I have no experience with colloidal silver, however, I though it advisable that you read this comment from the Mayo Clinic.

Mayo Clinic Housecall
Stay up to date on the latest health information.

Question
Colloidal silver: Is it safe or effective?
My dad takes colloidal silver because he says it helps him maintain good health, and he hasn't been sick in years. But is colloidal silver safe, and is there any evidence that it does improve health?

Answer
from Brent A. Bauer, M.D.
Colloidal silver isn't considered safe or effective for any of the health claims manufacturers make. Nor is it an essential mineral, as some sellers of silver products claim.
Colloidal silver products are made of tiny silver particles suspended in a liquid — the same type of precious metal used in jewelry, dental fillings, silverware and other consumer goods. Colloidal silver products are usually marketed as dietary supplements that you take by mouth. Colloidal silver products also come in forms to spray, to apply to your skin or to inject.
Manufacturers of colloidal silver products often claim that they are cure-alls, boosting your immune system, fighting bacteria and viruses, and treating cancer, HIV/AIDS, shingles, herpes, eye ailments and prostatitis.

However, no sound scientific studies to evaluate these health claims have been published in reputable medical journals. In fact, the Food and Drug Administration has taken action against some manufacturers of colloidal silver products for making unproven health claims.

It's not clear how much colloidal silver may be harmful, but it can build up in your body's tissues over months or years. Most commonly, this results in argyria (ahr-JIR-e-uh), a blue-gray discoloration of your skin, eyes, internal organs, nails and gums. While argyria doesn't pose a serious health problem, it can be a cosmetic nightmare because it's not reversible, even when you stop taking silver products.
Rarely, excessive doses of colloidal silver can cause possibly irreversible serious health problems, including:
Seizures and other neurological problems
Kidney damage
Skin irritation
Colloidal silver products also may interact with medications, including penicillamine, quinolones, tetracycline and thyroxine medications.

John,
I am assuming that traditional treatments were exhausted first. Other antibiotics can be less toxic and effective.
Good luck.

Gerry