Question: Cunnilingus used to be a regular part of the sex life my girlfriend and I enjoy, until we ran into a problem. Literally one out of three sessions resulted in a bladder infection for her, requiring antibiotic treatment, bed rest, frequent bathroom visits and lots of back massages. It got even more serious with the last infection, which lasted over a week and was probably an indication that she has become immune to the antibiotics. For now we’ve removed cunnilingus from our habits, but I at least would like to be able to bring it back with little to no risk of bladder infections. Are there any tips that you have for reducing the chances of an infection? Two methods that I’ve thought of are a) gargling with an antibiotic mouthwash (Listerine) before oral sex b) making sure she lets herself ejaculate during orgasm, to flush out any bacteria trying to sneak in. Any help would be appreciated on this issue.

Answer: Have you given some thought to the idea that you are infecting your girlfriend? You may have bacteria present in your mouth that is harmful to her. Please go with her to the doctor and discuss having them culture your mouth for infectious bacteria. It is possible, for example, that a man has yeast in his mouth and as a result keeps re-infecting his partner.

It is a good idea to have her urinate prior too and immediately after any sexual activity involving her vulva and vagina, given her current medical history. She should also drink plenty of water and some cranberry juice as its acidic level kills the bacteria that commonly cause urinary tract infections.

You can use plain old plastic wrap, the type you use in the kitchen, as a barrier between her vulva and your mouth. Just cover her entire vulva with a single layer and do as you normally do. You can also buy dental dams from places that sell condoms, at least on-line.

Followup E-Mail 1: I guess I should have been more clear in my first message, we both knew that the infection was coming from my saliva during oral sex. Luckily, we have found a method that's worked so far. To eliminate the current infection and prevent any relapses, my girlfriend took a prophylactic antibiotic for about a week that definitely cured the current infection and there's been no sign of another. Thank you for your suggestions on the problem, although I would suggest changing cranberry juice to cranberry supplements, as the juice contains a good amount of sugar that can worsen the infection.

Followup E-Mail 2: Your first assumption was right, it was bacteria in my saliva (some strain of E. Coli to be precise) that was causing the infection. Saliva itself (sans impurities) is a pretty sterile fluid that in fact coats most micro-organisms to prevent them from infecting us or others.

Followup E-Mail 3: An antibiotic wouldn't have really helped, as everyone has some E. Coli living in their mouth, it's just that we're immune to the strains we host. However when this bacteria comes in contact with someone who is not immune or a prone part of your body (open wounds, urethral opening) it can cause an infection. Basically, the E. Coli strain that infected my girlfriend is most likely still living in my mouth, but it poses little risk because a) my girlfriend is mostly or totally immune to it after the infection b) if we anticipate oral sex, she can choose to take an antibiotic pill as a pre-emptive cure. Please also keep in mind that the average woman won't be nearly as prone to bladder infection, my girlfriend's female relatives (mother included) all have a history of bladder infections. If you have any other questions, feel free to send them this way, I pretty much researched bladder infections as much as possible to find some type of solution :)