I've had to deal with MRSA a couple of times in my life now. Seems that an open wound and the right conditions make it happen - whatever exactly that means. A couple of years ago, my middle finger got infected from what I thought was just a tiny ingrown hair that had just popped out. Within a week, it looked like the top of my finger exploded - most gnarly thing I have ever seen - but I'll spare the pics. Once the wound opened, they took a culture. The original antibiotic did very little. My whole body felt sick from the MRSA infection after just a week - week and a half. After getting the right antibiotic, it cleared up with bandages after about a month or so. It was extremely stubborn and very painful. My finger was the size of two fingers. There is still some damage under the skin to the tissue today.
Both times I have had MRSA, I was told by the doctor to use hibiclens to wash my hands and any open wound with it. It is not cheap, but it is an antimicrobial antiseptic and used by health care folks. The stuff smells like a hospital when you use it and it is a translucent red. It seems to work well on the preventive side and to stop it from spreading.
Now I keep a bottle of hibiclens in the garage at the sink. I use it only when I have open cuts, wounds or even a pimple or ingrown hair now. I am a bit paranoid with all this bacterial infection stuff. But I have not had any issues since using the stuff when needed. I have also recommended keeping this stuff at the shops I work at as well. I think every single machine shop / tool shop I have worked in over the past 25 years has had employees get infected with MRSA. And it is always though an open or untreated wound - I see the tough guys get this more than anyone else - you know, the old "ah its just a little cut" while dripping blood on the floor being a tough guy and no band aid or anything. I also think machine shops see it more now because the coolant used on CNC's is bio-degradable these days and well, bacteria grows in the coolant tanks when not used for a week or so. The stink is really something, but they do make additives I believe...if the shop buys it. I can remember the more toxic coolant was easier on everyone, now a lot of guys have to wear rubber gloves on machines, allergies, etc...sorry getting off topic a bit.
This is just my experience or .02, I am no expert on this stuff. But I have not had any issues since paying closer attention to keeping wounds covered, and using that hibiclens soap when I have a sore or open wound. After washing, use antibiotic ointment if needed and keep the wounds covered and clean.
On the water side of things, I have never had issues there but I primarily ride in the gulf / salt. Here in west central Fl on the gulf, we get the occasional red tide which tends to screw us out of some riding time when it happens. Red tide is an algae bloom that kills tons of fish due to suffocating the waters. It causes breathing problems to anyone or animals on shore or on the water if red tide is present. People do get sick from it, but it does seem like you really have to get in the really bad or thick parts of it like an idiot to get sick from it.
I really hope you guys and your families that are afflicted get better asap. I am doing my best to try not to get it again myself. These infections are nasty and seem to be getting more so as the years go by. Try keeping some of that hibiclens around. I think any pharmacy would have it on the shelf.