Escherichia Flashcards
Gram stain
Negative
Oxygen requirements
Facultatively anaerobic
Shape
Rod shaped
What family is Escherichia in
Enterobactieriacae
Which enterbacteriace are lactose fermenter
-Escherichia
-Klebsiella
Which enterobacteriacae are not lactose fermenters
-Salmonella
-Proteus
-Morganella
-Serratia
-Yersinia
Coliform bacteria
-E. coli
-K pneumoniae
-K. aerogenes
Habitat
-Normal flora of lower intestinal tract
-Soil and water
Antigenic characteristics
-Capsule (K) polysaccharide
-Pilus (F)
-Cell wall (O)
-Flagella (H)
-LPS
Diseases caused by E. coli
-Neonatal diarrhea in cows, sheep, goats, and pigs
-Mastitis in cows
-UTI in dogs and cats
-Metritis and mastitis in mares
-edema disease in pigs
-air sacculitis, cellulitis, and coli septicemia in poultry
Broad classifications
-Intestinal pathogenic (IPEC)
-Extraintestinal pathogenic (ExPEC)
Six categories of IPEC
-Enteropathogenic (EPEC)
-Shiga toxin producing (STEC)
-Enteroinvasive (EIEC)
-Enterotoxigenic (ETEC)
-Enteroaggregative (EAggEC)
-Cytotoxin Necrotizing Factor Producing E. Coli (CNF-PEC)
MacConkey agar
Determine lactose fermentation. Turns pink if positive
Enteropathogenic E. coli
-Attachment pili mediated
-Loss of microvilli
-Invasion and structural changes
-Produce hemolysin
-Cause diarrhea in humans and animals (pigs)
Hemolysins
Obtain iron from lysed RBC
-Alpha (ETEC and ExPEC)
-Enterohemolysin (STEC)
-Cytolysin A many strains
Shiga toxin
two types Stx1 and STx2
-Stx2 involved in edema disease in swine
STEC infections
-Hemorrhagic enteritis and hemolytic and uremic sydrome in humans
-Edema disease in pigs
-Swollen head syndrome in chickens
Most common STEC serotype
O157:H7
Enteroinvasive (EIEC)
-Multiply in the cell
-Invasion and cellular destruction
-Causes bacterimia or septicemia
-Mostly seen in poultry
Enterotoxigenic (ETEC)
-Cholera like
-Attach with pili but do not invade
-Produce enterotoxins
-LT toxin (cholera toxin like)
-ST toxin
LT toxin
A-B toxin
ST toxin
Small proteins
Mode of action of enterotoxins
Reduced absorption of electrolytes and water and hypersecretion of electrolytes and water leading to diarrhea
Enteroaggregative (EAggEC)
-Forms aggregates
-Doesn’t invade
-EAST and hemolysin like toxins
Cytotoxin Necrotizing Factor Producing E. coli (CNF-PEC)
-Attach but do not invade
-CNF toxin causes necrosis
-Causes diarrhea in calves, pigs, and humans
-Mastitis in cows
-UTI in dogs
Extraintestinal pathogenic E coli (ExPEC)
-Septicemia
-Mastitis in dairy cows
-Metritis
-UTI
-Air sacculitis and cellulitis in chickens and turkeys
Inportant virotypes in animals
-ETEC: intestinal infections
-EPEC: intestinal and extraintestinal infections
-STEC: edema disease in pigs
Diseases
Colibacillosis either intestinal or extraintestinal
Modes of infection
-Ingestion
-Inhalation
-Direct infection
Colibacillosis in swine forms
- Neonatal enteritis(ETEC)
- Post weaning diarrhea (EPEC, ETEC, and STEC)
- Edema disease (STEC)
Edema disease
Caused by STEC and Stx2.
-Edema of submucosa of stomach and colon and subcutaneous tissues
-Happens in young recently weaned animals
-Can be due to change in feed or rapid growth or because of diarrhea
Clinical signs of edema disease
-Eyelids, facial area, stomach, colon, mesenteric lymph nodes, colon, gall bladder larynx etc edema
-Peculiar squeal
-Neuro signs: convulsions, ataxia
-Recumbency with paddling of legs
Edema disease mortality
65$ experience death in 1-3 days
Prevention of edema disease
-Separate sick pigs
-Recombinant toxoid vaccine
-Antibiotics in feeds (CTC, enroflaxacin)
Colibacillosis in cattle
-Septicemic form
-Mastitis
Colibacillosis septicemia in cows
In calves deprived of colostrum due to endotoxin shock and death
Coliform mastitis
See in high producing dairy cows, usually mild
-See swelling of udder, discolored mil, blood clots, loss of milk
-Adheres to mammary cell
-Absorption leads to fever deppression and sometimes death
Treatment of mastitis and prevention
-amoxicillin, cephalosporins
-Vaccine based on endotoxin
Colibacillosis in dogs and cats
Usually not diarrhea
-See in genital and urinary tract
-Cystitis and pyometra in females prostatis in males
Virulence factors of UTIS in dogs
-Pili
-Hemolysin
-Cytotoxin necrotizing factor
-Protease enzyme
Avian Colibacillosis
-Diarrea rare
-Can be localized or systemic
-Avian strains don’t cause disease in other animals
-Respiratory infections
-Cellulitis
=Hjarres disease
Air sacculitis
-Inhale fecal dust (ammonia predisposes them)
-Often secondary to viral and mycoplasma
-Causes pneumonia and pleuropneumonia
-Significant economic losses
Cellulitis in poultry
See in broilers
-Infection of subcutis
-Swollen head syndrome caused by STEC
Zoonotic E. coli pathogens
STEC O157:H7 food bourne pathogen
White scour disease
During first week of life in calves. Severe diarrhea with feces full of gas bubbles. Die from dehydration in 3-5 days
Virulence factor of white scours
Entertoxin (STa)
Diagnosis of E. coli
-Age
-Clinical signs
-isolate from fecal sample
Determine surface antigens and serology, can use PCR
-Histopath
Treatment of E. coli
-Aminoglycosides (neomycin)
-Tetracyclines
-IV fluid therapy
Control measures for E. coli
Sanitation and management. Make sure newborns get colostrum
-Vaccinations
O157:H7 in humans
Causes hemorrhagic colitis and in children HUS, can get hemolytic anemia, acute renal failure and thrombocytopenia
Pathology of O157:H7
Colonizes intestinal cells
-Produces Stx to damage endothelial cells
Reservoir for O157:H7
Cattle. Present in GI and shed in feces
Source of infection of O157:H7
-Undercooked beef and unpasteurized milk
-Unpasteurized fruit juices
-Drinking water
-Contaminated leafy veggies
