I have had good success with using activated charcoal for nail infections. I get them a lot when I cut my nails (I cut as far down as possible usually and sometimes too far, plus I bite my nails).
What I do is open a capsule of activated charcoal (You can get this at the store in the pharmacy section near the anti-gas stuff like Gas-X, etc.) and pour the contents on the nail and wrap it up good with a band aid or use one of those lovely gauzy finger cuff things they make for finger or toe injuries. The charcoal will draw out the infection in usually a day or two.
This worked on my finger a couple of weeks ago and right now, I have a bad infection in my big toenail which isn't responding well to the charcoal, but I'd say over the years it took care of probably eight out of 10 infections in my nails so I always try it first before anything else.
The charcoal is messy and it will stain stuff (like certain surfaces -- some stained my toilet seat when I applied it over the toilet to catch the excess that fell -- unfortunately some fell on the toilet seat and it was smudged black forever) so be careful what it comes into contact with. Also it will come off your skin. You just have to wash thoroughly with soap and water and it may leave a black residue, but will eventually come off completely in a few soaks.