Chapter 14-15 Neisseria and Bacteroides Flashcards
(47 cards)
describe neisseria spp
-gram negative diplococci
- lipooligosaccharide: lacks O antigen extensions
where is neisseria spp found
common oral flora and other mucous membranes
what pathogens are neisseria spp
n. gonorrhoeae and n meningitis
what is the only host for neisseria
humans
what are the virulence factors of N. gonorrhoeae
-pili
-antigenic variation
-OPA
-IgA protease
-endotoxin/LOS
is there a vaccine for n gonorrhoaea
no
is there a capsule around N gonorrhoeae
no
why do gonococci at different infection sites express different pilin genes
because they adhere to different cell surface receptors on distinct mucosal epithelial cells
describe the antigenic variation of bacterial surface proteins in neisseria
- PilE single chromosomal copy of pilin
- strains contain 10-15 copies of PilE variants lacking promoter and 5’end of gene called PilS genes
-PilS genes recombine with PilE creating unlimited antigenic variants of PilE
what is phase variaition of gonorrhea
on/off switch for surface protein expression
- slipped strand mispairing resulting from presence of multiple identical repeated sequences at 5’ end of gene. replication errors due to strans misalignment creates reading frame errors
- results in on/off switch
what do pili do
mediate bacterial attachment to non-ciliated epithelial bacteria proliferate and shed into secretions
what does IgA protease do
cleaves IgA
what do serum resistance virulent strains cause
disseminated gonococcal infections
how do serum resistant virulent strains cause disseminated gonococcal infections
- strains lack Opa proteins so neutrophils cant engulf bacteria lacking Opa proteins
- sialic acid on LOS binds complement regualtory proteins, prevents complement based phagocytosis
what are the virulence factors for N gonorrhoeae
- pili
- IgA protease
- serum resistant virulent strains
- shedding on endotoxin
- secretion of pro inflammatory cytokines
what are the symptoms of gonorrheal disease
asymptomatic generally
- urethritis in men, urethral pus secretion
- cervicitis in women, urination sensitivity
what is opthalmis neonatorum and how is it treated
- destructive eye infection acquired during birth from gonorrheal disease
- application of erythromycin ointment into both eyes
what is pelvic inflammatory disease and cause
-cause: infection of ccervix, fallopian tubes, and vaginal wall glands
- gonococci enter abdominal cavity causes liver disease
- tissue scarring causes fallopian tube abnormalities which lead to ectopic pregnancies and sterility
what is uretheral and testicular tube scarring caused by and what does it lead to
caused by epididymitis
- leads to sterility and increased urethral infections by other microbes
what does disseminated gonococcal infection cause
skin lesions, suppurative arthritis of a major joint, heart valve destruction
is there any protective immuity after recovery from N gonorrhoeae
no
what percentage of healthy people are carriers for neisseria meningitis
10%
how is neisseria meningitis transferred
sputum
what are the factors affecting the survivial of neisseria meningitidis
-capsule
- acquisition of iron from transferrin
