Heat map analysis of selected genes. Heat map analysis of selected genes which were differentially expressed in at least 2 isolate pairs. The results are expressed as fold ratio of gene expression for hVISA/VISA compared to VSSA. Results are presented for all 5 isolate pairs without antibiotic exposure and all 5 isolate pairs after exposure to vancomycin. This figure shows the upper quartile of these selected genes, for the full image please see additional file 1.