Open AccessSynergistic effect of doxycycline and fluconazole against C andida albicans biofilms and the impact of calcium channel blockers
Author(s) -
Gao Yuan,
Zhang Caiqing,
Lu Chunyan,
Liu Ping,
Li Yan,
Li Hui,
Sun Shujuan
Publication year - 2013
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/1567-1364.12048
Subject(s) - fluconazole , candida albicans , biofilm , minimum inhibitory concentration , microbiology and biotechnology , corpus albicans , doxycycline , calcium channel , biology , checkerboard , calcium , pharmacology , azole , broth microdilution , antimicrobial , antibiotics , antifungal , chemistry , bacteria , genetics , organic chemistry
C andida albicans is a clinically important fungus and is capable of forming biofilms, which contributes to the emergence of fluconazole resistance. Here, sessile minimum inhibitory concentrations ( SMIC s) of fluconazole combined with doxycycline against biofilms of C . albicans were determined, and the results of SMIC s were compared with minimum inhibitory concentrations ( MIC s) of planktonic cells. SMIC s and MIC s were determined by microdilution checkerboard method, and the interactions between two drugs were interpreted by two models of fractional inhibitory concentration index and the percentage of growth difference (△ E ). For the biofilms formed over 4, 8, and 12 h, synergism was displayed by the combination of doxycycline(1–64 mg L −1 ) and fluconazole, and the fluconazole SMIC reduced from 64–512 mg L −1 to 1–16 mg L −1 against all the tested isolates. Calcium homeostasis is an important factor in growth of C . albicans . In this study, the impact of calcium channel blocker on the drug combination was observed by plate streaking and determined by liquid methods quantitatively. Obvious enhancement of antifungal effect appeared by combination of three drugs. These results show us that fluconazole combined with doxycycline could be effective against C . albicans biofilm, and the combined antifungal mechanism is associated with calcium.