Overall, the logarithmic growth phase was associated with lower transcription levels of the PaLoc genes and by entering into the stationary phase increasing transcription levels of PaLoc genes were found, as previously described for tcdR, tcdE, tcdB and tcdA [16, 18, 19] and tcdC [18, 19] (Figure 2 ). The transcription levels of tcdR in wild type and CT::tcdC strains increased approximately 100-fold between 6 and 24 hours post inoculation ( Figure 2A ). Though the expression of tcdR was, on average, 3-fold higher at the various time points in the CT::tcdC strains compared to the wild type, this difference was not statistically significant ( Figure 2A , all p values $0.088). Similarly, we observed a 10-to 100-fold increase in the transcription levels of tcdB ( Figure 2B ), tcdE ( Figure 2C ), tcdA ( Figure 2D ) and tcdC ( Figure 2E ) when comparing values from the logarithmic growth phase with those observed in the stationary growth phase. The expression levels of tcdB, tcdE, tcdA and tcdC were, on average, 1.5-fold, 2.5-fold, 1.4-fold and 1.7fold higher, respectively, in the CT::tcdC strains compared to the wild type. With one exception, these differences were not found to be significant. The transcription level of tcdB in the CT::tcdC1 strain is significantly (P = 0.046) higher compared to wild type level at 8 hours post inoculation ( Figure 2D ). However, no significant differences are found between the wild type and CT::tcdC strains at any of the other time points.