What Causes Foul Smelling Buttocks After Treated Jock Itch?

I recently had jock itch and are now getting over the symptoms for the most part, but since I have had it four weeks ago I seem to get a fishy rectum smell even while showering. Its on and off that I smell it, but this hasn't occured since I got jock itch. I shower twice day mostly every day of the week and I recently have noticed my eatting habbits were extreamly poor these past months. What could this be from and am I at risk? I have been very sexually active but I wear condoms. Not with all my partners but we all get check ups regularly so we know what's going on with our bodies. That includes std/aids check up all saying negative. What's going on with this smell?