Absence of CdeC and CdeM renders <i>C</i>. <i>difficile</i> spores susceptible to ethanol, heat and macrophages.

<p><b>(A)</b> Ethanol 50% resistance of wild-type (white bar), <i>cdeC</i> (gray bar) and <i>cdeM</i> (black bar) spores. <b>(B)</b> Heat resistance of <i>C</i>. <i>difficile</i> wild-type (gray white), <i>cdeC</i> (gray bars), and <i>cdeM</i> (black bars) spores was measured by heat treating aliquots at 75°C for various times, and survivors were enumerated as described in the Material and Method section. <b>(C)</b> Equal amounts of spores derived from <i>C</i>. <i>difficile</i> strains 630<i>erm</i> (wt), <i>cdeC</i>, <i>cdeM</i>, <i>cdeC/cdeC</i> and <i>cdeM/cdeM</i> were boiled 60 min, and the amount of DPA was quantified based on Tb³⁺. The data shown represent the average results from three independent experiments, and the error bars represent standard error from the means. n.s., indicates no significant difference relative to wild-type. <b>(D)</b> Resistance of Raw 264.7 macrophages was determined by infecting at a MOI of 10 with <i>C</i>. <i>difficile</i> 630<i>erm</i> wild-type, <i>cdeC</i> and <i>cdeM</i> after 0,5, 24 and 48 of incubation at 37°C. Asterisks (*) denote statistical difference at <i>P</i> < 0.01 respect to wild-type.