S. epidermidis transcriptome in mixed species biofilms and validation. Figure 4A represents a heat map with hierarchal clustering of the samples. Red color indicates upregulation and light blue down regulation. S1, S2, S3 and SC1, SC2 and SC3 represent 3 biological replicates of single species S. epidermidis and mixed species biofilms respectively. Two down regulated genes (lrgA and lrgB) and 3 upregulated genes (prfA, hrcA and guaC) were evaluated for microarray validation (Figure 4B). Results for microarray are shown in white bars and real-time RT PCR in gray bars. Real-time RT PCR shows consistent results with microarray (p > 0.05 for each gene tested).