
I wonder why, if you had swabs done, and presumably then culture and identification so you got the right treatment, your vet hasn't sorted all this out! If we had a stubborn problem with ears, this is what we did - there is no point putting 'moisture' down the ears if it's the wrong kind as it only makes a nice breeding ground down there.
End of the day if nothing works, you may be looking at having an aural resection done - where a small nick is made immediately under the ear, to allow more drainage/air to get to the cavity.
http://www.michigananimalhospital.com/page/490551594I'm afraid this is back to the vet because if this isn't sorted out, it may well affect the inner ear, which has it's own problems!!