chapter 11 pt 3 Flashcards
where do listeria monocytogens replicate?
cytoplasm of cells after they induce phagocytosis to get in
-to avoid humoral immune system?
what can listeria monocytogens cause?
neonatal listerosis or meneingitis
how does listeria monocytogens get in?
intestine
-internal mediates attach to an enterocytle and eneter in an endocytotic vacuole
how does listeria monocytogens escape from vacuole?
LLO
-listerolysin luses
-escapes into cytoplasm
how does listeria monocytogens invade other cells?
cytoskeleton gets modified and it moves along fibers by polimerizing actin (comet tail)
-enters that cell in a double vacuole that gets lysed by LLO
-then can cause bloodstream invasion
listerosis cases caused by
dairy, meat, poultry
-can contaminate food or grow in animal intestine
-can be mild or cause septicemia
when is listeriosis worse?
in immunocompromised people
treat listeria monocytogens
-ampicillan
-pasteurization
-cooking
enterobacteriaceae
-facultative anaerobes
-ferment glucose
-reduce nitrate to nitrites
-oxidase negative and catalase positive
-coliforms and non coliforms
coliform
lactose fermenter
how to screen for enterobacteriaceae
selective and differential screening
rapid assay for enterics
BBL enterotube 2
basic mechanisms of diahrrea disease
-toxigenic
-invasive
toxigenic
microbe in intestine, makes a toxin, diahrrea caused by fluid secretion
invasive
bacteria invades cell, gets to blood and is killing
most agents of diahrrea are not?
part of the normal microbiota population
diahrrea makes up?
40% of the worlds infectious disease
18% of deaths
gastroenteritis
diahrrea disease
what triggers immune response and contributed to pathogenicity
surface antigens
outermembrane LPS
-surface antigen
-recognition of repeating oligosaccharides on LPS molecule
-O Ag
K antigen
cell surface polysaccharides
-capsule or slime layer
-v.f.
H antigen
flagella
what have fimbrae?
many enterobacteriaceae
-surface pili
-NOT antigenic proteins
-v.f.
endotoxins and exotoxins are?
virulence factors
most prevalent enteric bacillus
escherichia coli
-in the gut
-aerobic and non fastidious
-150 distinct O antigens and many K and H antigens
-some have plasmid and v.f. others are opportunists
how are e coli differentiated
by surface features
-makes them different stereotypes of e coli
shiga toxin
(stx)
-e.coli toxin/ v.f.
-ab toxin that interferes with protein synthesis by disturbing rRNA binding to ribosome
what gives ecoli specificity for target tissue
fimbrae
-essential for some types of infection
pathogenic strains of ecoli
-enterotoxigenic (ETEC)
-enteroinvasice (EIEC)
-enteropathogenic (EPEC)
-enterohemorrhagic (EHEC)
which is the most serious ecoli
-enterohemorrhagic
-EHEC
-carries shiga toxin gene from the prophage shigella
which ecoli doesnt have LT and ST toxin
-EPEC
-enteropathogenic
-linked to wasting from infantile diarrhea
which ecoli does not invade past the intestine
-EIEC
-enteroinvasice
-causes inflammation of large intestine
-appears like shigella dysentary
-epithelial tissue of the intestine
most common cause of travelers diahhrea
-ETEC
-enterotoxigenic
-diahhrea due to LT and ST enterotoxins
-has fimbrae for adherance
greatest cause of mortality in babies
pathogenic ecoli causing infantile diahrrea
-coliform count
what can coliform count do?
show fecal contamination in water
-ecoli is the proxy bc it is easy to
-find ecoli= finding waste contamination of animal poop
