Review Question - QID 106716

This patient has meningococcal meningitis, which is cause by Neisseria meningitidis. Neisseria meningitidis uses pili to adhere to epithelial cells in the nasopharynx.

N. meningitidis is a Gram-negative diplococci, which is a common cause of bacterial meningitis in adults, particularly in college students living in dormitories and in military recruits living in barracks. N. meningitidis is transmitted via respiratory secretions. The organism can colonize the nasopharynx of asymptomatic carriers through the use of its pili. The organism can also cause disseminated meningococcemia, which can present with hemorrhage, petechial rash, and sepsis.

Kimmel discusses meningococcal menigitis, which can result in severe permanent neurological morbidity or rapid death. In suspected cases, treatment must be initiated immediately, as the risk of death rapidly rises with any delay. Young adults age 15-24 have the highest incidence of the disease. The classic triad of fever, nuchal rigidity, and altered mental status is not seen in all patients, and diagnosis ultimately requires lumbar puncture. There is an FDA approved vaccine which targets several serogroups of N. meningitidis.

Coureuil et al. discuss the pathogenic mechanisms of N. meningitidis. N. meningitidis is one of very few organisms that is able to penetrate into the subarachnoid space. N. meningitidis accomplishes this by using its pili to mediate interaction with endothelial cells in the brain. As a result, microcolonies form, and a host cellular pathway is activated that resembles the pathway used by leukocytes to cross the endothelial surface. Consequently, intercellular junction components are recruited to open tight junctions, allowing passage of the organisms.

Figure A is a Gram stain of N. meningitidis. The video demonstrates Brudzinski's sign, which is a clinical finding classically associated with meningitis. Note that Brudzinski's sign has an extremely low sensitivity for diagnosing meningeal irritation.

Incorrect Answers:
Answer 1: Lipooligosaccharide is an endotoxin that causes septic shock, but is not important for adherence to the nasopharynx.
Answer 3: The capsule of N. meningitidis is important in resisting phagocytosis, but not in adherence to the nasopharynx.
Answer 4: N. meningitidis is not a spore forming organism.
Answer 5: Certain bacteria can form biofilms via their glycocalyx to evade phagocytosis; however, N. meningitidis does not posses this virulence factor.