Figure 1. The CFU/ml formed on BHIS agar by nine C. difficile isolates after incubation with germinants.

Spores of C. difficile were heat treated at 60°C for 25 min. CFU/ml were then enumerated on BHIS agar after 2 h incubation of spores with either i) BHIS supplemented with 0.1% (w/v) taurocholate (filled bars); ii) BHIS supplemented with 0.1% (w/v) taurocholate and 2 mM chenodeoxycholate (empty bars, diagonal lines); iii) BHIS alone (empty bars); or iv) dH₂O (filled bars, diagonal lines). Colony formation was expressed as the percentage of CFU/ml observed compared to the CFU/ml observed after incubation with the positive control, BHIS supplemented with taurocholate. The data represent the average of three independent experiments and error bars indicate the standard errors of the means.