I came home from Mexico five years ago with salmonella, e-coli, and a third one I can't remember. The result is a totally screwed up GI system, so I take probiotics "as needed" now, usually every few months when I start getting belly aches, then I take a month or two course of them to set things right. I read everything I could find, tried following recommendations, tried several kinds, but after a while realized it was like trying to figure out which brand of anything is better than the other.

What works for me is the Phillips Colon Health brand. It's not cheap but I know it works since the awful stomach aches stop.

Hope you find something that works well for you.