Canadians - Can anyone recommend a probiotic?

Poor Squeak is on a second round of antibiotics for a UTI that's recurred and has been having diarrhea since we started this round. We've switched to a different type of antibiotic in the hopes that she'll improve, but it's only been a couple of days. I'd like to give her some extra support by giving her a probiotic, but I'm not sure what's good to give and would be available in Canada. I've searched the board for recommendations, but a lot of the products recommended either have to be imported or, if they are available, have significantly different ingredients from their U.S. counterparts.

I did get FortiFlora from the vet and gave it a try, but it seems that something in it doesn't agree with Squeak's system. She has some GI issues (food allergy? IBD? Not sure yet.), so I'll have to be cautious with what I give and start off slow.

So, if anyone has any recommendations on probiotics (and where you purchased them), I'm all ears. Thanks!