Fig. 3.

Germination and outgrowth studies of C. difficile to determine if 15 min of heat shock impairs spore germination or the subsequent cell division. (A) Germination study. Optical density (OD₆₀₀) reductions of heavily inoculated BHI spore suspensions, incubated at 37°C for 7 h, are similar for heated and nonheated spores, indicating normal germination of heated spores. Only PCR ribotype 078 and the ATCC strain are shown; results are means ± standard deviations. (B) Outgrowth study. Enumeration of ethanol-resistant cells from aliquots in Fig. 3A after 7 h of incubation. Countable colonies on blood agar indicate adequate cell division. Reduced counts after heat shock with 85°C (and normal germination shown in Fig. 3A) indicate impaired cell division. Dots represent replica averages; results are means (solid bars) ± 95% CI.