What is bacterial vaginosis?

- [Voiceover] Bacterial vaginosis is a disease that's caused by the overgrowth of a type of bacteria that's called Gardnerella vaginalis, Gardnerella vaginalis. And as the name might suggest, this is the most common vaginal infection. Now I wanna put these really big quotes around the term infection because the thing that's interesting about Gardnerella vaginalis is that it's a bacteria that's naturally found in the vagina. Now some may consider this to be a sexually transmitted infection, which is interesting because it doesn't cause any problems until there's too much of it there. So when we look to the causes of bacterial vaginosis, they are all things that change the vaginal environment. That can include acts like douching, so douching, or rinsing of the vagina. The other is having new or multiple sex partners. And finally, another known cause is the use of antibiotics. This could be in the case of somebody that has a throat infection or a pneumonia that's on antibiotics which will then attack the bacteria that exists within the vagina and allow Gardnerella vaginalis to overgrow and cause bacterial vaginosis. So we've touched a little bit on it here, but I wanna draw it out. So when we talk about the pathophysiology of a disease, we're talking about the mechanism by which that disease occurs. So in order to understand the pathophysiology of bacterial vaginosis, we need to take a look at a sample of bacteria that exists in the vagina. So I'll draw out some Gardnerella vaginalis bacteria, and so I'll put this up in our key. This is the symbol for Gardnerella vaginalis. And I'll draw a few of them around here, but I also wanna show that there are a lot of other bacteria that exist in this sample. So if you really look at it here, the Gardnerella vaginalis is the vast minority of bacteria that are present in this sample of vaginal bacteria. So what happens over here, let's say our patient is somebody that's recently been treated for a throat infection, and so they're taking an antibiotic. What happens is that antibiotic kills off some of the bacteria that exists in the vagina as well as elsewhere in the body. As you can see now, the majority of bacteria that exists are the Gardnerella vaginalis bacteria. So they'll reproduce and overgrow, and if they do so, you're going to end up having bacterial vaginosis. So the key here is that you have an increase in the population of your Gardnerella vaginalis bacteria, and that leads to your symptoms. So what symptoms can you have with bacterial vaginosis? One of the main features associated with bacterial vaginosis, or BV, are copious, or a lot, of vaginal discharge. This discharge also characteristically has a fishy odor to it as well, and perhaps one of the most dangerous symptoms or effects that can occur is that pregnant women can deliver their babies early, and this is referred to as preterm labor before the baby has enough time to properly mature in the uterus. So it's important then to talk about how we can diagnose bacterial vaginosis. This is mainly done by using what's called a wet mount. So a wet mount. That's where you take a swab or a sample from the vagina, so this swab has taken a sample from the vagina, and you add this onto a microscopic slide, so right here, and when you take a look at this under a microscope, what you'll see is this. Now you've got these two simple squamous cells. So I'll label that. These are vaginal epithelial cells, both of these guys. What I'm hoping you can see littered all over these cells are just these bacterial organisms. There's just so many of them just kind of outlining them. They're just littered with them all over the place. So this is actually a clue. In fact, these are referred to as clue cells. If you find these under a wet mount, that indicates that your patient has bacterial vaginosis. Okay, so now that we've made our diagnosis, the next step, of course, would be treatment, and because Gardnerella vaginalis is a bacterium, you would treat it with antibiotics to decrease the amount of Gardnerella vaginalis that exists in the vagina to return to the normal demographic, or population, of bacteria we should have there. So the next question you can ask would be how do you prevent BV from happening in the first place? And that's a tougher question to answer because some of these things that cause BV, like using antibiotics to treat pneumonia, well we have to use antibiotics to treat pneumonia. So the only thing that's recommended to prevent when having new or multiple sex partners, use condoms. Beyond that, what doctors usually do when a patient becomes symptomatic is just to treat with antibiotics.