Some advice:
1. Be sure to actually ban the spammers and not just blank out their spam. For example, http://kodi.wiki/view/User:Tainghecr3
2. Read my guide on account requests. Do not accept accounts when the “reason” given is generic and not kodi-specific: Help:Confirming_accounts (wiki)
Especially when they say things like “I’m a programmer” or a “web designer” but don’t actually answer the question of “why you want to edit the wiki”. The original question for the request account extension is “biography”, so if people answer the “why do you want to edit” question with biographical info then they’re probably a spammer. There’s a list of examples, and the logs show past rejections that I’ve done with more examples of what to watch out for.
As I’ve previously mentioned, they’ve been getting more clever. So if they do sneak past and do some mass spam then don’t panic. It’s fairly easy to clean up using the rollback link when looking at the user contribs page. For example: http://kodi.wiki/view/Special:Contributions/Ned_Scott . Admins should see a “rollback link”. Actually, all autoconfirmed users should see that, as rollback is just a shortcut and not special access, but I probably just forgot to change the default for rollback settings.
If they really get messy then there’s even some “Gadgets” that admins can install (through the web interface by editing the right wiki pages) that will help further semi-automate spam cleanup: https://en.wikipedia.org/wiki/Special:Gadgets .