Dormancy of Candida albicans cells in the presence of the polyene antibiotic amphotericin B: simple demonstration by flow cytometry

Flow cytometry light scattering was used to monitor size increase of Candida albicans (isolate ATCC 10231) cells in the presence or absence of the antifungal drug amphotericin B (AmB). This non-invasive and descriptive method allowed for the differentiation of dead and dormant sub-populations of cells. When inoculated into a growth medium without AmB, a progressive increase in light scattering was observed over a period of approximately 4 h, but without proliferation of the yeast. After this period, the light scattering distribution regressed to baseline level, whereas cell proliferation started. In the presence of AmB, all the cells shrank in size within approximately 4 h and proliferation was temporarily halted. However, in the presence of 0.4 µM AmB, a progressive increase of light scattering occurred after 21 h which was similar to that observed within the first 4 h in the absence of the antifungal. After approximately 24 h of incubation at this concentration of AmB, proliferation resumed.These observ...