It is extreamly hard for a human to contract piscine TB.
Human Infections of Mycobacterium marinum
In humans, the two most common manifestations of this infection are a single large granuloma or an ascending lymphangitic granuloma (a series of smaller nodules usually starting on the dominant hand and progressing in a line up the arm). Less commonly seen is an infection in the joints, which will cause arthritis-type symptoms. This latter type of deep infection is associated with a puncture, like that from the spiny ray of a catfish or from a deep, open wound that becomes infected. Lastly, there is a rare case of a disseminating disease seen in immuno-compromised individuals that can be fatal.
People diagnosed with HIV or AIDS, cancer patients undergoing chemotherapy, or any other person with a known immune system problem should be particularly careful. If you fall into any one of these categories, you may want to consider hiring a service company to take care of your tank. Also note that symptoms can wait to present themselves from two weeks to four months after initial exposure, due to the slow growth rate of this bacterium. Keep a close eye on any open cuts for that same time frame to ensure they heal properly and are not subject to infection.
Taken from
http
/www.reefkeeping.com/issues/2003-07/...ature/index.php
Warning graphic pictures of infection in the link