Heres a article i found interesting in today's news.
http://news.discovery.com/animals/sh...mkcpgn=rssnws1
* Teeth aren't a shark's only weapon; they also harbor deadly, drug-resistant bacteria.
* Despite the findings there have been no reported cases of shark-related bacterial infection.
* Scientists warn other marine creatures likely harbor drug resistant bacteria as well
Mostly what I discovered was that the cause may of been improper disposal of anti-bacteria.
As a side note, I learned along time back that you should boil your waste water from your tank before disposing of it down the drain if you use antibiotics.
However such a pain this would be, I myself have never done it either, so mostly just be very careful what meds you treat your tank with, they do end up in the ocean eventually.