Candida albicans has the ability to colonize various materials used in prostheses. In this report, we have studied the kinetics of biofilm formation on prosthetic materials and their susceptibility to fluconazole at various stages of development. Results indicated that C. albicans efficiently adheres to and colonizes polystyrene, polyvinylchloride, silicon, and polycarbonate surfaces. Candida albicans biofilm formation was observed to be both strain- and substrate dependent. Adhesion of cells to solid substrates was found sufficient to induce fluconazole resistance. Drug susceptibility at different stages of biofilm growth showed that Candida biofilms on these substrates are highly resistant to fluconazole. The study focuses on the limitations of fluconazole to combat biofilm-related infections and emphasizes the need for better therapeutic strategies against prosthesis-associated C. albicans infections.
"None of the authors of this manuscript has any financial or personal relationship with other people or organizations that could inappropriately influence their work.. prescribed drug fluconazole (Shinde et al., 2012). Additionally , biofilms may act as reservoirs of infectious cells to cause re-infections (LaFleur et al., 2006). "
[Show abstract][Hide abstract] ABSTRACT: Infections associated with the biofilms of Candida albicans are a challenge to antifungal treatment.
Combinatorial therapy involving plant molecules with antifungal drugs would be an effective complementary
approach against drug-resistant Candida biofilms. The aim of this study was to evaluate the efficacy of three bioactive terpenoids (carvacrol, eugenol and thymol) in combination with fluconazole against planktonic cells, biofilm development and mature biofilms of C. albicans. Activities of the selected molecules were tested using a microplate based methodology, while their combinations with fluconazole were performed in a checkerboard format. Biofilms were quantitated by XTT-metabolic assay and confirmed by microscopic observations. Combinations of carvacrol and eugenol with fluconazole were found synergistic against planktonic growth of C. albicans, while that of thymol with fluconazole did not have any interaction. Biofilm development and mature biofilms were highly resistant to fluconazole, but susceptible to three terpenoids.
Sensitization of cells by sub-inhibitory concentrations of carvacrol and eugenol resulted in prevention of biofilm formation at low fluconazole concentrations, i.e. 0.032 and 0.002 mg ml1, respectively. Addition of thymol could not potentiate activity of fluconazole against biofilm formation by C. albicans. Fractional inhibitory concentration indices (FICI) for carvacrol-fluconazole and eugenol-fluconazole combinations for biofilm formation were 0.311 and 0.25, respectively. The FICI value of 1.003 indicated a status of indifference for the combination of thymol and fluconazole against biofilm formation. Eugenol and thymol combinations with fluconazole did not have useful interaction against mature biofilms of C. albicans, but the presence of 0.5 mg ml1 of carvacrol caused inhibition of mature biofilms at a significantly low concentration (i.e. 0.032 mg ml1) of fluconazole. The study indicated that carvacrol and eugenol combinations with fluconazole would be a potential alternative strategy for prevention and control of biofilm-associated C. albicans infections.
The Journal of General and Applied Microbiology 11/2014; 60(5):163-168. DOI:10.2323/jgam.60.163 · 0.94 Impact Factor
"Biofilms are resistant to antifungal antibiotics, including the most commonly prescribed drug, fluconazole [5,28]. All of the compounds tested significantly inhibited biofilm formation, even at their MIC values. "
[Show abstract][Hide abstract] ABSTRACT: Asaronaldehyde (2, 4, 5-trimethoxybeznaldehyde) is an active component of Acorus gramineus rhizome. This study aims to evaluate the anti-Candida efficacy of asaronaldehyde and its three structural isomers, namely, 2, 3, 4-trimethoxybenzaldehyde, 3, 4, 5-trimethoxybenzaldehyde, and 2, 4, 6- trimethoxybenzaldehyde.
Susceptibility testing of test compounds was carried out using standard methodology (M27-A2) as per clinical and laboratory standards institute guidelines. Minimum fungicidal concentration (MFC) was determined as the lowest concentration of drug killing 99.9% of Candida cells. The effect on sterol profile was evaluated using the ergosterol quantitation method. Effects on morphogenesis, adhesion and biofilm formation in C. albicans were studied using germ-tube, adherence and biofilm formation assays respectively. Cytotoxicity of test compounds to human RBCs was determined by hemolysis assay.
2, 4, 6-Trimethoxybenzaldehyde exhibited significant anti-Candida activity (P = 0.0412). Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were established as 0.25 and 0.5 mg/mL, respectively. All of the test compounds showed significant inhibition of hyphal form transition in yeast at MIC/2 and MIC/4 values. 3, 4, 5-Trimethoxybenzaldehyde and 2, 4, 6-trimethoxybenzaldehyde inhibited adhesion and biofilms. A hemolytic assay of these compounds revealed that they were non-toxic at MIC values. Asaronaldehyde reduced sterol content.
Asaronaldehyde and 2, 4, 6-trimethoxybenzaldehyde showed anti-Candida efficacy.
Chinese Medicine 09/2013; 8(1):18. DOI:10.1186/1749-8546-8-18 · 1.49 Impact Factor
"Previous works in our laboratory and by various other researchers have shown that Candida biofilms are resistant to antifungal antibiotics, including the most commonly prescribed drug, fluconazole (Ramage et al. 2005; Shinde et al. 2011). Methanolic fraction of A. calamus rhizome is reported to exhibit significant inhibition of biofilms compared to conventional antifungals (Subha and Gnanamani 2008). "
[Show abstract][Hide abstract] ABSTRACT: Anti-Candida potential of Acorus calamus rhizome and its active principle, β-asarone, was evaluated against the human fungal pathogen, Candida albicans. β-Asarone exhibited promising growth inhibitory activity at 0.5mg/ml and it was fungicidal at 8mg/ml. Time dependant kill curve assay showed that MFC of β-asarone was highly toxic to C. albicans, killing 99.9% inoculum within 120min of exposure. β-Asarone caused significant inhibition of C. albicans morphogenesis and biofilm development at sub-inhibitory concentrations. Our data indicate that the growth inhibitory activity of β-asarone might be through inhibition of ergosterol biosynthesis. Hemolytic assay showed that β-asarone is non-toxic, even at concentrations approaching MIC value. Our results suggest that β-asarone may be safe as a topical antifungal agent.
Phytomedicine: international journal of phytotherapy and phytopharmacology 11/2012; 20(2). DOI:10.1016/j.phymed.2012.09.029 · 3.13 Impact Factor
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