Stoeckel- Neisseria Flashcards
Neisseria is the only genus of ____________ to frequently cause disease
Gram-negative cocci
Neisseria is an obligate ______ pathogen
human
cannot survive without host
what are the 2 main Neisseria species?
A) N. meningitidis
B) N. gonorrhoeae
what are the important virulence factors for N. gonorrhoeae?
A) no capsule
B) STRONG adhesins
C) phase/antigenic variation
________ are usually diplococci
N. gonorrhoeae
the Human _______ is the only reservoir for N. meningitidis
nasopharynx
Meningococci invade what?
invade mucous membranes of nasopharynx
type ____ pili allow meningococci to attach to the host’s CNS
type 4 pili
what aspect of meningococci causes damage to the host tissue?
the Lipooligosacccharide (LOS)
How does Gonococci enter its host?
attaches to columnar epithelia of cervix or urethra
the Adhesins of gonococci are controlled by what?
A) Phase variation
-presence/absence
B) Antigenic variation
-composition
what is phase variation in E. coli?
expression of gene product gets turned on/off at high frequency
“strobe light” genes
N. gonorrhoeae- Phase variation
Slipped strand mispairing
A) Colony opacity-associated genes (Opa genes)
-encode outer membrane proteins
what is Opa? what does its presence result in?
Opa = opacity-associated genes
Opa’s presence results in neutrophil uptake
antigenic variation in N. gonorrhoeae changes in composition or structure of _________
surface molecules (pili)
T/f: gonococci multiply rapidly
true
Gonococci lack ______, which means they are not mobile
flagella
how does the extracellular protease of Gonococci enable it to “hide” from phagocytosis?
it cleaves IgA1
removes Fc-receptor end of antibody
what microbes can cleave IgA1?
Gonococci
Haemophilus
(and streptococci)
Gonococci attach to _______ cells
non-ciliated cells
A) fallopian tubes, columnar epithelium
what role does ciliary stasis play in the spread/mult of gonococci?
host cell ciliated mobility slows then ceases
-prevents host cells from moving gonococci out of body
when ciliated cells die, they _____ from epithelial surfaces. this is caused by what?
slough from epithelial surfaces
caused by LPS and peptidoglycans
how are gonococci “internalized”?
non-ciliated microvilli engulf bactera
internalized by “parasite directed endocytosis”
Gonococci may multiply within ________ during intracellular replication. these _______ fuse with the basement membrane of the host
Vacuoles
Vacuoles discharge the gonococci into what layer?
sub-epithelial connective tissue
T/F: gonococci produce exotoxins
false
what causes the damage associated with gonococci? what is the effect?
LPS (LOS) of the gonococci
- triggers release of TNF-alpha
- sloughing of ciliated cells
- non-ciliated cells lyse
how does Neisseria evade LPS recognition from the host body?
alter LPS with host-derived sialic acid
-sialic acid is part of red blood cells
LOS (lipooligosaccharides) are similar to antigens on human ________
erythrocytes
allows evasion from host immune system
what is the main virulence factor differences between meningococci and gonococci?
Meningococci heavily encapsulated (polysaccharide)
and produces hemolysin
what is PID? what causes it?
Pelvic inflammatory disease
Gonococcal infection of female upper reproductive tract
what is Epididymitis?
Ascent of gonococci into upper reproductive tract of men
Disseminated gonococcal infections (DGI): what are its symptoms
A) inflammation of tendons and joints
B) suppurative arthritis
C) can result from PID (endotoxin release)
Purpura Fulminans is caused by which microbe?
Meningococcus
causes coagulation in small blood vessels
Disseminated intravascular coagulation (DIC) is caused by what? what are its effects?
caused by Meningococcus
causes meningitis, shock, death
what dictates the damage and risk of death from Purpura Fulminans?
higher the host response = greater damage/risk
Most Neisseria are resistant to which antibiotics?
A) Penicillin
B) tetracycline
C) most other antibiotics
T/F: vaccines are not available for gonococci or meningococci
False: vaccines available for meningococci. none available for gonococci
why are vaccines for gonococci difficult to make?
Antigenic and phase variation of N. Gonococci
Adhesin production in Gonococci is controlled by what?
- Phase variation
- Antigenic variation
N. meningitidis has outer membranes and pili similar to what other bacteria?
Haemophilus
