Not an expert but zero I reckon. Okay probably a lot do not have any reported cases, but that does not mean it is not there.
It also depends on which strains you are talking about, some are harmless (living in the nose of people, no issues), some are not dangerous (impetigo) and then we have the highly resistant types.
Open wounds are great for the stuff. But from (friends) experience staph does not like the sun.
Medical facilities have a lot of circulating humans moving between different facilities.
