FIG 5.

Expression of genes encoding cell envelope proteins promotes biofilm formation. Genes encoding putative cell envelope proteins were expressed under the control of an ATc-inducible promoter in C. difficile 630Δerm. The strains were grown in 24-well plates in buffered BHIS containing 1% glucose and 20 ng/ml ATc to induce gene expression during biofilm development. Biofilm formation was assayed by crystal violet after 24-h incubation. Values are normalized to the induced vector control. Symbols indicate values from independent biological replicates, and bars indicate the means and standard deviations for six independent replicates. *, P < 0.05; **, P < 0.01; and ****, P < 0.0001, by 1-way ANOVA and Dunnett’s posttest, compared to the vector control.