I can't get the text of this article...but the title is kinda odd.
http://www.springerlink.com/content/q3286742tqw450k3/
I hope this one goes thru....might be worth looking at. I do not know if it is the same kind of Bartonella. This is a big problem with NOT culturing wounds.
At minimum, it sounds like a cellulitis may have been possible, and an autoimmune problem ensued. Then again, with diabetes, for is it 10 years? (if memory serves me correctly) It could be small fiber neuropathy.
Also, I had small fiber neuropathy for probably a decade before I figured out what was going on, because, I had no reason to even remotely consider that I could have small fiber neuropathy. My feet never really 'burned'. I had no concept that issues all over my body were related to small fiber neuropathy. (For example, I had no concept I was globally anhidrotic).
I agree if that cat is around, I would have him/her tested for all kinds of organisms. That said, what was on kitty's claw, may be long gone...and it is possible that kitty had no part in it at all.