Previous Article | Next Article 
Antimicrobial Agents and Chemotherapy, April 2008, p. 1366-1373, Vol. 52, No. 4
0066-4804/08/$08.00+0 doi:10.1128/AAC.01372-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.
Effects on Gram-Negative and Gram-Positive Bacteria Mediated by 5-Aminolevulinic Acid and 5-Aminolevulinic Acid Derivatives
Nicolas Fotinos,1
Maruska Convert,2,
Jean-Claude Piffaretti,2,
Robert Gurny,1 and
Norbert Lange1*
Department of Pharmaceutics and Biopharmaceutics, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 30 Quai Ernest Ansermet, Geneva 1211, Switzerland,1 Institute of Microbiology, Via Mirasole 22A, Bellinzona 6500, Switzerland2
Received 24 October 2007/ Returned for modification 27 November 2007/ Accepted 2 January 2008
Due mainly to the extensive use of antibiotics, the spread of multiresistant bacterial strains is one of the most worrying threats to public health. One strategy that can be used to overcome potential shortcomings might be the inactivation of these microorganisms by 5-aminolevulinic acid (5-ALA) or 5-ALA derivative-mediated photodynamic therapy (PDT). 5-ALA has no photoactive properties, but when it is given exogenously, it acts as a precursor of photosensitive porphyrins predominantly in tissues or organisms that are characterized by a high metabolic turnover, such as tumors, macrophages, and bacteria. However, the weak ability of 5-ALA to cross biological barriers has led to the introduction of more lipophilic derivatives, such as methyl aminolevulinate or hexyl aminolevulinate, which display improved capacities to reach the cytoplasm. Starting from the hypothesis that more lipophilic compounds carrying only a permanent positive charge under physiological conditions may more easily cross the bacterial multilayer barrier, we have tested the efficacies of some 5-ALA n-alkyl esters for the inactivation of bacteria. For this purpose, different bacterial strains were incubated with 5-ALA or its corresponding esters of different lipophilicities. Then, the bacteria were irradiated with light and the numbers of CFU post-PDT were counted and compared to those for the controls, which were kept in the dark. Furthermore, the total amount of accumulated porphyrins was quantified by high-pressure liquid chromatography analysis. In our studies, analysis of the bacterial extracts revealed the presence of all the porphyrins involved in heme biosynthesis, from uroporphyrin to protoporphyin IX. The efficacy of bacterial inactivation was a function of the total amount of porphyrins produced, independently of their nature. The 5-ALA methyl and butyl esters were the most effective compounds with respect to the photodynamic inactivation of bacteria. We observed significant differences in terms of the optimal drug concentration, bactericidal activities, and porphyrin production.
* Corresponding author. Mailing address: Department of Pharmaceutics and Biopharmaceutics, School of Pharmaceutical Sciences, University of Geneva, Quai Ernest Ansermet 30, Geneva 1211, Switzerland. Phone: (41) 22 379 33 35. Fax: (41) 22 379 65 67. E-mail: norbert.lange{at}pharm.unige.ch
Published ahead of print on 14 January 2008.
Present address: Interlifescience, Via San Gottardo 92, 6900 Massagno, Switzerland.
Antimicrobial Agents and Chemotherapy, April 2008, p. 1366-1373, Vol. 52, No. 4
0066-4804/08/$08.00+0 doi:10.1128/AAC.01372-07
Copyright © 2008, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Letoffe, S., Heuck, G., Delepelaire, P., Lange, N., Wandersman, C.
(2009). Bacteria capture iron from heme by keeping tetrapyrrol skeleton intact. Proc. Natl. Acad. Sci. USA
106: 11719-11724
[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»