I think the doctors are being a little overcautious there.  Candida
albicans is everywhere, especially in a NICU with all the antibiotic
use.  Thrush, the infection, is gone when you do not see any more
white patches, but this does not mean that there is no Candida
albicans in the baby's mouth, or on the end of his indwelling
catheter, or in his diaper area, or on the physicians hands.

Jack Newman, MD, FRCPC