Bacterial Vaginosis after oral sex.

[Lebeau2501]

My wife has had a history of urinary tract problems. When she was a child, she had to take antibiotics quite often. She recently had 4 urethral dilations and her UTIs have become much less frequent, however, almost every time I perform oral sex on her, she gets BV. I have concerns about how the antibiotics may have weakened her immune system, but that's another topic.
My question is; does anyone know of foods/drinks/mouthwashes i can utilize that either increase or decrease the chance of an imbalance occurring in her PH? We are monogamous and I would prefer not having to resort to dental dams to prevent an infection. We both enjoy it so much and we could do it more frequently if I didn't have to worry about her PH the whole time! Please, if anyone has any suggestions, let me know.

-Eagerly hoping for a happier wife