Spam links appearing on my site

Every so often I see a single random spam link appear in the top left corner of my navigation menu. The screenshot below shows where it appears in the code as well, in case that helps.

Normally when I do the necessary updates to WordPress and my plugins, it fixes the problem – however my latest attempt at this, which updated 2 plugins, did not fix the problem.

However the last update I did worked in getting rid of the spam link, and it updated only those same two plugins along with several themes I’m not using.

Any ideas as to what could be causing it this time, and how to get rid of it? I tried clearing my cache multiple times so I assume this is not just on my machine…

http://i15.photobucket.com/albums/a386/bullockstroy/wp-screenshot-1.jpg

http://luxespachicago.com/