Well, I'm thinking thats not necessarily correct...to an extent it is
but your vet can do a deeper swab...insert it vaginally. Technically,
any swab like like isn't really "clean" in the sense of sterile but you
can tell whats normal bacteria and whats not. If you had noticed it
prior to coming in, there will still be evidence leftover. It won't be
completely gone so doing a vaginal swab will get some of whats left.
You only need a touch. Should there be anything growing that doesn't
belong, you will be able to determine it.
Let me know if you have any other questions
Good Luck &
Best Fishes