OK, biologist here.
We ALL carry staph. At least, we do if we ever had pimples in our teens. Pimples are caused primarily by staph. To be more precise, Staphylococcus aureus (aka "golden staph").
These infections (including pimples) generally take hold around a sweat gland or hair follicle, or other break in the skin. We all know the drill.
Occasionally when conditions are especially favourable (to the bugs) a pimple grows to boil proportions. Warm, moist areas are ideal incubation. Washing regularly and getting air to the place would help. It's summer - get him to wear a caftan. Or a kilt, and go without knickers entirely. difficult child 1 calls it "commando style"; or "letting the boys out for some air".
Staph infections CAN become a problem when it gets to the boil stage. Yes, a staph boil (ANY staph boil) can get into the bloodstream and go septic. You should be on antibiotics at that stage.
Staph infections are generally extremely painful - I remember when easy child was getting one on her finger (through an almost microscopic split in her skin) she was crying in pain and we couldn't see a mark on her. Next morning, there was a tiny white dot and her finger was red and swelling up. I lanced the tiny white dot (I use a hypodermic needle for the job - much kinder than a pin). To sterilise a lance, pass it through the flame of an alcohol burner or a lighter. It works for microbiologists...
MRSA is a particular "breed" of Staph aureus, in the same way that Dalmation is a spotted dog (but is still a dog that eats dog food,chases a ball, will interbreed with any other kind of dog). MRSA has developed in the world because of over-use of antibiotics. We've done it to ourselves, folks. You're not likely to have MRSA unless you've either contracted it somehow (usually from places where it is most commonly found, such as hospitals) or magically developed your own strain of it (most unlikely). "MRSA" stands for "Methycillin-Resistant Staph Aureus". It used to stand for "Multi-Resistant Staph Aureus". There are other multi-resistant bacteria which are even more of a worry.
In your body, MRSA will do exactly what any Staph aureus will do, and nothing more. It's no more virulent. It's just that if a doctor feels you should take antibiotics for your staph, the antibiotics won't work too well, if your infection is MRSA. You need your body to do the job. In most cases, your own body defences will deal with it. It's mainly a problem in people with compromised immune systems.
Streptococcus is another bug we get so often they virtually live in us permanently. If you are prone to regular sore throats, you may well be harbouring a constant low-grade Strep B infection. Again, no need to take antibiotics unless it's bothering you, or you live with someone with a compromised immune system.
Strep B lives in your airways. It's a very important reason for surgeons to wear those face masks. If you ever see a surgeon with his nose poking over his mask, get cranky with him. It's not on. That's how patients can get Strep B infecting their wounds, and that can be nasty. Watch those reality TV medical shows (especially the plastic surgery ones) and then think about how many people get post-op wound infections...
Now, Strep B lives in airways mainly. Lots of air. Lots of oxygen. Staph aureus lives on the skin, mostly. Lots of air, lots of oxygen. These are bacteria which are reproducing AEROBICALLY (ie in oxygen). It's what our body defences are used to. We live in balance with the bugs.
BUT - when they get past our skin (the first line of defence) we begin to have problems. That's when these bugs can begin to multiply ANAEROBICALLY (ie without oxygen). Yes, they can do it. They are adaptable little suckers.
If you have a staph boil, it hurts a lot. It produces a lot of thick pus in a short time and this builds pressure; plus the pain receptors in the area are all firing off and tissues are swollen. OUCH. If it burrows in deeper and heads for the lymphatic system, you will see the redness running along the lymphatic channels like red lines. Get thee to a doctor fast, for antibiotics.
Now, if you are darned unlucky (and/or had a sore throat when you began picking at the boil or when the boil was forming) you can get Strep B bugs in there as well. Remember, these are ordinary, otherwise fairly safe bugs. But together, growing anaerobically in a boil, it can become flesh-eating time. THAT is what you really have to watch for.
What does it look like?
when the two bugs are working together, you will find over time that the centre of the boil will be open and looking like it's healing. You will have either lanced it or it will have broken, by this time. And that is good - it gets air to it. Once the bugs are dividing without oxygen, the oxygen becomes like a poison to them.
So the centre of the boil will be exposed and red but no longer much pus. A scab may form but it will not have anything to hang onto, so it keeps coming away.
The worrying part is the edge, where you can get the most pus formation. If the skin over this area is looking moist and soggy, then you could have Strep B in there as well. The two bugs work to first separate the skin away form the tissues underneath (the strep does this) then the staph creates a lot of pus to force it away further. The Strep then moves in a bit deeper, now that Staph has forced a bit more room. And so on - it will keep growing, widening the margin.
This is what happened to easy child when she got that boil on her finger. That's when our microbiologist neighbour taught me all this, and I taught the doctor (who did know it, but he didn't know the microbiologist's tricks). It can be very frightening when this happens, especially to your child. You see the boil grow almost while you look at it. Remember, easy child's started with an almost microscopic dot on her finger, but within a couple of days the thing was the size of a postage stamp and doubling in size every day.
Diagnosis - these days most pathology tests are automated. There is plenty of pus to culture with these boils, but unless you ask for the tests to be done the right way, you could get a fairly borderline result because the standard tests do not think about these bugs growing without oxygen. It's unusual.
So we were told to request it to be cultured for Staph A as well as Strep B, aerobically and anaerobically. About 12 years ago I got a boil on my finger like easy child's and was away from home (my mother's funeral) and had to explain to a doctor who didn't know me, how I wanted it cultured. I then had to explain that I was going to treat myself without antibiotics.
Treatment - antibiotics (unless you're severely allergic, as I am). But since these infections can often be on an extremity (toe, or finger) where blood circulation isn't as good, antibiotics don't always work too well. This can scare you into thinking you have MRSA. So you need to improve your circulation - just keep the wound area warm, if it's on a limb.
And now for the magic trick from the microbiologist. Run this past the doctor for assurance, but you can do this while taking antibiotics, it can only help.
The trick is - heat, as hot as you can stand it, applied to the wound area, every three to four hours. Soaking a foot or hand with a boil in hot salty water is great. In my case, I walked around the motel with my finger in a glass of salty water, which I would reheat in the microwave oven every so often.
You need to do the three to four hour trick at least three times in succession, on three consecutive days. Each time you do it, it interferes with the natural cell division (reproduction) of the bacteria. They have to start all over again. And if you do it to them AGAIN, they have to AGAIN start over. Enough times, and the bacteria get too old (too big) to divide and your body can finish the job.
A warning - if you can, and the infection is serious enough, take the antibiotics. Take them according to directions or you risk developing a resistant bug in your body. Not good. Antibiotics should clear up one of these infections within two to three days. Finish the course anyway.
The hot water method - it can take a week or more. You have to stick at it. It's good to do it to help the antibiotics (and the heat increases blood flow to the boil, which helps the antibiotics do their job even better). It's just that if you happen to have a resistant bug, and/or you can't take antibiotics, you can still beat the infection. It just is more difficult and takes longer.
For those with an even more scientific bent, dabbing hydrogen peroxide on one of these boils can also help - it gives these anaerobic bugs a fast shot of oxygen. But do follow careful infection control procedures - do not back-contaminate your bottle of peroxide. Also be aware, that if you have the Staph-Strep combination, the peroxide won't reach all the bugs. Some of them will be hiding right at the margin of the wound, under that edge of soggy skin.
Basically, for a bad boil or one that is growing, it's definitely see a doctor time, but not necessarily time to panic.
by the way, I haven't had a Strep-Staph combo infection since. I regularly was getting a Staph infection beside my toenail, though, which I finally beat with a wedge resection.
Marg