blatter:
If the infection was related to the pee valve, maybe it was some kink in the pee valve tubing and back pressure on ascent forcing contaminated liquid back up the urethra?
As Web Monkey said, if it was from simple contamination, then lots of wetsuit divers would be in trouble all the time. My wetsuits are badly contaminated ...
Okay, I wanted to keep it up a level but here we go. Your natural equipment has a self-sealing feature. At ambient pressure like in a wetsuit, if there is nothing to artificially defeat the self sealing feature, it is only operative when there is pressure behind it, keeping contaminants from re-entering you. Ergo, wetsuit divers are not especially prone to picking up infections.
The potential problems with the pee valve are two-fold: First, some condoms defeat the self-sealing feature by pulling it open and leaving it that way (for me, this is what Rochester Wide Bands do.) In this state, any liguid in the system can contact the inside of the valve assembly including the tubing, and freely flow back into your body when there is not a pressure head behind them forcing them out.
Second, if there is a kink, the same thing happens when you try to go. You don't need back pressure "intubating" you, just free circulation in the tubing or valve through to you. Once the free flow out of the sytem has stopped, if you're still trying to go, the liquid is not flowing freely out of the sytem, it's refluxing and bringing contaminants back into your body.
Honestly, this isn't that uncommon. Talk to a group of tech/cave divers and you'll find a few who have experineced this, and it is the pee valve that's the culprit.