Have you tried behavioral modification techniques?

Like simply not reacting to negative comments, or even changing the subject, coupled with responding positively to neutral or positive statements or topics? In other words, consistently fail to engage in the negative components of your conversations with this person.

Don't try to counteract the negativity, thus creating resistance. Simply don't engage it--deflect it. And then definitely engage in other topics or tones of conversation. Even if you agree with the negative statement, don't commiserate-don't engage in any fashion at all.

Consistency in applying reinforcements is the name of the game with behavioral modification. If you can consistently do these things, it is very likely you will begin to notice a decrease in the number of negative remarks this individual makes to you within 4 to 6 weeks. Unless other people with whom this person works do the same, the behavior will probably never be completely extinquished, but you can definitely influence how much they engage in it when working with you.

Janie