Sensitisation of <i>Candida albicans</i> to killing by low‐power laser light

Wilson, Michael; Mia, Nadia

doi:10.1111/j.1600-0714.1993.tb01088.x

Cited by 104 publications

(74 citation statements)

References 16 publications

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“…[17][18][19][20][21][22][23][24] The results of the present investigation demonstrated significant reduction of CFU/mL of C. albicans from tongues of mice after 400, 500, and 1000 mg/L of Photogem associated with LED light (305 J/cm 2 ) (455 and 630 nm). There is only one report describing a dose-dependent photoeradication of C. albicans in an immunodeficient murine model.…”

Section: Discussionsupporting

confidence: 55%

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Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Mima

Pavarina

Dovigo

et al. 2010

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, an

141

130

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Objective. In vivo studies of antimicrobial PDT in animal models of oral candidosis are scarce and the association of porphyrin and LED light has not been evaluated for in vivo photoinactivation of Candida. In this study the effectiveness of photodynamic therapy (PDT) on the inactivation of Candida albicans in vivo was evaluated. Study design. Seventy-one 6-week-old female Swiss mice were immunosuppressed, provided tetracycline to their drinking water, then orally swabbed with a suspension of C. albicans (10 7 CFU/mL). Four days after oral inoculation, PDT was performed on the dorsum of the tongue after topical administration of Photogem at 400, 500, or 1000 mg/L and followed 30 minutes later by illumination with LED light (305 J/cm 2 ) at 455 or 630 nm (n ϭ 5 each). After swabbing to recover yeast from the tongue, the number of surviving yeast cells was determined (CFU/mL) and analyzed by ANOVA and Holm-Sidak tests (P Ͻ .05). Animals were humanely killed, and the tongues surgically removed and processed for histological evaluation of presence of yeast and inflammatory reaction. Results. PDT resulted in a significant reduction in C. albicans recovered from the tongue (P Ͻ .001) when compared with mice from the positive control group. There was no difference between the concentrations of Photogem and LED light wavelengths used. Histological evaluation of the tongue revealed that PDT causes no significant adverse effects to the local mucosa. Conclusion. PDT promoted significant reduction in the viability of C. albicans biofilm without harming the tongue tissue.

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Section: Discussionsupporting

confidence: 55%

“…are susceptible to photoinactivation. [17][18][19][20][21][22][23][24] Usually, dyes (toluidine blue and methylene blue) and porphyrins are used as PS combined with red laser light. However, light sources with simpler technology and lower cost than lasers, such as light-emitting diodes (LED), have been successfully applied in PDT.…”

mentioning

confidence: 99%

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Mima

Pavarina

Dovigo

et al. 2010

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, an

141

130

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“…PDT has also been demonstrated against the fungal dermatophyte Trichophyton rubrum (18). Other in vitro studies have demonstrated the possibility of photosensitizing C. albicans to light-induced cellular damage by using a variety of compounds (1,22,25). We found that C. albicans was exquisitely sensitive to the phototoxic effects of Photofrin, a compound that is already approved for clinical use, in concentrations as low as 1 g/ml in vitro.…”

