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65 Cards in this Set

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Escherichia family:
Escherichia family:
Enterobacteriaceae
Enterobacteriaceae general features (7)
Enterobacteriaceae general features (7)
1) G-
2) facultatively anaerobic
3) rod shaped
4) Ferment glucose to acid and gas
5) May or may not ferment lactose
6) oxidase negative
Enterobactericeae Habitat:
Enterobactericeae Habitat:
GI tract
Soil
water
Enterobactericeae Mode of Infection
Enterobactericeae Mode of Infection:
always ingestion
Enterobactericeae
Lactose fermenter (2 genera)
Nonlactose fermenters (1 genera)
Enterobactericeae
Lactose fermenter (2 genera)
1) Escherichia
2) Klebsiella
Nonlactose fermenters (1 genera)
1) Salmonella
Enterobactericeae Members
Major Pathogens (3 genera)
Minor Pathogens (3 genera)
Less important (3 species)
Enterobactericeae Members
Major Pathogens (3 genera)
1) Escherichia
E. Coli
2) Salmonella
S. enterica
3) Yersinia
Y. pestis
Y. pseudotuberculosis
Y. enterocolitica
Minor Pathogens (3 genera)
(Opportunistic)
1) Klebsiella
K. pneumoniae
2) Enterobacter
E. aerogenes
3) Proteus
P. mirabilis
P. vulgaris
Less important (3 species)
1) Serratia marcescens
2) Morganella morganii
3) Edwardsiella tarda
Coliform bacteria:
Coliform bacteria:
refers to lactose fermenting Escherichia, Klebsiella and Enterobacter
causes coliform mastitis in cows
MacConkey test:
MacConkey tests:
Selective G-, G+ inhibited
combination of bile salts and crystal violet)
Differential: lactose vs. nonlactose fermenter--> acid
change pH
pink --> positive acid pH --> lactose fermenter
white --> negative, colorless, neutral pH
Escherichia coli general features: (5)
Escherichia coli general features: (4)
1) G-
2) rod
3) facultative anaerobic
4) lactose-fermenter: MacConkey - Pink
5) Blood agar: non-hemolytic
E. Coli Habitat
E. Coli Habitat:
Normally in soil, water, lower SI and LI
Majority of E. colie in normal flora is nonpathogenic
Shiga-toxin producing E. coli (STEC) in normal flora of cattle and other ruminants are pathogenic to humans.
Present in all animals some types normal in some animals but pathogenic in humans
Antigenic characteristics, serotypes based on (4)
Antigenic characteristics serotypes based on(4):
1) O - antigen: heat stabl, 170+ types
2) H - antigen: Flagella, heat labile, protein; 56+ types
3) K - antigen: Capsule, carbohydrate, protein or both, 80+ types
4) F - antigen: Pilus (Fimbrial), heat labile protein, plasmid encoded, mediate adhesion of bacterial cells
Antigenic characteristics
O - antigen (3)
Antigenic characteristics
O - antigen (3):
1) heat stable
2) LPS
3) 170+ types
Antigenic characteristics
H - antigen: (4)
Antigenic characteristics
H - antigen: (4)
1) Flagella
2) heat labile
3) protein
4) 56+ types
Antigenic characteristics
K - antigen: (3)
Antigenic characteristics
H - antigen: (3)
1) capsule
2) carbohydrate, protein or combination - typically polysaccharide
3) 80+ types
Antigenic characteristics
F - antigens (4)
Antigenic characteristics
F - antigens (4)
1) Pilus (Fimbrial) antigens mediate adhesion of bacterial cells
2) protein
3) heat labile
4) plasmid encoded
Summary of E. coli antigens (4)
Location:
Chemistry:
Pathogenic function:
Summary of E. coli antigens (4)
O
Location: somatic
Chemistry: lipopolysaccharide
Pathogenic function: endotoxin production

K
Location: Capsule
Chemistry: Polysaccharide
Pathogenic function: Adhesion, protection

H
Location: Flagella
Chemistry: Protein
Pathogenic function: Motility

F
Location: Pilus
Chemistry: Protein
Pathogenic function: Adhesion
Classification of an organism within a species based on ______ ______
Classification of an organism within a species based on antigenic structure
Certain serotypes associated with specific species (3 examples)
Certain serotypes associated with specific species (3 examples)
F4 (K-88): Swine
987P: Swine
F5 (K-99): calves and swine
Pathogenic Mechanisms
What determines virulence?
Pathogenic Mechanisms
What determines virulence?
