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Effectiveness of the Photoactive Dye Methylene Blue versus Caspofungin on the C andida parapsilosis Biofilm in vitro and ex vivo
Author(s) -
Černáková Lucia,
Chupáčová Jaroslava,
Židlíková Katarína,
Bujdáková Helena
Publication year - 2015
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12480
Subject(s) - biofilm , methylene blue , ex vivo , caspofungin , microbiology and biotechnology , chemistry , candida parapsilosis , candida albicans , in vivo , agar , nuclear chemistry , in vitro , minimum inhibitory concentration , bacteria , antifungal , biology , biochemistry , photocatalysis , fluconazole , genetics , catalysis
This research studied the effectiveness of the photoactive compound methylene blue ( MB ) activated with red LED light (576–672 nm) compared to that of caspofungin ( CAS ) on 1 Candida albicans and 3 Candida parapsilosis strains. Results were evaluated in terms of SMIC 50 for CAS or in PDI (photodynamic inactivation)‐ SMIC 50 for MB (minimal inhibitory concentration inhibiting sessile biofilm to 50% in comparison to the control without CAS or after irradiation in comparison to the control without MB ). While all strains were susceptible to CAS in planktonic form, the SMIC 50 was determined to be >16 μ g mL −1 when CAS was added to a 24 h biofilm. However, PDI ‐ MIC 50s (1.67 mW cm −2 , fluence 15 J cm −2 ) were 0.0075–0.03 mmol L −1 . For biofilm, PDI ‐ SMIC 50s were in the range from 0.7 to 1.35 mmol L −1 . MB concentration of 1 mmol L −1 prevented a biofilm being formed ex vivo on mouse tongues after irradiation regardless of the application time, in contrast to CAS , which was only effective at a concentration of 16 μ g mL −1 when it was added at the beginning of biofilm formation. PDI seems to be a promising method for the prevention of microbial biofilms that do not respond significantly to conventional drugs.