FIG. 3.

Comparison of alamarBlue assay with manual counting assay for determination of the relative susceptibilities of A. castellanii (a) and A. polyphaga (b) to chlorhexidine over 96 h. Live cells (grey bars) and dead cells (white bars) were determined by trypan blue staining. The effect of chlorhexidine was measured in parallel cultures by determining the percent alamarBlue reduction relative to that for the untreated control cultures (closed circles). Note the comparable results obtained by both methods, which showed a linear correlation for both A. castellanii and A. polyphaga (P < 0.05). The results are expressed as the means for triplicate cultures ± SEs.