Hi TE,
Don't sweat it too much...here in France they automatically give you a prescription for Brewer's Yeast with every antibiotic script and pretty much, any doctor who has had a bit of paralelle medicine training, gives you a script for probiotics and tells you to take at least one probiotic yoghurt a day while on antibiotics...Different countries, different protocols but they all basically tell you that you need the good bacteria to prevent bad bacterial over-run from happening...
I always buy the brewer's yeast, those mini bottles of probiotic yoghurt drink, other reinforced yoghurts etc...I tended to get yeast infections every time they put me on antibiotics until I did that.
Sharon