I believe all one needs is a good quality probiotic. How many 'billion' a label says it has is not so important, as the good bacteria will multiply in the gut, if you are taking this regularly and are not killing the good bacteria with antibiotics.
Ask someone at the health food store what probiotic brand has the best live probiotic. Usually what is stored in a refrigerated section is very good. Plain yogurt is very good.
There are more potent supplements, L. rhamnosus GR-1 and L. reuteri RC-14, proven to effectively rebalance the gut and reduce pathogenic bacteria and yeast and since it is effective in the female vaginal tract, it seems it may also be beneficial in overcoming a yeast infected scrotum (though you may not have that problem, I am simply stating information for whomever may read this).