Fig. 3. Contribution of biofilm-associated C. difficile to cause recurrent disease.

A Timeline of events from the biofilm donor model (Model D, blue arrow) prior to support structure transfer, and two further models; a control model (Model C, red arrow) inoculated with C. difficile spores, and a biofilm recipient model (Model R, green arrow), which did not receive spores, but received the biofilm support structures from model D (broken blue arrow). B Recoveries of luminal C. difficile (total viable counts – TVC; spores - Sp) from model C (red line) and model R (green line) and subsequent periods of toxin detection (arrows). Solid lines are C. difficile total viable cells and broken lines are spore recoveries. Results expressed as mean log₁₀ cfu/mL from two biological replicates. C Quantitative PCR enumeration of selected luminal microbiota populations from model C (whole lines) and model R (dotted lines) immediately prior to clindamycin instillation (pre-clindamycin), during clindamycin therapy and throughout CDI development and progression. Results expressed as mean log₁₀ copy number per µL of luminal fluid from two biological replicates. All error bars represent the standard deviation.