Interesting article. Will have to read more about it in the literature. The mouthful of water reference sounds alarming, but it doesn't clarify which are bad bacteria and good bacteria. When people are on penicillin for long periods of time, this rids their body of all bacteria, good and bad and they have to take capsules containing good bacteria to bring the good bacteria levels back to acceptable limits.
It will certainly enter my mind when swimming in the ocean.
Thanks for sharing the article.