  
  • Konopka, K., Goslinski, T. (2007). Photodynamic Therapy in Dentistry. JDR 86: 694-707 [Abstract] [Full Text]  
  • Fuchs, B. B., Tegos, G. P., Hamblin, M. R., Mylonakis, E. (2007). Susceptibility of Cryptococcus neoformans to Photodynamic Inactivation Is Associated with Cell Wall Integrity. Antimicrob. Agents Chemother. 51: 2929-2936 [Abstract] [Full Text]  
  • O'Riordan, K., Sharlin, D. S., Gross, J., Chang, S., Errabelli, D., Akilov, O. E., Kosaka, S., Nau, G. J., Hasan, T. (2006). Photoinactivation of Mycobacteria In Vitro and in a New Murine Model of Localized Mycobacterium bovis BCG-Induced Granulomatous Infection.. Antimicrob. Agents Chemother. 50: 1828-1834 [Abstract] [Full Text]  
  • Tegos, G. P., Anbe, M., Yang, C., Demidova, T. N., Satti, M., Mroz, P., Janjua, S., Gad, F., Hamblin, M. R. (2006). Protease-Stable Polycationic Photosensitizer Conjugates between Polyethyleneimine and Chlorin(e6) for Broad-Spectrum Antimicrobial Photoinactivation.. Antimicrob. Agents Chemother. 50: 1402-1410 [Abstract] [Full Text]  
  • Tegos, G. P., Hamblin, M. R. (2006). Phenothiazinium Antimicrobial Photosensitizers Are Substrates of Bacterial Multidrug Resistance Pumps. Antimicrob. Agents Chemother. 50: 196-203 [Abstract] [Full Text]  
  • Demidova, T. N., Hamblin, M. R. (2005). Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes. Appl. Environ. Microbiol. 71: 6918-6925 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»