ABSTRACT
We investigated a fluconazole-sensitive (MICflu = 5 micrograms ml-1) clinical isolate and a fluconazole-resistant (MICflu > 80 micrograms ml-1) laboratory mutant Candida albicans strain developed from the sensitive one. We studied putative virulence factors including germination, adherence ability to either buccal epithelial cells or acrylate surface, the secreted aspartic proteinase, and the extracellular phospholipase activity of the two strains as well as their growth. The fluconazole-resistant strain proved to be superior to the original strain in all the virulence traits tested. The higher virulence of the fluconazole-resistant strain was also supported by a mouse model. These results suggest that the development of fluconazole resistance can be accompanied by serious morphological and physiological changes: several putative virulence traits, moreover the in vivo virulence can increase simultaneously.
Subject(s)
Candida albicans/drug effects , Candida albicans/pathogenicity , Fluconazole/pharmacology , Animals , Antifungal Agents/pharmacology , Candidiasis/mortality , Cell Adhesion , Drug Resistance, Microbial , Epithelial Cells/microbiology , Female , Humans , Male , Mice , Mouth/cytologyABSTRACT
The effect of fluconazole and the antineoplastic agents etoposide and methotrexate on the growth and adhesion of Candida albicans were studied. All the tested chemicals inhibited the growth and the adhesion of the yeast to buccal epithelial cells, while fluconazole and etoposide inhibited the adhesion to acrylate surface as well. Our experiments also demonstrated that etoposide and methotrexate interfered with the inhibitory effect of fluconazole on both the growth and cell adhesion. While etoposide strengthened the inhibitory effect of fluconazole, in the presence of methotrexate fluconazole showed lower inhibition on both the growth and adhesion.
Subject(s)
Antifungal Agents/pharmacology , Antineoplastic Agents/pharmacology , Candida albicans/drug effects , Fluconazole/pharmacology , Candida albicans/growth & development , Candidiasis, Oral/microbiology , Cell Adhesion/drug effects , Drug Interactions , Epithelial Cells/microbiology , Etoposide/pharmacology , Humans , Methotrexate/pharmacology , Microbial Sensitivity Tests , Mouth Mucosa/cytology , Mouth Mucosa/microbiologyABSTRACT
Hyphal growth of Candida albicans was observed when yeast was cultured at 27 degrees C in liquid media containing 1% Tripcasine and 1.8% cyclodextrins (alpha, beta, and gamma respectively). Tripcasine as the sole nitrogen source did not induce the formation of hyphae of C. albicans, but cyclodextrins, especially CD-beta, were able to induce yeast-mycelial transition. In the TCD-beta media 25-30% septate hyphae form was observed. This study indicates the existence of an uptake system for CDs in C. albicans, provided these compounds are linearised in the medium. The CDs are inducers of hyphae and they may enter the C. albicans cells as linear oligosaccharids.
