Fig. 1.

Comparative phenotypic properties of R20291 and CRG20291. a. Strains were cultured for 72 h in BHIS and colony forming units (CFU) were determined by serial dilutions and plating (shaded bars). The activity of the toxin production in cell culture supernatants was determined by titrating out toxin activity on Vero cells (triangle shapes). b. Virulence of C. difficile strains in hamsters. Hamsters were challenged with 630 (n = 8), R20291 (n = 8) or R20291M (n = 8). Time from infection to clinical endpoint by each strain is presented in hours. The duration of the experiment was set at 336 h. The open triangles were animals not found to be colonised at the end of the experiment. All statistical analyses were performed using the GraphPad Prism 5 (GraphPad Prism Software). Student t-tests were carried out followed by a Mann Whitney test to determine significant difference between groups of animals. P values ≤ 0.05 were considered significant.