What is the risk of c diff with clindamycin vaginal route since its absorption rate is 5%?

Unlikely: you are less likely to get an intestinal infection if you are receiving clindamycin via vaginal route than if you were to receive clindamycin orally or via IV. not everyone will get an intestinal infection with antibiotics, you are more likely if you are immunosuppressed or do not have a good diet, resulting in the ability for bad bacteria to grow in your gut, such as C. difficile.

Unlikely: with vaginal use since it is not in the GI tract.