I cannot personally attest to colloidal silver's effectiveness against staph (or MRSA)... but an acquaintance of mine did gift me a drop of her own silver one day. I had a deep cut on my foot and nothing to bandage it with but some tape...

After I was able to dress the wound fully and saw the amount of dirt and grime that had gotten lodged inside during my walk back, I was nervous at first... but after cleaning it thoroughly, it looked as if the slice had happened with a sanitized surgical knife - no redness, or swelling, or irritation... Needless to say, it healed very speedily with no infection whatsoever.

To quote The Monkees: "Now I'm a believer!" :-D