Impact of brief, sequential exposure to fluconazole and amphotericin B on the cell surface hydrophobicity of oral Candida albicans isolates obtained from HIV infected patients

Abstract

Cell surface hydrophobicity (CSH) status influences the virulence of Candida albicans isolates and is inextricably involved in candidal adhesion to mucosal and solid surfaces. As the concentration of antimycotic agents reach sub-therapeutic levels at dosage intervals in the oral cavity, the impact of fluconazole and amphotericin B on the CSH of oral C. albicans isolates obtained from Human Immunodeficiency Virus (HIV) infected patients, should be of clinical relevance. Hence, we evaluated using an aqueous-hydrocarbon assay, the CSH of 1,1 isolates of C. albicans following limited (1 hour), sequential (10 days) exposure of the isolates to sub-therapeutic concentrations of fluconazole and amphotericin B. Next, we analyzed the growth curves (computerized turbidometric measurement) of these isolates following such repeated exposure to the antifungals. The reduction in CSH following exposure to fluconazole and amphotericin B was 6.15% (p < 0.05 for 18.18% of the isolates) and 22.80% (p < 0.05 for 54.54% of the isolates), respectively. Analysis of growth curves indicated that the drugs were able to produce a significant fungistatic effect on two of the 11 isolates compared with the controls. Taken together, these data elucidate further pharmacodynamic mechanisms by which antimycotics may operate in vivo in modulating candidal virulence.