An account of Genomic Islands of zoonotic origin Staphylococcus aureus genomes — In silico approach

Genomic Islands (GIs) are commonly believed to be relics of horizontal transfer and associated with specific metabolic capacities, including virulence of the strain. Staphylococcus aureus is a commensal, Gram-positive bacteria found in both animals and humans. Amid stress or immune compromised conditions of the host, the bacteria known to induce diseases. In this study, we predicted GIs, a relative dissection and portrayed significant virulence factors associated with GIs. The study recognized distinct regions of the GIs of S. aureus RF122 which imparted with the other strains. Many GIs of RF122 strain homologous to other strains and sharing common lineage. In spite of its small genome size RF122 strain harbours 18 GIs evident for rapid horizontal gene transfer events during its evolution. It has concluded from the mechanisms involved in gene transfer, phage infections and transposase are important mechanisms of the horizontal transfer in the study strains. Resistance Islands and Pathogenicity islands are common subtypes of predicted GIs of study genomes. Drug resistance and virulence of S. aureus enhanced because of GIs. Another important finding of this study is it also proved S. aureus adopted to host niche because of horizontally acquired GIs. Based on sequence similarity it suggests that ST398 strain has evolved recently. Further, GI Knockout studies needed for validation of role of GIs in transforming commensal to virulent strain.