FIG 1.
Effect of C. difficile VPI 10463 supernatant (Cd-SN) on Vero cell viability in the presence or absence of B. clausii O/C supernatant (OC-SN). Bars represent the percentage of cell attachment (A) or mitochondrial dehydrogenase activity (B) after incubation of Vero cells with the different treatments assayed (control, Cd-SN, OC-SN, and Cd-SN/OC-SN, with or without the protease inhibitors PMSF and EDTA). Vero cells were also pretreated with OC-SN before incubation with Cd-SN (OC-SN/cells – Cd-SN). The percentage of attachment or remaining mitochondrial dehydrogenase activity was calculated as 100 × (A/Ac), where A is the absorbance of treated cells and Ac is the absorbance of untreated control cells. Results were the averages ± standard deviations (SD) from 3 independent assays. **, significant differences from the corresponding control (P < 0.01); ϕ, significant differences from the Cd-SN condition (P < 0.01).