Food for thought.........
I only wash my hands when I'm either sure I've handled something with which ingestion should be avoided at all costs, or when it's both convenient and occurs to me. I have no problem eating with automotive ick all over my hands or immediately after gutting a game animal, don't see any problem with the 10 second rule (except for obvious contamination), rarely wash up before meals.
I have good hygiene, just don't worry much about germs. I've been sick 3 times in the last
decade, only one of which I missed a half day of work.
My sister is about the same way. She also happens to be a PhD microbiologist specializing in infectious disease.
MRSA can live up to 90 days on a surface, and people can be unwitting carriers. If there's an outbreak in your area, disinfecting might not be a bad idea - especially if, for whatever odd reason, someone else has been handling your weapon. Of course, if you're an unwitting carrier, you'd just re-infect it the next time you touched it, but that's a whole other problem you've got then.
Staphyloccocus Aureus (Staph) is literally everywhere, just doesn't affect most healthy people. It even lives on your own skin (what do you think causes zits?). It's really only dangerous when it gets into deep wounds, which is why it's such a common post trauma or post surgical infection. Methicillin Resistant Staph (MRSA) is also quite common in hospitals, where that is the most common teatment for regular staph. It's not that big a deal unless it goes untreated. When you really have to worry is with Vancomycin Resistant Staph (VRSA). It's very rare, but often does a great deal of damage before being correctly diagnosed. Vanco is a very heavy duty broad spectrum antibiotic for gram positive bacteria (among other things), and when it doesn't work, you've got problems.
I wouldn't worry too much about contracting necrotizing bacterial infections from you firearm, though.