Antifungal and antibiofilm activities of selected plant extracts

Aims@#Candida albicans is a regular member of the human microbiota but also one of the most frequent pathogens with a strong biofilm-forming capacity and prominent resistance to antimycotic drugs. The aim of this investigation was to evaluate the anti-C. albicans biofilm activity of ethanolic and methanolic leaf extracts of spinach, Swiss chard and garden orache.@*Methodology and results@#Antifungal activity was established by determining the minimum inhibitory (MIC) and minimum fungicidal concentrations (MFC) by the broth microdilution method. The antibiofilm activity was tested by the tissue culture plate method, followed by the determination of the biofilm inhibition. Results showed that all extracts exhibit antifungal activity, with the MIC value of 62.50 μg/mL. This is in accordance with the results of antibiofilm activity, where extracts showed the ability to decrease the biofilm-forming capacity at sub-inhibitory concentrations. Overall antibiofilm effect of spinach extracts were narrow, but biofilm inhibition activity was observed at 31.25 μg/mL of ethanolic extract. Considering the dilution range, garden orache extracts had the broadest antibiofilm activity, with a biofilm inhibition of 20.96-38.10% and 12.11-12.97% for ethanolic and methanolic extracts, respectively. Swiss chard ethanolic extract inhibited biofilm from 14.52% to 31.39% and methanolic from 37.66% to 44.70%.@*Conclusion, significance and impact of study@#Study revealed that investigated plant extracts have antifungal and antibiofilm potential against C. albicans, which could be important in light of its emerging resistance to synthetic drugs, as well as the possible toxicity of antimycotics.

Comparison of the Minimum Fungicidal Concentration of Clotrimazole, Ketoconazole, Miconazole and Terbinafine Against Clinical Isolates of Dermatophytes.

Superficial fungal infections affect millions of people worldwide. Earlier most dermatophyte strains had relatively restricted geographical distribution. But currently, dermatophytosis has become one of the most common human infectious diseases worldwide. Fungal infections are common in hot and humid climate of tropical countries like India. Topical and systemic therapies are commonly used to treat dermatophyte infections.Clotrimazole is one of the most commonly used topical antifungal drugs. This study compared the minimum fungicidal concentration (MFC) of Clotrimazole with Miconazole, Ketoconazole and Terbinafine in skin dermatophytes. The study demonstrated that Clotrimazole had lower MFCs as compared to Ketoconazole and Miconazole against Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum canis. Clotrimazole had comparable MFCs versus Terbinafine against Trichophyton rubrum but it had lower MFCs against Trichophyton mentagrophytes and Microsporum canis. Thus, Clotrimazole is an effective antifungal agent for dermatophytosis even today.The efficacy of Clotrimazole even against strains with intermediate resistance or resistance to the older azole anti fungal drugs reiterate the current decisions of empirical treatment with topical Clotrimazole for the management of superficial dermatophyte infections.

In Vitro Amphotericin B Susceptibility of Korean Bloodstream Yeast Isolates Assessed by the CLSI Broth Microdilution Method, Etest, and Minimum Fungicidal Concentration Test / 대한진단검사의학회지

BACKGROUND: Although amphotericin B (AMB) has a wide spectrum of activity that encompasses the majority of yeast isolates, there have been recent reports suggesting that some yeast isolates exhibit decreased susceptibility to AMB. However, in vitro AMB susceptibility of yeast species isolates from blood cultures in Korea has not been fully surveyed. METHODS: A total of 92 bloodstream yeast isolates from four Korean hospitals, representing 10 Candida species (69 isolates) and 4 non-Candida yeast species (23 isolates) were evaluated. AMB minimum inhibitory concentrations (MICs) were determined by two methods: the CLSI method and Etest. AMB minimum fungicidal concentrations (MFCs) were also determined. RESULTS: For all 92 yeast isolates, the CLSI method generated a restricted range of MICs (0.125 to 4 microgram/mL) with 3.3% exhibiting MICs > or =2 microgram/mL, and the corresponding MFC values ranged from 0.25 to 8 microgram/mL with 26.1% showing MFCs > or =2 microgram/mL. Etest produced the widest distribution of MICs, ranging from 0.03 to 32 microgram/mL. High AMB MICs (> or =0.38 microgram/mL) by Etest was observed in 34.8% of the isolates: Candida krusei (100%), Candida rugosa (100%), Trichosporon asashii (100%), Candida glabrata (82%), and Yarrowia lipolytica (75%). Etest disclosed that all isolates of Candida guilliermondii, Candida lusitaniae, Candida pelliculosa and Kodamaea ohmeri were highly susceptible to AMB (MIC < or =0.19 microgram/mL). CONCLUSIONS: Our study showed that Etest may be more useful to discriminate yeast isolates with reduced susceptibility to AMB, and some isolates of less common yeast species from Korea may have decreased AMB susceptibilities.