Schwob, I'm no expert, but I would suspect I dive infrequently enough that my wetsuit remains thoroughly dry long enough--at least a few weeks--that the microorganisms dehydrate and die. I'm sure UV exposure would help, but it can also promote deterioration of the neoprene. That's why wetsuit manufacturers advise drying in the shade. The more frequently I dive, the more attention I would pay to disinfecting. But I don't THINK I presently dive often enough for this to be an issue. Anyone with a more scientific perspective?
Cleaning and disinfecting it well and letting it air dry completely should provide adequate protection. Some bacteria produce spores that allow them to survive for long periods in harsh conditions, but these are not generally associated with diseases of the upper layers of the skin (but they can cause infections and gangrene in puncture wounds.)
Molds also produce spores and some molds cause skin diseases like Ringworm and Athlete's Foot that can be very difficult to treat and eradicate. Yeast is also a fungus and it can be hard to kill, but keeping your skin and your equipment clean and dry should be sufficient. Nothing is 100% and that's not just true for diving. You just have to be mindful and careful and seek treatment right away if something starts to develop.
One of the nice things about being on a liveaboard is not wearing shoes for a week, but once during a LOB trip in the Caribbean I got a really bad infection in the little toe of the right foot. I wasn't too concerned at first but it quickly got very nasty. My toe got red and swelled up and was very painful and I couldn't wear my booties. I was starting to think that I was going to have to go to the Captain and say "I need medical treatment, I have to get back to shore because my toe hurts!"
But I raided the First Aid drawer and kit, and took good care to keep the infected area clean, dry, and I treated it with topical antimicrobial ointment after every dive. And I wore shoes and socks when not diving. The infection got a lot better and I was able to keep diving but it didn't heal completely. I saw the doctor as soon as possible after we got home and the problem was ultimately identified as a combination bacterial and fungal infection and very hard to treat. It took several visits to the doctor and rigorous treatment after I got home before it finally disappeared.
I cleaned and disinfected my booties extra well after that trip and made sure that they were completely dry, and I have not had any reoccurrence of the infection on subsequent trips, but I am now very careful to keep my feet clean and dry - and I carry anti-microbial ointment and bandages with me on dive vacations! And I often put on dry scuba socks before getting in to my booties.