amphotericin-b and 6-amino-2-n-pentylthiobenzothiazole

This study presents the efficiency of the experimental antifungal agents 6-amino-2-n-pentylthiobenzothiazole (APB) and the echinocandin micafungin, and amphotericin B against fluconazole-resistant Candida albicans and Candida dubliniensis (MIC95 for fluconazole > 64 mg/l). The benzothiazole APB was less active against C. albicans and C. dubliniensis (MIC80 = 8 - 32 mg/l, MIC95 = 16 - 64 mg/l) than amphotericin B, which was efficient in a concentration range from 0.125 to 2 mg/l. However, the efficiency of micafungin was very high with MIC80, and MIC100 < or = 0.031 mg/l.

Topics: Amphotericin B; Antifungal Agents; Candida; Candida albicans; Candidiasis; Drug Resistance, Fungal; Echinocandins; Fluconazole; Humans; Lipopeptides; Lipoproteins; Micafungin; Microbial Sensitivity Tests; Peptides, Cyclic; Thiazoles

The influence of six antifungal agents on the expression of the fungal iC3b binding protein was studied in germ-tubes and the mycelial form of several Candida albicans strains. All antifungal agents inhibited not only the yeast-mycelial transformation, but also the formation of rosettes consisting of complement-coated sheep erythrocytes (EAiC3b) bound to the mycelial form of C. albicans. Immunofluorescence as well as ELISA, employing the monoclonal antibody OKM-1 which recognizes the alpha chain of human CR3 and which cross-reacts with the fungal iC3b binding protein, revealed that subinhibitory concentrations of 0.1 mg l(-1) (which did not affect the growth of either germ-tubes or the mycelial form of C. albicans) inhibited the expression of the iC3b binding protein, while lower concentrations (0.01 mg l(-1)) allowed a comparable and sometimes even slightly higher expression of this protein, in comparison with the untreated control. However, treatment with antifungal agents apparently did not lead to a major cleavage of the protein. The dependence of the amount of the iC3b binding protein expressed on the concentration of added antifungal drugs and on the morphological forms of individual C. albicans isolates suggests a drug dependent influence on the expression of this protein and a possible association with the changing virulence of C. albicans strains during antifungal therapy.

Topics: Amphotericin B; Animals; Antifungal Agents; Candida albicans; Clotrimazole; Complement C3b; Dose-Response Relationship, Drug; Enzyme-Linked Immunosorbent Assay; Erythrocytes; Fluconazole; Humans; Immunoblotting; Microbial Sensitivity Tests; Nystatin; Receptors, Complement 3b; Rosette Formation; Sheep; Species Specificity; Thiazoles; Tunicamycin