Neisseria meningitidis

Hello, everyone. My name is Dr. Sara Fouch. Within this short recording, we will be considering the organism Neisseria meningitidis, the clinical condition that this organism is most associated with, and the virulence factors it can produce to make it such a successful pathogen.

Now, Neisseria meningitidis, as the name suggests, is associated with meningitis. We've known about this organism since the early 19th century. The causative organism was described in 1884, and it was isolated in 1887 in six patients. These are patients who had meningitis-like symptoms. Since this time, there have been multiple outbreaks. If we think about 1941, there was an outbreak in a military barracks, and this forced the attention and focus the attention to the various factors of Neisseria meningitidis and the virulence factors in particular, why this organism was associated with meningitis. You might be thinking to yourself, why on Earth is she talking about 1941? But this outbreak really did force attention to this organism. Now, obviously, we now have a vaccination for meningitis, so we're starting to see the number of cases of meningitis reduce, which is a positive thing. However, the vaccine isn't readily available across the world. It's important to think about meningitis, not only here within the UK but also worldwide. Now, this is an encapsulated Gram-negative diplococci. They look pretty much identical to Neisseria gonorrhea. But again, we've got some similarities with both Neisseria gonorrhea and also Haemophilus influenzae. But that capsule helps to protect the bacteria. That capsule is a key virulence factor. Now, interestingly, we carry Neisseria meningitidis in very low numbers in our oral pharynx. But it can easily go on to cause serious disease. We need to think about why some patients can just carry Neisseria meningitidis and why some might go on to have a condition that can progress rapidly. If the patient doesn't get treatment, then actually they will decline quite quickly. When we think about the serogroups or the serotypes, there are 13. But the most common ones are A, B, C, W-135, X, and Y. Now, Group A is mostly seen in drier climates, commonly in Africa and Asia. Group C, W-135, and X are associated with epidemics. Again, we've seen epidemics in Africa. Group A belongs to a single serotype, while Groups B and C belong to multiple serotypes. We have worldwide occurrence, so it's not a condition that just affects one area of the world. Now, when we think about how we transfer