What is the gene inside Staphylococcus aureus that makes it need to live inside those type of environments?

Question: What is the gene inside Staphylococcus aureus that makes it need to live inside those type of environments?
- Keywords:
  aureus,
  environments,
  gene,
  staphylococcus
Asked by to Jim on 17 Jun 2011. This question was also asked by .
- Jim Caryl answered on 17 Jun 2011:
  
  Staphylococcus aureus have evolved with humans, and our ancestors from whom we descended, for millions of years. Over the years it has evolved a whole suite of many different genes that are slightly different from its cousins that live elsewhere. One such cousin is Staphylococcus epidermidis, and this lives on the skin of just about everyone. They’re both still highly related, but they have many genes that are slightly different to each other, and they each have genes that the other one doesn’t have at all.
  
  So there is no one gene that makes one species different from another, it is a combination of many new genes, and some slightly changed genes that makes S. aureus happier to live in your nose than on the back of your hand.

Question: What is the gene inside Staphylococcus aureus that makes it need to live inside those type of environments?