Which bacterium causes meningococcal meningitis and can also cause bloodstream infections?

Neisseria meningitidis causes meningococcal meningitis and can also cause serious bloodstream infections.

This bacterium is a Gram-negative diplococcus, meaning it commonly appears as pairs of round cells. It can live harmlessly in the nose and throat of some people, but occasionally invades the bloodstream or the membranes surrounding the brain and spinal cord. Invasive disease can progress rapidly and requires urgent medical care.

Meningococci are classified into serogroups according to their surface capsules. Serogroups A, B, C, W, and Y are among those responsible for human disease, with their prevalence varying by region and time. Vaccines target several important serogroups. Meningococcal meningitis is different from all meningitis: viruses, other bacteria, fungi, and parasites can also inflame the meninges. Close contacts of a confirmed case may need preventive antibiotics.