Interestingly i see that a recent (2018) study shows that taking probiotics to recover from from antibiotic treatment could actually be counter intuitive... gah....theres never any clear answers is there..
Basically the prevleance of a few strains of good bacteria that you have supplemented hinders the ability of other healthy strains to get a foothold. People who didnt take prebitoics recovered normal gut flora in 3 weeks, people that supplemented with probitoics hadnt recovered within the 6 month trial!