The trends observed in the transcription of the PaLoc genes and the expression of the toxins generally conform to previously reported data [18, 19] . It should be noted that the up-regulation in time of tcdC transcription was not observed in earlier studies on C. difficile VPI10463 [16] but is consistent with more recent reports [18, 19] . We observed an increase in transcription of the PaLoc genes in time, and a concomitant increase in toxicity of culture supernatant in stationary phase that can be attributed to the toxins as it is fully neutralized by anti-toxin against toxin A and B.