Motile via flagella at 30 °C and below, but usually not at 37 °C,[4] L. monocytogenes can instead move within eukaryotic cells by explosive polymerization of actin filaments (known as comet tails or actin rockets).

Seven serotypes of the bacterium have been identified on the basis of capsular polysaccharides. H. influenzae type b is the most important serotype involved in meningitis.

We found that possession of a capsule was essential for causing meningitis.

These capsular polysaccharides protect the meningococci from the action of phagocytic cells and enhance organism’s survival during bloodstream and Central Nervous system invasion.

More than 98% of cases of invasive meningococcal disease in the United States are sporadic. In 2008 in the United States, disease caused by serogroup B (32% of cases), serogroup C (32% of cases), and serogroup Y (24% of cases) accounted for most of the endemic disease, causing meningitis in 53% of cases

S. pneumoniae is now the most common etiological agent of bacterial meningitis in the United States and Europe, accounting for 61% of total cases in the United States

it now accounts for only 7% of cases (281, 305).

Prior to the availability of H. influenzae type b conjugate vaccines in the United States, H. influenzae accounted for 45 to 48% of all cases of bacterial meningitis

Given the better system of searching for active cases, the overall incidence of bacterial meningitis was two to three times that of the previous report (276), although H. influenzae, N. meningitidis, and S. pneumoniae continued to account for the majority of cases (77%).

ow CSF white cell count and elevated CSF opening pressure are also associated with a poor outcome. Mortality in non-HIV-associated cryptococcal meningitis is associated with chronic renal failure, liver failure, or hematologic malignancy, as well as absence of headache and altered mental status. [51]

encapsulated bacterium.

hough H. influenzae meningitis is rare in adolescents and adults, rates of meningitis due to Hib are highest in children less than five years of age, with an estimated incidence rate of 31 cases per 100,000

including hearing loss, developmental disorders, and neuropsychological impairment are reported to occur in up to half of survivors of bacterial meningitis.

case-fatality rates of 30% and 7% in higher-income countries

On the basis of ABCs data, the serogroup distribution in the US in 2007 was serogroup B, 25%; serogroup C, 30%; and serogroup Y, 37%, with 9% caused by serogroup W-135, other serogroups, and nongroupable strains (www.cdc.gov/ncidod/DBMD/abcs/survreports/mening07.pdf).

Virulent N. meningitidis strains have a polysaccharide capsule, which allows the organism to cause invasive diseases such as bacteremia and meningitis.

On average, bacterial meningitis caused about 4,100 cases and 500 deaths in the United States each year between 2003 and 2007.

Symptoms of bacterial meningitis can appear quickly or over several days. Typically they develop within 3 to 7 days after exposure

How people spread the germs often depends on the type of bacteria. It is also important to know that people can carry these bacteria in or on their bodies without being sick. These people are “carriers.” Most carriers never become sick, but can still spread the bacteria to others.

Neisseria meningitidis, Streptococcus pneumoniae

Viral infections are the most common cause of meningitis, followed by bacterial infections and, rarely, fungal infections.