E. coli O157:H7 phage type 21/28 & 32 CGH analysis

Six isolates of PT21/28 and six of PT32 were analysed by CGH using UBECarray3 microarrays (containing probes for E. coli K-12 str. MG1655 and O157:H7 str. EDL933 and Sakai) to define genotypic differences between phage types. gDNA from E.coli O157 str. Sakai was hybridised to all arrays to provide a universal control channel on all arrays. gDNA from 12 PT 21/28 & 32 isolates were labelled with Cy5 and control gDNA from str. Sakai was labelled with Cy3. Test and control gDNA was hybridised to UBECarray3 microarrays. The LOWESS normalised relative signal to the Sakai control channel was used to compare between samples.