We have a 5 minute suggestion for you. Install a Captcha plugin so that a bot can’t post comments on your site. You will still probably get some Spam. We still do on our sites, but it is more manageable, and we can control it so our web host doesn’t shut us down. Here’s a simple 1-2-3 on how to install this on your own WordPress site.
Go to your dashboard and under Plugins, click add a plugin. You can search for “recaptcha” or “captcha”. The one we like best is Better WordPress reCAPTCHA because it integrates well with Akismet. You can customize the appearance and location. Very user friendly.
Another hint – always check you Spam under comments and be sure to empty.