Card Set Information
Shigella and Yersinia
what are some epidemiological factors associated with shigella?
S.flexenei mostly in underdeveloped countries
S.sonnei mostly in developed countries
Day cares are important setting for outbreak
fecal and oral route
low dose required
no seasonal variance
what are some characteristics associated with shigella?
H2S negative on TSI
Grouped according to O antigen
Have capsule K antigen
what are some clinical characteristic associated with shigella?
might be asymptomatic
early onset ( 1-3)
what are some ways to diagnose shigella?
very fragile in vivo
culture rectal swab or stool
use of selective media (HE, XLD which inhibits gram +)
use of biochemical test
what is the general mechanism of infection and replication in listeria and shigella?
Actin base motility
what does shigella toxin do?
cleaves 28S rRNA in 60S ribosomal unit
disrupts protein synthesis
Lead to cell death
what are factors contributing to pathogonicity of shigella?
incasion ( IpaA, B, C,D)
entrotoxin ( induces cell death of macrophage and cell to cell spread) also escape from phagosome
exotoxin which mediates endothilial damage leading to hemolitic colitis also in some cases hymolytic uremic syndrome
what are some ways to treat shigella?
in vitro suseptibility
start with ampicilin/ trimtroprim and sulfometadoxazole
proper swage disposal
there is no vaccine
what are some general characteristics of uersinia
short or clumpy rods
grouped according to O antigen
capsular K antigen
what are some routes of transmission in yersinia?
host is animal
Y. pestis which is mostly found in rodents, this is a vector borne disease transmitted bu bite of flea
pulmonary pleauge which is highly infectious , transmitted person to person and it is arosel.
what are some ways of disease manifestation?
. bubonic pleauge
onset after 2 to 6 days
enlarged tender lymph node, fever and chill
fever, chill, abdominal pain, bleeding into skin and other organs
* both of above can lead to pneumonic plegue
what are some treatments for the plegues?
chemotherapy ( streptomycin and chloramophonical)
monitoring plegue in rodant population
use of insectisides
what mechanism does yersinia use for invasion?
what is the role of YOP in yersinia?
it help avoid host cell macrophage
YOP H inhibition of phagocytosis
YOP J induction of appotosis
what are some factors contribution to pathogenesis of yersinia?
what is enteric yersinia infeciton mostly associated with?
intake of contaminated food
it is more common in winter
zoonotic > pigs
mostly in young children
4-7 days after exposure
last 1-3 weeks
fever, abdominal pain on right side and bloody diarrhea
usually self limiting
use TMS or aminoglycoside
where and how does Y.enterocolitis grow and what does it cause?
it grows at 4C
also grows on large scale on contaminated blood sample
cause bacteremia after blood transfusion and septic shock