Fig. 4.

Effect of heat treatment on the conjugation efficiency of a panel of C. difficile strains. A panel of C. difficile strains was used in unheated (dark grey) and heat treated (light grey, 52 °C for 5 min) 8 h conjugations. Strain R7404 showed no significant increase in conjugation efficiency with this treatment and was therefore used in a 24 h conjugation after a more stressful heat treatment (50 °C for 15 min). Each bar represents the mean and standard deviation of data collected from experiments performed in triplicate using biological duplicates. All strains displayed a statistically significant (P < 0.05) increase in conjugation efficiency after heat treatment.