Neisseria Flashcards
Feature of meningococcus
Gram neg diplococci,kidney shaped, form polymers
aerobic
oxidase Positive Purple
What gives children partial immunity against meningococcus?
They are colonised by n lactamica
Culture of meningococcus
Grows on chocolate agar
transparent grey glistening, convex
How can the species of meningococcus be determined?
Carb fermentation / utilisation test
- metabolise glucose and maltose to acid
- does NOT metabolise sucrose and lactose
Which serogroups of meningzccus are pathogenic?
A, B, C, Y, W-135
What is in the cell wall of meningococcus
Lipooligosaccharide ( LOS )
List the 6 virulence factors of meningococcus
1 polysaccharide capsule 2 pili 3 IgA1 protease 4 Outer membrane proteins 5 Lipooligosaccharide 6 Iron-aquisition system
What does LOS do
cytokine production + alternative complement pathways
tiggers inflammatory response
What is the natural reservoir for meningococcus
Human
colonises nasopharynx
What does meningococcus release in the blood?
blebs containing
LOS -> endotoxaemia
OMP
capsular polysaccharides
Is meningococcus spread by droplet or aerosols?
Droplets
Dominant serogroup in Europe and America
B and C
Y is most dominant in North America
Dominant serogroup in Asia and Africa
A and C
Which serogroup was responsible for the 2000 outbreak in pilgrims
W-135
What is the most common infectious cause of death in children and young people up to the age of 20
Meningococcus
Age group at highest risk of infection w Meningococcus
baby <1yr
Which serogroup of meningococcus is most common in kids <6yrs
B ( for the babies)
C is more common in adolescents
Characteristics of meningococcaemia
abrupt onset
petechiae
high fever, chills, hypotension, headache
bilateral haemorrhage of the adrenals - Waterhouse Friedrichsen
What is the treatment for Meningococcal infection?
Benzylpenicillin
3rd gen cephalosporin
chloramphenicol
What are the options for chemoprophylaxis in close contacts of meningococcus
rifampicin
ceftriaxone
ciprofloxacin
Meningococcal polysaccharide vaccine
effective against A,C,Y, W135
not effective in kids under 2
has no long term memory - only lasts 3-5yrs
Meningococcal C conjugate vaccine
Works in under 2yo
long term protection
