Analysis and Comparative Genomics of the SXT/R391 Family ICE, pMERPH

The aim of this study was to analyse pMERPH, the first integrative and conjugative element (ICE) of the SXT/R391 family isolated in the United Kingdom and to determine its relationship to other members of the SXT/R391 family of ICEs. Whole Genome Sequencing of Escherichia coli isolate KH802 (which contains the ICE pMERPH) was performed using Illumina sequencing technology. pMERPH was evaluated by de novo assembly of the sequenced genome, via gene prediction and annotation tools, and phenotypic analysis via comparative genomics to other members of the SXT/R391 ICEs. pMERPH has a size of 110 Kb and has 112 predicted ORFs making it one of the bigger SXT/R391 ICE’s thus far characterised. The “Hotspot regions” of the element were found to contain putative restriction digestion systems, insertion sequences and heavy metal resistance genes that give resistance to mercury and arsenate. pMERPH is closely related to the SXT-like elements from widely dispersed geographic areas. The sequencing of pMERPH increases the knowledge of the earliest isolated SXT/R391family members and may provide insight on the emergence of such elements.