My DD says that there never has been any scientific studies done. I am, however, more than willing to listen to any of the many SPNG devotees on this board who may be aware of something i haven't been able to dig up. That shouldn't be too hard to do. Something as integral to the product as a scientific claim should have supporting documentation. After all, that claim is an important part of what sets this sponge apart from others on the market.
In as much as you have some medical training, I think you would agree that nobody but the basest of charlatans would claim health benefits for their product when none in fact exist. So, I'm sure the scientific back up for the "anti bacterial qualities" must be there, I hope. But, i have not found them. Are you aware of any studies/ could you provide a link?