Since its discovery in 2004, livestock-associated MRSA ST398 has emerged as an increasingly common cause of human infections in Northern Europe and a prevalent colonizer of livestock and farm workers in the U.S. and around the world.
Here we propose to sequence the genomes ST398 isolates from five strategically curated strain repositories from food-animals, farmers, veterinarians, and community members. The isolates include:
1) those from serious invasive infections as well as benign colonization to elucidate the virulence factors that facilitate invasive infections;
2) isolates from all of the major commodity food-animal species to reveal if ST398 is truly a generalist or if specific sublineages preferentially colonize certain species;
3) isolates dating back to origin of the ST398 epidemic to facilitate molecular clock analyses and estimation of when the major species jumps took place;
4) isolates from humans with no known livestock exposure that will reveal if ST398 is shifting from a primarily livestock-associated lineage to one that is also established in the community and capable of human-to-human transmission;
5) isolates from diverse geographic locations that will enable us to trace the geographic origins of the ST398 epidemic and dissemination of strains through trade routes.
This project will also examine whether the increasing prevalence strains bearing phage-associated immune evasion complex is due to multiple phage re-infection events versus clonal expansion of a competitive, well adapted strain.
Project Data can also be found at NCBI