MRSA is not that common. Most people get it from contact in medical facilities, but some people (very few) do carry it around.
When someone contracts it and becomes seriously ill, it usually means they weren't a carrier to begin with, or had an immunodeficiency that allowed the pathogen to overtake an equilibrium with their immune system. They do hardcore contact tracing if someone actually dies from it, and if nobody around this guy had it...quite suspicious. That's all I'm saying.