Lecture 22 - Bacteriology GI/Liver 1 Flashcards
what are the 2 benefits of bacteria in the GI tract
- digestion including fermentation
- competitive inhibition
what 4 factors cause the shedding of bacteria in the GI tract
- stress
- high-density housing
- diet changes
- antibiotic use
what factors could cause the pathogenesis of bacteria
- organ
- host
how can a host resist colonization?
- acidic pH
- epithelial cells
what do the presence of epithelial cells contribute to resistance of colonization
- physiochemical barrier
- IgA
- recruitment of leukocytes
T/F: mucus is the main way a host will resist colonization in the GI
TRUE
what are probiotics? how do they help host protective strategies?
probiotic: antibacterial substance
- competitive inhibition of toxin/pathogen adherence
- reestablish host immunity
- regulate host immune response and epithelial cell function
T/F: probiotic bacteria needs prebiotics to survive
TRUE
what are prebiotics? be specific
fructooligosaccharides
what can impede host protection?
- chemical insults
- change in pH (proton-pump inhibitor)
- trauma (FB or obstruction)
- immune impairment
- inflammation
match the protective mechanism to its threat
- mucus
- gastric acid
- mucosal IgA
- Bifidobacterium spp.
a. poor diet
b. immune impairment
c. trauma
d. proton-pump inhibitor
1 = c
2 = d
3 = b
4 = a
what are the 4 mechanisms of bacterial pathogenesis
- adhesion
- colonization
- invasion
- toxins (endo or exo)
what is the type III secretion system
protein “appendage” common to gram-negative bacteria used for sensing cells and injecting effector proteins
what are the 4 bacterial mechanisms of defense
- enterotoxin production
- enteroadherence
- mucosal invasion
- submucosal invasion
what does “heat liable” mean
disabled at high temperatures
describe enterotoxin production
- bacteria attach to epithelium and secrete heat-liable toxin
- increased cAMP
- increased Cl- secretion and decreased sodium absorption
- loss of water and electrolytes
what is enteroadherence
use of adhesions to attach to the surface
describe mucosal invasion in 3 steps
- bacteria penetrate submucosa
- marked neutrophilic inflammation
- carrier state develops
T/F: submucosal invasion leads to localized spread of bacteria
FALSE - systemic
what bacteria uses all of the protective mechanisms
e. coli
how do bacteria spread to the liver?
through the bloodstream via the
1. portal v.
2. hepatic a.
3. umbilical v.
what route do bacteria take through the intestines to the liver
biliary tree
if an animal has multiple random liver lesions and lesions present in other organs, how was it infected?
systemic infectious process
if an animal has multiple random liver lesions and no evidence of lesions elsewhere, how was it infected?
GIT via portal circulation
if there is a single liver lesion in a young animal with a swollen navel, how was it infected?
via umbilical vein
if the liver lesions are confined to the liver surface, how was it infected?
peritoneal infectious process
define bacterial sepsis
bacteria spread through blood or lymph
what are individual risk factors for GI/Liver disease?
- age (younger/geriatric more susceptible)
- immunocompromised
- pregnant
what are the environmental risk factors for GI/Liver disease?
- poor hygiene
- high density
- transport/movement
- poor diet
