title: The use of Chitosan to enhance photodynamic inactivation against Candida albicans and its drug-resistant clinical isolates.
abstract: Drug-resistant Candida infection is a major health concern among immunocompromised patients. Antimicrobial photodynamic inactivation (PDI) was introduced as an alternative treatment for local infections. Although Candida (C.) has demonstrated susceptibility to PDI, high doses of photosensitizer (PS) and light energy are required, which may be harmful to eukaryotic human cells. This study explores the capacity of chitosan, a polycationic biopolymer, to increase the efficacy of PDI against C. albicans, as well as fluconazole-resistant clinical isolates in planktonic or biofilm states. Chitosan was shown to effectively augment the effect of PDI mediated by toluidine blue O (TBO) against C. albicans that were incubated with chitosan for 30 min following PDI. Chitosan at concentrations as low as 0.25% eradicated C. albicans; however, without PDI treatment, chitosan alone did not demonstrate significant antimicrobial activity within the 30 min of incubation. These results suggest that chitosan only augmented the fungicidal effect after the cells had been damaged by PDI. Increasing the dosage of chitosan or prolonging the incubation time allowed a reduction in the PDI condition required to completely eradicate C. albicans. These results clearly indicate that combining chitosan with PDI is a promising antimicrobial approach to treat infectious diseases.
authors.affiliation: Department of Surgery, National Taiwan University College of Medicine, Taipei 100, Taiwan. chintin@ntu.edu.tw.
authors.forename: Hsiung-Fei
authors.initials: HF
authors.lastname: Chien
authors.forename: Chueh-Pin
authors.initials: CP
authors.lastname: Chen
authors.forename: Yee-Chun
authors.initials: YC
authors.lastname: Chen
authors.forename: Po-Han
authors.initials: PH
authors.lastname: Chang
authors.forename: Tsuimin
authors.initials: T
authors.lastname: Tsai
authors.forename: Chin-Tin
authors.initials: CT
authors.lastname: Chen
mesh_terms: D018441:Biofilms; D002176:Candida albicans / Q000302:isolation & purification / Q000502:physiology*; D002177:Candidiasis / Q000188:drug therapy*; D048271:Chitosan / Q000494:pharmacology*; D004396:Coloring Agents / Q000494:pharmacology; D025141:Drug Resistance, Fungal / Q000187:drug effects*; D006801:Humans; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D014048:Tolonium Chloride / Q000494:pharmacology*
chemical_list: D004396:Coloring Agents; D017319:Photosensitizing Agents; D014048:Tolonium Chloride; D048271:Chitosan
references.citation: J Pharm Pharmacol. 2003 Nov;55(11):1451-63
references.pmid: 14713355
references.citation: Antimicrob Agents Chemother. 1990 Oct;34(10):2019-23
references.pmid: 2291669
references.citation: Biomaterials. 2003 Aug;24(19):3213-20
references.pmid: 12763448
references.citation: Aust Endod J. 2009 Apr;35(1):29-33
references.pmid: 19452677
references.citation: J Burn Care Res. 2008 Jan-Feb;29(1):213-21
references.pmid: 18182925
references.citation: J Clin Microbiol. 2003 Jul;41(7):2961-7
references.pmid: 12843027
references.citation: Photochem Photobiol Sci. 2004 May;3(5):436-50
references.pmid: 15122361
references.citation: Lasers Surg Med. 2006 Jun;38(5):468-81
references.pmid: 16788934
references.citation: Lasers Surg Med. 1996;18(3):253-9
references.pmid: 8778520
references.citation: Biomacromolecules. 2003 Nov-Dec;4(6):1457-65
references.pmid: 14606868
references.citation: Br J Dermatol. 2002 Apr;146(4):568-73
references.pmid: 11966685
references.citation: Drug Deliv. 2008 Sep;15(7):417-22
references.pmid: 18712618
references.citation: J Bacteriol. 2001 Sep;183(18):5385-94
references.pmid: 11514524
references.citation: J Microbiol Biotechnol. 2008 Oct;18(10):1729-34
references.pmid: 18955827
references.citation: Int J Food Microbiol. 2001 Dec 30;71(2-3):235-44
references.pmid: 11789941
references.citation: Lasers Surg Med. 2009 Apr;41(4):316-22
references.pmid: 19347938
references.citation: Br J Dermatol. 2003 Feb;148(2):229-32
references.pmid: 12588372
references.citation: Lasers Med Sci. 2010 May;25(3):385-9
references.pmid: 19579004
references.citation: Antimicrob Agents Chemother. 2011 May;55(5):1883-90
references.pmid: 21282440
references.citation: Oral Surg Oral Med Oral Pathol. 1987 Jul;64(1):50-6
references.pmid: 3475658
references.citation: J Microbiol Immunol Infect. 2010 Oct;43(5):416-29
references.pmid: 21075709
references.citation: Br J Dermatol. 2001 Feb;144(2):274-8
references.pmid: 11251558
references.citation: Biomaterials. 1999 Aug;20(15):1407-14
references.pmid: 10454012
references.citation: Antimicrob Agents Chemother. 2010 Feb;54(2):637-42
references.pmid: 20008782
references.citation: J Formos Med Assoc. 1996 Jan;95(1):19-28
references.pmid: 8640090
references.citation: Antimicrob Agents Chemother. 2008 Sep;52(9):3411-3
references.pmid: 18573927
references.citation: J Food Prot. 2009 Aug;72(8):1735-8
references.pmid: 19722411
references.citation: J Photochem Photobiol B. 2007 Jan 3;86(1):43-4
references.pmid: 17067809