Fig. 4.

The expression level of the genes (agrD, agrC, agrB, bhp, atlE1, aae, aap, icaADBC and luxS) were assessed by real-time PCR reactions. The expression levels of all tested genes were normalized using the housekeeping gene 16SrRNA. Results are presented as threshold cycles (Ct) values of genes expressed in biofilm cells of S. epidermidis CIP 444 (a–i) during 7 days (day 1 to day 7), in addition to planktonic (day 0). Ct values ≥ 30 were chosen as very low or no expression. Columns with different annotation letters (a,b,c.) indicate days with a significant difference in gene expression with a p-value <0.05 based on Duncan's multiple range test.