Neisseria, haemophilus, pseudomonas and Listeria

Question 1

Neisseria traits

Answer 1

only gram - cocci that frequently cause disease
non-motile
aerobes
OBLIGATE human path
FASTIDIOUS

Question 2

diagnosis of neisseria

Answer 2

cultured on chocolate agar
catalase and oxidase +
sugar fermentations
modified Thayer-Martin agar

Question 3

main neisseria sp.

Answer 3

meningitidis and gonorrhoeae

Question 4

virulence factors of neisseria sp.

Answer 4

meningitidis : large CAPSULE

gonorrhoeae : strong adhesins and PHASE/ANTIGENIC variation

Question 5

how do meningococci invade/cause damage?

Answer 5

enter thru nasopharnx and attach to COLUMNAR ep cells
only cause bacterimia in folks w/ C5-8 complement deficiency
type IV pili attach bact to meninges in CNS
lipooligosaccharide causes inflammatory resp damaging host tiss

Question 6

how do gonococci enter/attach

Answer 6

apread thru body fluid
attach to columnar ep of cervix/urethra
has adhisins which are controlled by phase variation (!!) and antigenic variation

Question 7

how does gonorrhoeae phase variation work?!?

Answer 7

Opa genes encode membrane prot. and have slipped strand mispairing so they’re always making diff prot.
Opa genes result in neutrophil uptake but gonococci don’t have them and avoid phagocytosis
makes it hard to vaccinate

Question 8

how do gonococci spread and multiply?!?

Answer 8

multiply rapidly and are shed in genital secretions
enter ep. cells
avoid phagocytosis by removing Fc- receptor end of IgA antibody (!!)

Question 9

how do gonococci invade tissue?

Answer 9

attach to non-ciliated so they slow and kill ciliated cells
then cause non-ciliated cells to endocytose them so they can multiply w/in the vacules
vacuoles discharge bact into subep. connective tiss

Question 10

how do gonococci cause damage?

Answer 10

LPS (endotoxin)

induce TNF-alpha

Question 11

how do gonococci evade antibody recognition?

Answer 11

antibodies target the LPS but gonococci can alter it to look more like a red blood cell

Question 12

3 diseases of menigococci

Answer 12

1 uncomplicated becteremic

2. metastatic infection of meninges
3. systemic infection causing cirulatory collapse and disseminated intravascular coagulation

Question 13

what is pelvic inflammatory disease?

Answer 13

gonococcal infection of upper female reproductive tract (b/c ciliated cells) and epididymis in men

Question 14

symptoms of disseminated gonococcal infections

Answer 14

pelvic inflammatory disease
pustular lesions of skin
inflammation of tendons/joints
suppurative arthritis
risk factor= women

Question 15

treatment for neisseria

Answer 15

penicillin/tetracycline resistant

antimicrobial chemoprophalaxis

Question 16

why is it hard to vaccinate for gonococci?

Answer 16

phase and antigenic variation and protective intracellular components

Question 17

traits of haemophilus

Answer 17

sm gram - coccobacilli
aerobic
colonize upper respiratory tract

Question 18

what does H. influenzae require for growth?!?

Answer 18

HEMIN (X factor) and NAD+ (V factor)

Question 19

haemophilus diseases

Answer 19

influenzae - bacteremia and meningitis
parainfluenzae - pneumonia and endocarditis
ducreyi - chancroid
aphrophilus - normal flora
aegyptius - conjunctivitis and brazilian purpuic fever

Question 20

haemophilus VIRULENCE FACTORS ?!?

Answer 20

POLYRIBOSYL RIBITOL PHOSPHATE (PRP) - basis for vaccine, causes resistance to phagocytosis (makes HiB most virulent
endotoxin
IgA protease, pili and OM proteins (like nisseria)

Question 21

how/why are children immunized for haemophilus?

Answer 21

get PRP conjugated diptheria toxoid b/c they’re most succeptible

Question 22

best treatments for haemophilus?

Answer 22

3rd gen cephalosporins b/c they penetrate menines

and chloramphenicol

Question 23

traits of pseudomonas

Answer 23

gram - bacillo
ubiquitous (in soil and water esp hot tubs)
motile
aerobic
need compromised skin
large innoculation size

Question 24

traits of pseudomonas aeruginosa

Answer 24

colonies produce water-soluble antibacterial pigments
colonies smell like grapes
v. robust
minimal nutritional req. (don’t ferment)
survive in soaps/handcreams and antiseptics

Question 25

pseudomonas virulence factors

Answer 25

capsule 
siderophores (help bind iron)
elastase
exotoxin
phospholipase (hydrolyzes phospholipids in eukaryotic membranes for C source)

Question 26

pseudomonas entry/ability to spread depends on…?!?

Answer 26

avoiding phagocytosis (capsule and exotoxins)
successful adherence to surface (flagella and type 4 pili (creates its own attachment site by cleaving sialic acid to create asialo GM))

Question 27

how does pseudomonas cause damage?

Answer 27

endotoxin - inflammatory resp
exotoxin - kill host cells
elastase - cleaves elastin, collagen, proteinase inhibitors and immune syst components
lasA-serine protease that helps elastase degrade elastin
type III EsoS,T,U, and Y secretion system (transfers virulence factors directly from bacterial to host cytosol)

Question 28

how is cystic fibrosis a risk factor for p. aeruginosa?!?

Answer 28

CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR is dysfunctional in CF patients and causes decreased sialylation of surface glycolipids making them asialo-glycolipids which aeruginosa easily adhere to.
also makes mucus thicker impairing mucociliary system and shielding bact from immune syst

Question 29

diagnosis and treatment for pseudomonas?!?

Answer 29

easily cultured
a lot of hospital strains are resistant
frequently req antibiotic synergism

Question 30

Listeria traits

Answer 30

gram + rod
grows in fridge
motility thru peritrichous flagella and actin polymeriation

Question 31

what is listeriosis

Answer 31

infection of fetus, and immunocompromised
causes bacteremia and meningitis
some people are asymptomatic carriers

Question 32

where do listeria replicate?

Answer 32

w/in cytoplasm

Question 33

listeria virulence factors

Answer 33

internalins - mediate adherence and invasion of cells
listerolsin O - lets them escape from vacuoles
phospholipases - also helps escape from vacuoles and lets it pass thru placenta

Question 34

listeria prevention

Answer 34

avoid unpasturized food
immunocomp people avoid deli meat and soft cheese
antibiotics are effective