Most serotypes not pathogenic
Some serotypes have acquired genes (plasmids) that impart virulence by encoding factors such as
1) ability to attach to host cells
2) toxin produciton
3) ability to invade host cells
How many categories of virotypes and based on? (4)
Five major categories (virotypes) based on:
1) patterns of attachment on host cells
2) effects of attachment on host cells
3) production of toxins
4) invasiveness
Virotyping
Virotyping: Classification scheme based on virulence factors
5 virotypes
5 Virotypes
1) Enteropathogenic (EPEC)
2) Attaching and Effacing (AAEC), Enterohemorrhagic (EHEC), Shiga toxigenic (STEC)
3) Enteroinvasive (EIEC)
4) Enterotoxigenic (ETEC)
5) Enteroaggregative (EAggEC)
Virotype: Enteropathogenic (EPEC)
1) Attachment _____ mediated
2) Cause loss of:
3) ____ cells and cause _____ _____ in cells
4) Produce _____
6) Causes _____ in _____, particularly _____, rarely in ______
Virotype: Enteropathogenic (EPEC)
1) Attachment pili mediated
2) Cause loss of: microvilli (effacement)
3) Invade cells and cause structural changes in cells
4) Produce cytotoxin
6) Causes diarrhea in humans, particularly children, rarely in animals
Virotype: Attaching and Effacing (AEEC), Enterohemorrhagic (EHEC), Shiga Toxigenic (STEC)
1) Attach and cause:
2) Attachment mediated by:
3) Invade and cause _____ _____
4) Produce ____-_____ ____
Virotype: Attaching and Effacing (AEEC), Enterohemorrhagic (EHEC), Shiga Toxigenic (STEC)
1) Attach and cause: loss of microvilli (effacement)
2) Attachment mediated by: an adhesin termed intimin
3) Invade and cause structural changes
4) Produce shiga-like toxin
Shiga-like toxin (Stx)
1) _____ and ____ resembe cytotoxin of _____ _____
2) Toxins: heat ____
3) Lethal for ____ ____ ___ ()
4) Protein: _ subunits, function
Shiga-like toxin (Stx)
1) biologically and structurally resemble cytotoxin of Shigella dysenteriae
2) Toxins: heat labile
3) Lethal for cultured vero cells (verotoxin) (vero = cells used in tissue culture in lab)
4) Protein: 2 subunits, A & B function: B binding
Stx Toxin types # = ?
Stx Toxin types = 2
Shiga toxin identical to S. dysentieriae =
56% homology =
Variants of Stx2 =
_____ causes edema disease in swine
Shiga toxin identical to S. dysentieriae = Stx1
56% homology = Stx2
Variants of Stx2 = c,d,e,f
Stxe causes edema disease in swine
Gene encoding SLT found on _____ _____
Mechanism:
Lethal to _____, enterotoxic to ______
Cytotoxic to _____ _____ cells, explains _____
Gene encoding SLT found on temperate bacteriophage
Mechanism:
Lethal to mice, enterotoxic to rabbits
Cytotoxic to vascular endothelial cells, explains edema
EHEC is associated with diseases
1) in humans
2) in children
3) in pigs
EHEC is associated with diseases
1) in humans: Hemorrhagic enteritis (colitis)(also in calves but only if immune deprived)
2) in children Hemolytic/Uremic Syndrome (HUS) --> kidney failure
3) in pigs Edemadisease
Enteroinvasive (EIEC)
1) ______ inside the cell --> referred to as _____-_____
2) Invade _____ and destroy ____ --> (___)
3) Cause _____ or _____
4) Mostly seen in ____
5) No ____ destruction
Enteroinvasive (EIEC)
1) Multiply inside the cell --> referred to as Salmonella-like
2) Invade tissues and destroy cells --> (can get into blood)
3) Cause bacteremia or septicemia
4) Mostly seen in poultry
5) No villi destruction
Enterotoxigenic (ETEC)
1) ____ but do not ____ --> also referred to as _____-____
2) Most important for _____
3) Adhere to ____ ____ ____ but __ ___ _____
4) Produces 2 toxins: type, info
Enterotoxigenic (ETEC)
1)Attach but do not invade --> also referred to as Cholera-like
2) Most important for animals
3) Adhere to small intestinal mucosa but do not invade
4) Produces 2 toxins: type, info:
enterotoxins
1) LT: heat labile - Cholera toxin- like
2) ST: heat stable
ETEC LT Toxin
1) Has ____ dissimilar polypeptide chains
2) Function of chains:
3) Two types of LT:
ETEC LT Toxin
1) Has 2 dissimilar polypeptide chains A and B
2) Function of chains: heat stable A: fluid accumulation, B contains subunits for binding
3) Two types of LT: LT-I, and LT-II
ETEC ST Toxin
