Nelson - Ch. 191 Neisseria meningitides Flashcards
N. meningitides is a commensal of the human nasopharynx in approx ___% of the population and rarely enters the bloodtsream
10
N. meningitides ? capsule ? oxidase ? aerobic
Encapsulated, oxidase-positive, aerobic
Differences in the chemistry of the capsule of N. meningitides allows definition of ___ serologically distinct meningococcal capsular groups
13
These capsular groups of N. meningitides are responsible for almost all cases of disease
A, B, C, W, X, and Y
Meningococci are transmitted how
1) Close contact via aerosol droplets 2) Exposure to respiratory secretions
Carriage of N. meningitides peaks during
Adolescence and young adulthood, rare in early childhood
Highest rate of meningococcal disease occurs in what age group
Infants younger than 1 year old
The “meningitis belt” is found where
Across sub-Saharan Africa
First step in either carriage or invasive disease by N. meningitidis
Colonization of the nasopharynx
Disease with N. meningitides infection usually occurs ___ after acquisition of the pathogen
1-14 days
Initial contact of meningococci with host epithelial cells is mediated by
Pili
N. meningitides pili may interact with the host ___ or ___ mediating disease
CD46 molecule or and integrin
___ secreted by invasive N. meningitides degrades secretory IgA on the mucosal surface, circumventing this first-line host defense mechanism
IgA1 protease
___ plays a significant role in rapid clinical deterioration, longer hospitalization, and risk of death in N. meningitides sepsis
Bacterial load
Resistance to complement-mediated lysis and phagocytosis of N. meningitides is largely mediated by
1) Polysaccharide capsule 2) LPS