Antifungal Activity Of Sertraline In Combination With Fluconazole Against Candida Albicans Biofilm In Vitro

Background:In recent years, The incidence of invasive fungal infections(IFIs), especially Candida infections, has become more and more common in clinic, as the patients who are immuncompromised become increasingly because of organ transplantation, cancer treatment, HIV infection, and extensive use of glucocorticoid, Candida has a total of 81 kinds, but only 11 kinds of pathogenic to human body, of which Candida albicans are most common. Candida albicans is implicated in many biomaterial-related infections. Typically, these infections are associated with biofilm formation. Cells in biofilms display phenotypic traits that are dramatically different from those of their free-floating planktonic counterparts and are notoriously resistant to antimicrobial agents. Formation of Candida albicnas biofilms have important clinical repercussions because of their increased resistance to antifungal therapy, which brought new difficulties to clinical diagnosis and treatment. The number of effective and safe antifungal drugs is limited in clinics. At the same time, along with the large dose and long-term therapeutic and prophylactic use of antifungal drugs, fungal resistance increased rapidly. Candia albicans biofilms have been reported to be resistant to variety of clinical antifungal agents, including fluconazole, a well-tolerated antifungal drugs, commonly used in treatment of candidiasis. Because of exploring a new antifungal drug has a large burden on finance and time, researchers turn to research the antifungal effects of existing drugs. Sertraline is a selective 5-serotonin reuptake inhibitors, commonly used in depression, parkinson disease, phobia and premenstrual syndrome. A few of scholars found that sertraline has a certain inhibitory effect on the vitality of Candida, when they use sertraline in the treatment of premenstrual anxiety patients in clinic. Then the antifungal effect of sertraline began to be concerned.Objective:To determine the antiAiCandida Albicans activity of sertraline in vitro; To assess antifungal activity of sertraline and fluconazole administered alone or in combination against Candida albicans biofilm in vitro, and to evaluate the combined effect of these two drugs, so as to set up the foundation for studing its antifungal mechanism and creat new idea for fungal infection which are associated with biofilm treatment.Method:(1) To identify preserved clinical strains by culturing on Sabouraud- chloramphenicol glucose agar, germ tube test, chlamydospore test, and culturing on CHROMagar, respectively. (2) The minimus inhibitory concentration(MIC) of sertraline, fluconazole to clinical strains were tested by CLSI-M27-A. (3) MTT reduction assay was performed to determine antifungal activity of sertraline and fluconazole administered alone or in combination against Candida albicans biofilm in vitro, and to evaluate the combined effect of these two drugs. (4) Scanning electron microscope(SEM) examination was conducted to assess the effect of fluconazole alone or in combination on morphogenesis of Candida albicans biofilm formation.Result:(1) Identified by the preservation of Ⅰ,Ⅱ and Ⅲ clinical strains were all Candida albicans. (2) The MIC50 of fluconazole for clinical strains Ⅰ,Ⅱ and Ⅲ were respectively 8μg/ml, 8μg/ml and 128μg/ml; The MIC50 of sertraline for clinical strains Ⅰ, Ⅱ and Ⅲ were respectively 14.84μg/ml,14.84μg/ml and 59.375μg/ml. (3) The MIC50 of sertraline for clinical strains Ⅰ, Ⅱ and Ⅲ were 475μg/ml,237.5μg/ml and>475μg/ml respectively, the MIC50 of fluconazole for biofilms cells of all strains were>128ug/ml. Sertraline did not enhance the antifungal effect of fluconazole against biofilm formed by C.albicans Ⅲ, but additive effects were found for the combination of sertraline and fluconazole to block the biofilm formation by C.albicans Ⅰ and Ⅱ (FIC index=0.75,0.75). (4) SEM images showed that the control biofilms (no drug) intertwined to form a coherent woven-like structure, with yeast cells forming aggregates along the hyphae; when use fluconazole alone a small part of biofilm can be damaged, but yeast cells and hyphae can still be seen; Candida albicans biofilm that was treated with fluconazole in combination sertraline were devoid of hyphal growth, exclusively consisted of aggregates of blastospores.Conclusion:(1) Sertraline has antifungal effects on medically important Candida albicans. (2) Candida albicnas biofilm was resistant to fluconazole; (3) sertraline may increase the sensitivity of biofilm cells of Candida albicans to fluconazole by devoid of hyphal growth.