Have you tried Fast Tract? Heaps of BB members found that it got rid of thrush when nothing else did. Also if baby does have it, its completely safe for baby to take - 1ml - as it's organic. Its MUCH better than the other pro-biotics out there, firstly it contains around 13 strains of probiotics, not one or two, and its super potent.

https://www.bellybelly.com.au/misc/mivitality-inliven

(main site is currently being restarted, so down for a bit)