___ Subgroups
Methanol soluble:
Methanol insoluble
____ has the ability to induce accumulation of fluid in the intestine of suckling mice tht have received the toxin orally or intragastically
____ is inactive in the infant mouse assay
Point of assay:
ETEC ST Toxin
2 Subgroups
Methanol soluble: STa
Methanol insoluble: Stb
STa has the ability to induce accumulation of fluid in the intestine of suckling mice tht have received the toxin orally or intragastically
STb is inactive in the infant mouse assay
Point of assay: to detect if if toxin contains STa or not
Mode of action of enterotoxins (3 steps each)
LT:
STa:
Mode of action of enterotoxins (4 steps each)
LT: cells increase adynlate cyclase --> increase cAMP --> absorption and hypersecretion of electrolytes and H20 = diarrhea
STa: cells increase guanylate cyclase --> increase cGMP --> absorption and hypersecretion of electrolytes and H20 = diarrhea
Enteroaggregative (EAggEC)
New group
____ in small aggregates
____ to small _____ cells but do not _____
Produce __-____ toxin called ____ for (_) and
Causes ____ in ____
Enteroaggregative (EAggEC)
New group
Clump in small aggregates
Bind to small intestinal cells but do not invade
Produce ST-like toxin called EAST for (enteroaggregative heat stable enterotoxin) and a hemolysin-like toxin
Causes persistant diarrhea in children
Cytotoxin Necrotizing Factor producing E. coli (CNF-PEC)
not well categorized
heat labile
produces necrosis
E. Coli Diseases
General Term:
3 forms:
E. Coli Diseases
General Term: Colibacillosis
3 Forms:
1) Diarrheal (most common)
2) Septicemic (Colisepticemica)
3) Suppurative: e.g. mastitis
2 Most important E. coli types causing infections in farm animals:
2 Most important E. coli types causing infections in farm animals:
1) ETEC: causes enteritis
2) AEEC: causes edema in pigs, Shiga-systemic effect
E. Coli Mode of infection
(2)
E. Coli Mode of infection
(2)
1) Indirect: Oral, at birth in vagina or when they suckle
2) Direct: entrance of the organism into a location in the body in which it is not part of the normal flora
E. Coli
Colibacillosis in Swine
3 types
E. Coli
Colibacillosis in Swine
3 types
1) Neonatal enteritis (ETEC)
2) Weanling enteritis (Post weanling diarrhea) (ETEC)
3) Edema disease (AAEC)
E. Coli
Colibacillosis in Swine
Neonatal enteritis
1) Occurs:
2) Pathogenesis: entry, _____ (mediated by ____)Produce ______
3) After 12 hr exhibit profuse _____ (______) mortality:
E. Coli
Colibacillosis in Swine
Neonatal enteritis
1) Occurs: in first 4 days of life
2) Pathogenesis: entry, ETEC colonize mucosa of small intestine (mediated by pili)Produce 1+ enterotoxins LT and STa
3) After 12 hr exhibit profuse diarrhea (pale yellow and watery) mortality: 90% due to dehydration
E. Coli
Colibacillosis in Swine
Weanling enteritis (Post weaning diarrhea)
1) Caused by:
2) Complication of weaing in pigs with ____ _____ diet
3) Pigs develop ____, ____, ____ and ____
4) Mortality:
E. Coli
Colibacillosis in Swine
Weanling enteritis (Post weaning diarrhea)
1) Caused by: hemolytic strains
2) Complication of weaing in pigs with high grain diet
3) Pigs develop diarrhea, depression, anorexia and fever
4) Mortality: lower than neonatal form
E. Coli
Colibacillosis in Swine
Edema Disease
1) Caused by:
2) Seen in pigs:
3) Prominent feature:
Edema Disease
1) Caused by: absorption of toxin (Shiga-like or verotoxin)
2) Seen in pigs: 7-10 days afer weaning
3) Prominent feature: edema of submucosa of stomach and mesocolon
E. Coli
Colibacillosis in Swine
Edema Disease
Predisposing factors (4)
E. Coli
Colibacillosis in Swine
Edema Disease
Predisposing factors (4)
1) Age - weanlings most common
2) Change of feed - most common during weaning
3) Rapid growth
4) Diarrhea - seen 1-2 days before onset
E. Coli
Colibacillosis in Swine
Edema Disease
Pathogenesis
1) Colonization of:
2) Toxin:
3) Effect:
4)Mortality:
5)Prevention:
E. Coli
Colibacillosis in Swine
Edema Disease
Pathogenesis
1) Colonization of: intestine
2) Toxin: Stx2e produced, absorbed and carried in blood to various targets, toxin acts on endothelial cells of small arteriees which become permeable to fluid --> edema
