I use something called Anti-Spam instead of Akismet. I think it does a better job.

Hi In addition to akismet - Kyle also recommends to install this plusin SI CAPTCHA Anti-Spam
I have the two and no issue with spam.
I hope this helps
Victoria

I had the same problem. I thought that simply activating the plugin would work. Perhaps you already have but here is a video tutorial by Kyle for setting up Akismet, if you haven't done so. Once you have done I would still check the spam folder. I have found a few comments in the spam that should't have went there. Hope this helps. How to Install Akismet - Protect Your Website From Spam