H.R.
Activated (a.k.a. medicinal) charcoal can help clear up infection quickly (this is not the same thing as artists charcoal or fireplace soot). It has been used for centuries as an alternative medicine. Visit the following website: www.buyactivatedcharcoal.com They have medicinal charcoal (look for colic calm for infants or activated charcoal powder-finely ground). They are also very helpful and would be happy to give advice if you prefer to consult them prior to purchasing. You can mix 1 Tablespoon in 8oz. water and have him drink it (you may need to let it settle and have him drink the "gray" water off the top), or you can apply an external poultice using ground flax meal, water, and charcoal powder several times until you see the infection begin to clear. Activated charcoal, may help prevent the infections.
As for other prevention methods... make sure that the bottles/sippy cups you are using are being sterilized between each use (this also goes for your breasts if you are still breast feading - bacteria such as Staphylococcus and yeasts/fungus such as Candida are naturally present on human skin and may be contributing to the problem). Don't let feeding instruments or pacifiers sit out for long periods of time without being washed, they will begin to breed bacteria quickly. You may find it helpful to follow each drink/meal with a good "mouth washing", either have him drink 6-10oz. or if possible rinse well with straight water following feeding/drinking.
You may also consider that he might be allergic to the milk you are giving him which could be triggering this infection. If his is old enough to be taken off milk/formula it may be well worth it. If he is still taking a bottle/pacifier you may want to wean him off it... the suckling process itself could be at the root of the problem.
Best wishes to you both!