3) Effect: edema of eyelids, facial area, cardiac zone of stomach, mesenteric lymph nodes, gall bladder, larynx
4)Mortality: high: 65% (1-3 days after signs)
5)Prevention: no vaccine, separate from sick pigs, abx in feed
E. Coli
Colibacillosis in Cattle
Diarrhea form:
1)called:
2)develop:
3)become severely:
4)Death occurs:
5)Virulence factor:
E. Coli
Colibacillosis in Cattle
Diarrhea form:
1)called: white scour - partially digested milk is excreted
2)develop: severe diarrhea with malodorous feces full of gass bubbles
3)become severely: dehydrated
4)Death occurs: 3-5 days
5)Virulence factor: STa (enterotoxin
E. Coli
Colibacillosis in Cattle
Septicemic form:
1) sequel to:
2) also in:
3) virulenc factor is:
4) fatal course:
E. Coli
Colibacillosis in Cattle
Septicemic form:
1) sequel to: colostrum deprivation
2) also in: colostrums-fed animals that failed to absorb immunoglobulins
3) virulenc factor is: endotoxin
4) fatal course: endotoxic shock
E. Coli
Colibacillosis in Cattle
Coliform Mastitis
1) frequency
2) Pathogenesis
-entry:
-adherence to:
-release:
-absorbption of ____ leads to:
E. Coli
Colibacillosis in Cattle
Coliform Mastitis
1) frequency: very common
2) Pathogenesis
-entry: of E. Coli through meatus (teat canal)
-adherence to: mammary cells
-release: of endotoxin
-absorbption of endotoxin leads to: fever, depression, etc
E. Coli
Colibacillosis in lambs
Similar to:
Enteric forms occur:
Bacteremic forms result in:
E. Coli
Colibacillosis in lambs
Similar to: pigs and calves
Enteric forms occur: 2-8 days old
Bacteremic forms result in: sudden death
E. Coli
Colibacillosis in Horses
Mares:
Systemic:
Localized:
Foals w/o _____ succumb to infection
Signs:
E. Coli
Colibacillosis in Horses
Mares:
Systemic: abortion
Localized: acute mastitis
Foals w/o colostrum succumb to infection
Signs: fever, rapid pulse, dullness, and weakness (no enteritis)
E. Coli
Colibacillosis in Dogs and Cats
Isolated from:
Pathogen mostly frequently implicated in:
Infection manifested as:
Invasion of endometrium causes:
E. Coli
Colibacillosis in Dogs and Cats
Isolated from: genital and urinary tract infections
Pathogen mostly frequently implicated in: urinary tract infections
Infection manifested as: cystitis (prostatis)
Invasion of endometrium causes: pyometra
E. Coli
Colibacillosis in Poultry
Rarely implicated in:
Typically:
Coli-Granuloma (Hjarre's Disease):
Respiratory ifnection:
E. Coli
Colibacillosis in Poultry
Rarely implicated in: diarrheal disease
Typically: localized or systemic (colisepticemia)
Coli-Granuloma (Hjarre's Disease): granulomatous lesions in the walls of intestinal tract, liver and lungs
Respiratory infection: air sacculitis resulting from inhalation of fecal dust - pneumonia
E. Coli
Diagnosis
Based on: (5)
E. Coli
Diagnosis
Based on: (5)
1) clinical history
2) age of animal (neonate)
3) clinical signs
4) confirmation by fecal culture usu. suspect Salmonella
5) interpretation of an isolate from GI tract
E. Coli
Methods to distinguish pathogenic from nonpathogenic strains (3)
E. Coli
Methods to distinguish pathogenic from nonpathogenic strains (3)
1) determination suface antigens & detection of toxin producing strains
2) Demonstration of adherence of e. Coli to intestinal epithelium (electron microscopy)
3) Detection of DNA sequences that code for enterotoxins (gene probe or PCR)
E. Coli
Methods to distinguish pathogenic from nonpathogenic strains
determine surface antigens (3)(3 techniques)
detection of toxin producing strains (4 techniques)
E. Coli
Methods to distinguish pathogenic from nonpathogenic strains
determine surface antigens (3)
1)O, 2)K, 3)pilus
(3 techniques)
1) Slide agglutination
2) ELISA
3) Flourescent antibody technique
detection of toxin producing strains (4 techniques)
1) Ligated intestinal loop technique: ligated ileal loops of rabits injected - pos indicated by fluid accumulation
2) Adrenal cells assay: detect ion of heat-labile enterotoxin (morphological changes)
3)Infant mouse - supernatant orally or injected into stomach - intestines examined for fluid accumulation
