Just curious which specific strains can exist in beer, and if so, what are the various alcoholic thresholds for each?
Pathogens have a hard time surviving very long in finished beer let alone probiotics.
Most open fermentation bacteria (lacto, pedio) die off pretty quickly once yeasts have produced alchohol.
Further even antibiotics are adversely affected even by consuming alchohol while on them.
There are many articles on how habitually consuming a lot of alcohol can deplete the bowel of probiotics.
So I would say beer of any normal strength ABV wouldn't be a good medium for probiotics to survive in.
The low pH and hops in beer also play a big role, in inhibiting bacteria growth and survivability in beer.