E. Coli Flashcards
(45 cards)
Escherichia characteristics
gram negative coccobacilli, lactose positive, oxidase negative, motile rods. major pathogen. very diverse species.
Shigella are taxonomically also escherichia (only present in humans)
Pathogenicity is strain dependent
Intestinal and extra-intestinal infections
E. coli serotype
O26, K60, F41, H11
E coli virulence factors
cell-associated: endotoxin, capsule, fimbrial adhesins, non-fimbrial adhesins
extracellular: enterotoxins, cytotoxins, siderophores
Enteric pathotypes E coli
ETEC - enterotoxigenic EPEC - enteropathogenic EHEC - enterohemorrhagic VTEC - verotoxigenic RPEC - rabbit pathogenic
extra-intestinal pathotypes E coli
APEC - avian pathogenic NTEC - necrotoxigenic (cattle) Mastitis-causing E coli - cattle MMA - pigs UPEC - dogs (uropathogenic)
ETEC piglets - virulence factors
neonatal: F4, F5, F6 F41, STa, STb. Non-hemolytic
Neonatal - 3 weeks: F4, LT, STa, STb, EAST1. Hemolytic
Post-weaning: F4, F18, LT, STa, STb, EAST1. hemolytic
ETEC piglets pathogenesis
ETEC is found in the intestine of healthy sows. Break in equilibrium between passage to piglets and maternal antibodies = disease. Break in equilibrium may be due to high infection pressure, lowered maternal immunity or appearance of a new type
ETEC piglets diagnosis
CS, age, very smelly feces, dehydration, older piglets have white-grey diarrhea, culture, detection of virulence factors via PCR/agglutination.
ETEC piglets treatment
hydration, antimicrobials
ETEC piglets prevention
keep infection pressure low and maternal immunity high.
Good hygiene, vaccinate sows (2 doses, second 2-6 weeks pre-partum), vaccinate piglets for post-weaning diarrhea, selection for F4 receptor-free piglets
VTEC piglets (edema disease) virulence factors
F18 - adhesion to small bowel
Exotoxin - VT2e or Stx2e (BV necrosis)
Endotoxin - acute mortality
VTEC piglets pathogenesis
sow to piglet transmission
weaning causes stress + change in intestinal flora
excretion –> increased infection pressure –> contamination of other piglets
Toxin productions causes enterorrhagia (hyperacute), high BV permeability (acute), intravascular coagulation (slow)
endotoxin causes shock and acute mortality
VTEC in piglets diagnosis
CS (3 weeks post weaning - acute mortality, diarrhea, anorexia, edema), bacteriology and confirmation of virulence factors
VTEC in piglets treatment
affected animals: fasting to eliminate toxin, antimicrobial therapy
not-yet-affected: antimicrobial therapy
VTEC in piglets prevention
reduce stress at weaning, starter feed before weaning, good fibre content in feed, adaptation of intestinal flora (probiotics, organic acids, zinc oxide), vaccination 2-4 days old, select for pigs that are F18-receptor negative
EPEC in pigs virulence factors
BFP - bundle forming pili, initial attachment
attaching and effacing: intimate attachment (eae)
T3SS - translocates bacterial effector proteins into target cell
EPEC in pigs diagnosis
bacterial isolation and detection of eae gene
EPEC in pigs treatment
oral antimicrobials
EPEC in pigs prevention
no vaccine, little is known to prevent
E. Coli UTIs in pigs predisposing factors
hygiene, water intake, obstipation, age, individual differences
E. Coli UTIs in pigs diagnosis
CS (anorexia, hematuria, vaginal exudate), bacteriology
E. Coli UTIs in pigs treatment
culling, antibiotics for 3 weeks
MMA or PPDS in pigs etiology
metritis-mastitis-agalactiae, post partum dysgalactiae syndrome
hereditary, hormonal, feed, infectious (e. coli)
Bovine ETEC virulence factors
in animals less than 3 days old. Adhesion via fimbriae - F5, F41, F17, CS31A, also has STa and STb toxins
