FIG 1.

DPA release from and completion of germination of C. difficile spores given 150-MPa HP treatment. C. difficile ATCC 43601 spores were exposed to 150 MPa of HP for various times as described in Materials and Methods. Samples treated for various times were assayed for DPA release in separate experiments by measuring either DPA released in germination supernatant fluid (white bars) or the percentage of individual spores that had lost DPA (white stippled bars). In the two experiments, the percentages of spores that were phase dark and had thus completed germination were also measured (gray bars and black stippled bars). All values were corrected for the small percentage (<2%) of phase-dark spores in the starting spores and the small percentage (<5%) of DPA that was present in the supernatant fluid or absent from untreated spores, all as described in Materials and Methods. In a separate experiment, <5% of individual C. difficile spores had lost DPA or had become phase dark after 15 min of 150 MPa treatment (data not shown).