Mechanistic Study of the Photodynamic Inactivation of Candida albicans by a Cationic Porphyrin

• DOI: 10.1128/aac.49.5.2026-2034.2005
• Publication Date: 2005-04-26T23:32:47Z
• Authors: S. A. G. Lambrechts; M. C. G. Aalders; J. Van Marle
• Keywords: Cell membrane

The growing resistance against antifungal agents has renewed the search for alternative treatment modalities, and antimicrobial photodynamic inactivation (PDI) is a potential candidate. cationic porphyrin 5-phenyl-10,15,20-Tris(N-methyl-4-pyridyl)porphyrin chloride (TriP[4]) photosensitizer that in combination with light can inactivate bacteria, fungi, viruses. For future improvement of efficacy PDI clinically relevant fungi such as Candida albicans, we sought to understand working mechanism by following response C. albicans exposed using fluorescence confocal microscopy freeze-fracture electron microscopy. events were observed under dark conditions: TriP[4] binds cell envelope none or very little enters cell. Upon illumination membrane damaged eventually becomes permeable TriP[4]. After lethal damage, massive influx into occurs. Only vacuole resistant PDI-induced damage once passes plasma membrane. Increasing incubation time prior did not increase PDI. replacement 100% phosphate-buffered saline (PBS) 10% PBS medium, became during increased dramatically. In conclusion, be successfully inactivated TriP[4], cytoplasmic target organelle. occurred only after death.