Absence of amphotericin B-tolerant persister cells in biofilms of some Candida species

Abstract

Biofilms and planktonic cells of five Candida species were surveyed for the presence of persister (drug-tolerant) cell populations after exposure to amphotericin B. None of the planktonic cultures (exponential or stationary phase) contained persister cells. However, persisters were found in biofilms of one of two strains of Candida albicans tested and in biofilms of Candida krusei and Candida parapsilosis, but not in biofilms of Candida glabrata or Candida tropicalis. These results suggest that persister cells cannot solely account for drug resistance in Candida biofilms.

FIG. 1.

Survival of biofilm cells (▴), planktonic exponential-phase cells (•), and planktonic stationary-phase cells (□) of C. albicans GDH 2346 (A) and C. albicans SC5314 (B) exposed to different concentrations of amphotericin B. Results are means ± standard errors of two independent experiments carried out in duplicate.

FIG. 2.

Survival of biofilm cells (▴), planktonic exponential-phase cells (•), and planktonic stationary-phase cells (□) of C. glabrata AAHB 12 (A), C. tropicalis AAHB 73 (B), C. krusei (Glasgow strain) (C), and C. parapsilosis AAHB 4479 (D) exposed to different concentrations of amphotericin B. Results are means ± standard errors of two independent experiments carried out in duplicate.