It'd be nice to think that infections only happen to unhygienic sick people with rusty wounds who hang out in hospitals, but it's wrong. Yeah, I've had a million cuts too, and a few stitches, and I've never had a serious infection. But I see them ALL THE TIME. I see infections in people who get little cuts, I see them in healthy people, I see them in upscale soccer moms with perfect hygiene and perfect health and no skin breaks whatsoever. It just happens sometimes. Your body is covered in staphylococcus and streptococcus for the most part. There are many types of each. All of them can cause infection. It's a break in the body's natural balance, for whatever reason. One of the staph strains has started causing more frequent nasty infections in people (MRSA), but these type infections have been around since mankind has. The hideous boil covered people in the dark ages, as in The Holy Grail? They had staph, and there weren't hospitals. It is true that being in the hospital increases the risk of MRSA, which is the type of staph that causes more problems. The source of MRSA, the bad stuff, is probably overuse of antibiotics. It started in hospitals, but it is important to realize that resistant staph is now present fairly prominently in the community. Many of you carry it and have no idea. The moral is this: your body is in a fine friendship with the bacteria that live on it. Sometimes, the bacteria just want more out of the relationship, like your girlfriend will around February 14th. Even without any cuts or nicks, infections happens. This probably is not an issue if you're hiking for 4 or 5 days. But if you are going on a month hike, it's pretty important I think. Yeah, you'll probably be fine, but it sure would suck to be unprepared and ruin your patagonia trip when you get a small infection that festers and worsens because you thought you were way too cool to carry appropriate antibiotics.
For whomever asked, cryptosporidium typically clears just fine without treatment. It mostly effects immunosuppressed people, but when ingested in bulk will look like Giardia (crampy, gassy, smelly, watery diarrhea). Azithromycin treats it and is cheap generically. Typically the bad cases come from water parks/swimming pools in foreign countries. But I wouldn't worry about it, it rarely effects those with good health. Nitazoxanide works, but I'd just carry treatment for giardia.