It is possible.  By default, when you install, it only creates the superuser(host account).  So, that account is always there, but you can run the site with only this account, and will only have a specific admin account if you add one. 

Of course for security reasons, operating only with the host account is not ideal, as you don't want a regular admin to be able to modify your host settings.  

But I would refer to the previously posted link for Sebastian's blog.  I too think that should resolve your issue.  Although, as the article says be sure to do a db backup prior to executing any scripts.