Having had two major surgeries due to "unkillable" intestinal infection, I can advocate for the efficacy of VSL#3. My GI actually prescribed me a high-dose version post-op, and two years later i can say it has been life-changing. Other common "store shelf" probiotics are not the same for whatever reason (supply-chain refrigeration and cost might explain that somewhat).

My understanding is that Visbiome is also thought to be a comparable product that has the same formulation.