4) Elisa technique for HLT
E Coli
Control Measures (3)
E. Coli
Control Measures (3)
1) Good sanitationand management
2) Newborn animals are passively protected from colostrum
3) Vaccination -
a.Autogenous bacterins made from killed cells and adjuvant
b. Pilus vaccines
c. J-5 (based on endotoxin) (mutant strain of E. coli) vaccine for mastitis (LPS vaccine)
E coli O157:H7
belongs to:
first recognized:
# infections/year:
# deaths/year:
Causes:
E coli O157:H7
belongs to: STEC
first recognized: 1982 Michigan/Oregan
# infections/year: 40,000
# deaths/year: 250
Causes: hemorrhagic colitis, hemolytic uremic syndrome (most common cause of kidney failure in children) characterized by acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia
E. Coli 0157:H7
SMaC appearance:
response to acid pH:
Produces what toxin:
What are the results of the toxins:
E. Coli 0157:H7
SMaC appearance: non sorbitol fermenter - colorless colonies distinguishable from other E. coli
response to acid pH: resistant survives 3.4 several days
Produces what toxin: Shiga-like toxin (verotoxin)
What are the results of the toxins: damages endothelial cells, leads to thrombocyte aggregation and capillary vessels damage in kidney or other organs
E. Coli O157:H7
Present where?
Prevalence higher in?
Prevelence higher when?
In feedlots what percent shedding E. Coli and what percent had at least one animal positive?
E. Coli O157:H7
Present where? GI tract of healthy cattle <10^2-10^5/g of feces
Prevalence higher in? young calves than adult
Prevelence higher when? summer and early fall
In feedlots what percent shedding E. Coli and what percent had at least one animal positive? 28% and 72% respectively
E. Coli O157:H7
Frequent source of infection:
E. Coli O157:H7
Frequent source of infection:
undercooked ground beef and unpasteruized milk, unpasturized fruit juice, contaminated vegetables (alfalfa sprouts)
also drinking water and recreational water,
E. Coli O157:H7
Hemorrhagic Colitis and Hemolytic Uremic Syndrome (HUS)
O157:H7 causes:
Pathogenesis: (5)
Incubation:
Symptoms:
E. Coli O157:H7
Hemorrhagic Colitis and Hemolytic Uremic Syndrome (HUS)
O157:H7 causes: a disease that varies frommild diarrhea lasting 2-9 days to severe hemorrhagic colitis
Pathogenesis: (5)
1) colonization of intestine
2) production of SLT in intestine
3) absorption of SLT
4) binding SLT to vascular endothelium in target organs
5)damage to endothelial cells
Incubation: 3-9 days
Symptoms: severe abdominal pain, 24hrs later grossly bloody diarrhea
E. Coli O157:H7
Prevention (4)
E. Coli O157:H7
Prevention (4)
1) Adequate heating - ground peaf to an internal temp of 160 F for 15sec
2) Routine pasteurization of milk
3) Implementation of Hazard Analysis & Critical Control Points
4) HAACP in Slaughtering and Meat processing proceedures
Summary
Escherichia
species:
G?, shape? oxygen:
Lactose fermenter?
Antigens:
Summary
Escherichia
species: 1: E. Coli
G-, shape rod, facultative anaerobe
Lactose fermenter!
Antigens: O, K, F, and H
O (endotoxin): virulence factor if in blood
F: pili: attachment, initiates disease and colonizaiton, antigen that induces antibodies which can protect the animal against infection
Escherichia
Pathogenic Types (Virotypes):#
2 most important:
what do theay attack?
Mode of infection:
Escherichia
Pathogenic Types (Virotypes):5
2 most important: ETEC (enterotoxins) and STEC (Shiga toxin)
ETEC : enterocytes
STEC: Vascular endothelial cells
Mode of infection: oral
Escherichia
Diseases:
Diarrhea in neonates (species and due to what toxin?)
Edema disease in what species and due to what toxin?
Mastitis in what, due to what toxin?
What in mares?
What in dogs and cats
E. coli 0157:H7 is a ____-_____ pathogen
Escherichia
Diseases: Colibacillosis
Diarrhea in neonates (species and due to what toxin?) calves, piglets and lambs, (enterotoxins)
Edema disease in what species and due to what toxin? (pigs - shiga toxin)
Mastitis in what, due to what toxin? cows due to endotoxin
What in mares? metritis, abortion and mastitis
What in dogs and cats: UTI
E. coli 0157:H7 is a food-borne pathogen