Diseases Due to Gram Negative Rods I Flashcards
what shape do enterobacteriaceae have?
rods
bacilli
what are the major pathogens in the enterobacteriaceae?
E. coli
Salmonella
Shigella
Yersinia
how does lipopolysaccharide (LPS) trigger the host immune response?
recognition of the bioactive lipid A domain
what does lipopolysaccharide induce?
potent innate immune response
Escherichia coli is serotyped by ___________________ antigens
O, H, and K
what are the virulence factors of E. coli?
LPS endotoxin
alpha-haemolysin
fimbrial adhesions
adhesions: intimin
exotoxins
what does enterotoxigenic E. coli (ETEC) lead to?
hypersecretory diarrhea
what do enteropathogenic E. coli and Enterohemorrhagic E. coli lead to?
destruction of microvilli
malabsorption, maldigestion
inflammation
who is more susceptible to colisepticemia?
neonates: calves, lambs, poultry
immune-compromised animals
what does oedema disease of pigs result from?
haemolytic E. coli starts in GI tract, then shigatoxin produced causes damage to endothelial cells and perivascular edema
what pathogens cause coliform mastitis?
enterobacteriaceae: E. coli, Klebsiella, Enterobacter
what is coliform mastitis from?
unclean environment
milking cows have relaxed sphincter ani externus
what pathogen causes urogenital tract infections in canines?
uropathogenic E. coli
how can you treat colibacillosis?
isolate
rehydrate and electrolytes
antimicrobials if systemic
NSAID
is Salmonella spp commensal?
no
is Salmonella spp motile?
yes
fimbriae
flagella
can salmonella enter macrophages?
yes and remain latent
how common is salmonellosis as a zoonosis?
extremely common
what is salmonellosis as a zoonosis due to?
contamination of water and soil with feces, meat, eggs, and offal
what causes Pullorum disease?
Salmonella pullorum
who does pullorum disease impact?
young chickens and turkeys
what is found on a postmortem with pullorum disease?
white nodes in lungs
necrotic liver
what are the hosts of Shigella spp?
humans and non-human primates
where do enterobacteriaceae reside?
worldwide
mammalian gut
soil and sewage
can cause variety of infections
useful indicator of food quality and safety
what do enterobacteriaceae do with sugars?
ferment them
how does lipopolysaccharide induce a potent immune response?
complement activation
binding of TLR4 receptor
activated macrophages and neutrophils, leading to inflammation
can lead to massive production of cytokines: septic shock
what motility tools does Escherichia coli have?
peritrichous flagella and fimbriae
enterotoxigenic E coli attaches to surface with ____________________
fimbrial adhesins
what enterotoxins does enterotoxigenic E coli produce?
LT: heat labile
ST: heat stable
exotoxins
cause secretion of Na and Cl
what does the hyperosmotic pressure created by enterotoxigenic E coli cause?
draws water into the lumen
hypersecretory diarrhea
interferes with water reabsorption
what happens with the architecture of the microvilli with enterotoxigenic E coli?
retained
what is enteric colibacillossis caused by?
enterotoxigenic E coli
what predisposes calves, lambs, and piglets to enteric colibacillossis?
stress
environmental contamination
naive immunity
no colostrum
what diarrhea is typical of enterotoxigenic E coli?
very profuse and watery brown diarrhea
how do enteropathogenic and enterohemorrhagic E coli cause disease?
injection of proteins or toxins through type III secretion system
T3SS
what is colisepticemia?
invasion of blood stream by intestinal or extraintestinal coliforms
what is endotexic shock and inflammation in colisepticemia from?
lipopolysaccharide
what are the clinical signs of colisepticemia from endotoxin LPS?
pyrexia, depression, tachycardia
profuse salivation, distended abdomen
with or without diarrhea
meningitis, pneumonia
joint swelling, arthritis, lameness
what is the nutritional and environmental background of oedema disease in pigs?
young pigs, 1-2 weeks post weaning
sudden onset
what are the symptoms of oedema disease of pigs?
paresis, tremor, oedema of eyelids and frontal face, laryngeal oedema (dysphonia)
no diarrhea
flaccid paralysis before death
death 36-48hrs
can coliform mastitis be peracute and fatal?
yes due to enteroxaemia
is coliform mastitis an opportunistic infection?
yes
what can uropathogenic E coli cause in female dogs?
pyometra
cystitis
what can uropathogenic E coli cause in male dogs?
prostatitis
what can uropathogenic E coli cause in cats?
nephritis
how can you control and prevent colibacillosis?
ensure passive immunity transfer through colostrum
immunization of dams against enteropathogenic E coli during pregnancy
improved hygiene
isolation of newly-calved cows
what are the pathogenicity traits of Salmonella?
fimbriae
lipopolysaccharide
T3SS
invasion
systemic infection
latency
what is underlying of a salmonella infection?
stress
poor hygiene
what is the enteric acute form of salmonellosis like?
fever, depression
profuse, foul-smelling diarrhea with blood/mucus/epithelial casts
dehydration, weight loss
abortion
mortality in young
what is the enteric chronic form of salmonellosis like?
can follow acute
intermittent: fever and soft stool
slow emaciation
who get septicemic salmonellosis?
mostly calves, foals, pig growers
what do survivors of septicemic salmonellosis get?
meningitis
arthritis
pneumonia
diarrhea
what causes fowl typhoid?
Salmonella gallinarum
what do Shigella spp cause?
sporadic infections chicken, rabbits, piglets, calves
what do Shigella spp have a tropism for?
intestinal epithelium
what are the mechanisms of Shigella infection?
type III secretion system
intracellular invasion