Section: Discussionmentioning

confidence: 62%

Susceptibility of Candida Species to Photodynamic Effects of Photofrin

Bliss¹,

Bigelow

Foster

et al. 2004

Antimicrob Agents Chemother

149

126

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The in vitro susceptibility of pathogenic Candida species to the photodynamic effects of the clinically approved photosensitizing agent Photofrin was examined. Internalization of Photofrin by Candida was confirmed by confocal fluorescence microscopy, and the degree of uptake was dependent on incubation concentration. Uptake of Photofrin by Candida and subsequent sensitivity to irradiation was influenced by culture conditions. Photofrin uptake was poor in C. albicans blastoconidia grown in nutrient broth. However, conversion of blastoconidia to filamentous forms by incubation in defined tissue culture medium resulted in substantial Photofrin uptake. Under conditions where Photofrin was effectively taken up by Candida, irradiated organisms were damaged in a drug dose-and light-dependent manner. Uptake of Photofrin was not inhibited by azide, indicating that the mechanism of uptake was not dependent on energy provided via electron transport. Fungal damage induced by Photofrin-mediated photodynamic therapy (PDT) was determined by evaluation of metabolic activity after irradiation. A strain of C. glabrata took up Photofrin poorly and was resistant to killing after irradiation. In contrast, two different strains of C. albicans displayed comparable levels of sensitivity to PDT. Furthermore, a reference strain of C. krusei that is relatively resistant to fluconazole compared to C. albicans was equally sensitive to C. albicans at Photofrin concentrations of >3 g/ml. The results indicate that photodynamic therapy may be a useful adjunct or alternative to current anti-Candida therapeutic modalities, particularly for superficial infections on surfaces amenable to illumination.Photodynamic therapy (PDT) is a process in which cells are treated with an agent that makes them susceptible to killing by exposure to light. These agents, called photosensitizers, are generally macrocyclic compounds that exhibit no or minimal inherent toxicity but result in the generation of cytotoxic reactive oxygen species when excitation occurs with light of the appropriate wavelength. PDT has been applied most extensively in the treatment of neoplasms and shows promise as a novel therapy for some non-neoplastic disorders (4, 11). Photofrin is a photosensitizer that has been the subject of intensive investigation (4). Derived from acid treatment of hematoporphyrin, this compound has been approved by the U.S. Food and Drug Administration for the treatment of endobronchial and esophageal tumors (11) and is currently in clinical trials for several other indications.Although PDT is becoming established as a treatment modality to augment conventional chemotherapy and radiation in the oncologic literature, much less is known about the effects of photosensitizers on fungi of medical importance. Candida species have become increasingly prevalent as causes of both mucocutaneous and systemic infection in immunocompromised patients (3). Moreover, resistance of Candida to traditional antifungals such as fluconazole is increasing, with some species such as Cand...

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“…This is the first report of antimicrobial photoinactivation of C. neoformans. Antimicrobial PDT has been extensively used for C. albicans with a panel of photosensitizers including PEI-ce6, methylene blue, toluidine blue, rose Bengal, and Photofrin (2,11,44,47). Interestingly, treatment of C. albicans required 10 times more PEI-ce6 than treatment of bacterial cells; this result may have had to do with the larger size of the fungal cells (44).…”

Section: Resultsmentioning

confidence: 93%

Susceptibility of Cryptococcus neoformans to Photodynamic Inactivation Is Associated with Cell Wall Integrity

Fuchs

Tegos

Hamblin

et al. 2007

Antimicrob Agents Chemother

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Photodynamic therapy is a rapidly developing antimicrobial technology which combines a nontoxic photoactivatable dye or photosensitizer with harmless visible light of the correct wavelength to excite the dye to its reactive triplet state to generate reactive oxygen species toxic to cells. In this report we present evidence that the fungal pathogen Cryptococcus neoformans is susceptible to photodynamic inactivation by use of a polycationic conjugate of polyethyleneimine and the photosensitizer chlorin(e6). A C. neoformans rom2 mutant, with a mutation involving a putative Rho1 guanyl nucleotide exchange factor that is part of the protein kinase C-cell wall integrity pathway, demonstrated a compromised cell wall and less (1,3)␤-D glucan than the wild-type strain and increased accumulation of PEI-ce6 as assessed by fluorescence uptake and confocal microscopy. Interestingly, C. neoformans rom2 was hypersusceptible to photodynamic inactivation and coincubation of wild-type C. neoformans strain KN99␣ with caspofungin-enhanced photoinactivation. These studies demonstrated that C. neoformans is sensitive to photodynamic therapy and illustrated the significance of cell wall integrity in microbial susceptibility to antimicrobial photodynamic inactivation.

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Sensitisation of Candida albicans to killing by low‐power laser light

Cited by 104 publications

References 16 publications

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

Susceptibility of Candida Species to Photodynamic Effects of Photofrin

Susceptibility of Cryptococcus neoformans to Photodynamic Inactivation Is Associated with Cell Wall Integrity

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