Final answer:
The frequency of infection that deems vaginal candidiasis recurrent is 4 episodes in 24 months. PCR for confirmation should be performed.
Step-by-step explanation:
The frequency of infection that deems vaginal candidiasis recurrent is 4 episodes in 24 months. In this case, PCR (Polymerase Chain Reaction) for confirmation should be performed. PCR is a molecular test that can accurately detect and identify the causative organism (Candida) in the vaginal sample.