We controlled critical parameters in our experiments by performing conventional PCRs which confirmed that the disruption of tcdC remained intact throughout the growth curve. Western blot analysis with antibodies raised against a TcdC epitope confirmed that the disruption of the tcdC gene resulted in the absence of TcdC protein ( Figure 1D ). The disruption of the tcdC gene did not affect the growth kinetics compared to the wild type strain ( Figure 1E ).