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Pathophysiology, diagnosis, treatment, and prevention of gonorrhea

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- [Voiceover] Gonorrhea is caused by a bacterial organism called Neisseria gonorrhoeae. Now, that's kind of a long name, so it's actually more commonly referred to as gonococcus, where gono just comes from its name, and then coccus actually just means a sphere or a ball. And in fact, gonococcus has a very distinct shape, where it's like a pair of two balls that travel together, and that's, as we'll see in a minute, what the bacterium that causes gonorrhea looks like. Now, if we look at the part of the body that's mainly affected, here, in the case of the female, you'll see here's the urethra, that leads to the bladder. Here's the vagina, that leads up to the cervix and the uterus. And here's the anus, that leads up to the rectum. Let's use this picture to talk about the pathophysiology of gonococcus. The pathophysiology, or in other words, how gonococcus causes symptoms in a patient. It first starts when the gonococcus is spread into the vagina this way, and it kind of makes its way upward to infect the walls of the vagina and eventually the cervix over here. But let's take a closer look up here to see how gonococcus makes its way up here. Here you'll see a blown-up picture where you have the cervix and the walls of the vagina that lead up to it. We know that gonococcus will enter into the vagina and somehow spread its way upward. The way that works is because of these extensions that come off of the gonococcus. One of these is called a pilus, a pilus. Or if we're talking about many of these at once, they're referred to as pili, pili. The pilus will allow the gonococcus to grab onto the wall. As you'll see, there's a bunch of epithelial cells here that line the vagina. The pilus will work like a grappling hook, so it'll snap the gonococcus upwards towards the cervix, allowing it to move deeper into an infected person. So, generally, it'll go upward, but remember, the body has an immune system that's supposed to prevent the gonococcus from going further and further into an infected person. So what I've drawn here is a white blood cell. This white blood cell will look for the gonococcus and actually swallow it. You'll see a lot of these gonococcus or gonococci, that's how you say the plural version of them. Many of these gonococci will be inside the white blood cell. I'll leave off drawing the pili for now, and instead highlight this very interesting feature about gonococcus. Now remember, whenever white blood cells come and swallow up these bacteria, we're trying to process the proteins that are on these organisms so we can develop antibodies or other ways that we can attack the bacteria if they ever infect us in the future. This process of the body remembering an infection in the past and acting on it in the future is referred to as immunologic memory, immunologic memory. The interesting thing about gonococcus is that no matter what the body does, it can't develop immunologic memory against it. The reason why is because when white blood cells try and swallow the gonococcus over here, they try to latch onto them with these things, these receptors right here. These are called opa receptors, O-P-A, opa receptors. These guys help kick off the process of developing immunologic memory. The reason why they don't work on gonococcus is that they have this protein on them. I'll just draw it as like a little wedge or a triangle here. This protein, that's referred to as an opa protein, that will bind these receptors and prevent them from working, which is why every time a person is infected with gonococcus, they have to go through the process of attacking the bacteria as if it's a new type of infection all the time. Okay, so now that we know some of the tricks that gonococcus can use to infect us, what are some of the tricks that we can use to help in the diagnosis of gonorrhea? The first thing that's usually done is that a swab is taken to get a sample of the bacteria that may be infecting the patient. So when you get a better look at this swab right here, you'll see that it'll have some streaks of cells from the vaginal mucosa. There may be some mucous in there. Something that we can't see that we hope is there are some traces of the gonococcus bacteria. So in order to study it, what we need to do is take this swab and smear it on a microscope slide. When we do that and we take a look with a microscope, we can add extra stains to the microscope slide in a process that's referred to as Gram staining. We can Gram stain the slide to see what kind of organisms we have underneath there. When we look under the microscope, we might see this. This is what's referred to as a polymorphonuclear cell, or also it's known as a neutrophil. You can see three neutrophils in this slide right here. This neutrophil in particular has swallowed a ton of gonococci. I can circle a ton of them right here. So the way we would describe this Gram stain would be as Gram-negative cocci, Gram-negative cocci, which just means that the bacteria that we're seeing here are coming up as red, which refers to a negative retention or no retention of the Gram stain, as well as cocci, which just means that we're seeing spheres. A coccus just means a sphere, but there's not just one of them individually, they're in pairs. So we say that we see here Gram-negative cocci in pairs. And if you see this, it's classic for a gonorrhea infection or for gonococcus. Usually, this is all we need to do to make our diagnosis, especially with the constellation of symptoms that a patient will have. But another step we can take, and I'll draw it right here, is to take the swab and smear it on this Petri dish, so this Petri dish right here. What that allows us to do is that we'll put our swab here and we'll smear the sample we got from the patient and we'll let it grow over a few days. We may see this. This is a Petri dish that we've grown some bacteria on. We refer to this process as a culture. We've cultured the swab or the specimen that we took. What you're seeing here are colonies of the Neisseria bacterium or the gonococcus that's growing wherever there are bumps here. There are a bunch of different culture media or environments that you can grow the sample on. This one in particular, that's very specific to Neisseria organisms, is referred to as a Thayer-Martin medium. That means if you see anything grow on a Thayer-Martin medium, that's a pretty slam dunk diagnosis for some type of a Neisserial infection. So after we make our diagnosis, how are we going to treat it? Well, the mainstay of treatment for any gonorrhea infection will be antibiotics. We can actually check when we're culturing our sample for what antibiotics will work best. Say we have a certain antibiotic. We'll call it antibiotic number one here, and we'll have antibiotic number two up here. As you can see in our culture down here, antibiotic number one seem to not have any gonorrheal bacterium growing here at all, so that means it works to kill off the gonococcus. Whereas up here, antibiotic number two didn't really do a good job because we're still seeing a lot of these bumps growing or a lot of these gonococci growing. So one of the tricks we have up our sleeve here is that we can use the culture to identify specific antibiotics that work. Now what about prevention? How do we make sure that we don't spread gonorrhea from one person to another? Gonorrhea mainly lives within human hosts, so the most successful strategy, as with many infections, will be to prevent transmission. The most common way that gonorrhea is spread is through sex. That can include vaginal sex, anal sex or even oral sex. To prevent transmission from vaginal or anal sex, you have to limit the amount of direct contact that occurs during intercourse. The best way to do that would be through condoms. That can also work to prevent transmission during oral sex, but another device that works well are dental dams. Finally, the last way that you can spread gonorrhea is from a mother who's infected to her newborn during childbirth. Actually, the method of preventing transmission here is just to treat the mom, which, again, would be through using antibiotics. Because gonococcus lives predominantly in humans, by preventing the transmission of this disease, we can actually move in the direction of eradicating it all together.