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42 Cards in this Set

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Salmonella
general features
G:
shape:
oxygen:
lactose?
motile by:
important:
Habitat:
Salmonella
general features
G: -
shape: rod
oxygen: facultatively anaerobic
lactose? nonlactose fermenters
motile by: peritrichous flagella
important: zoonotic pathogen
Habitat: intestinal tract of vertebrates including fish, reptiles and mammals
Salmonella Characterics
3 types, and characteristics
Salmonella Characterics
3 types, and characteristics
1)0(Somatic) antigen - LPS 9endotoxin), ehat stable, designated by Arabic numerals, may have more than 1, classified in to 50 groups A-Z and 51-65, majority B,C,D,E
2) H (Flagellar) antigens: heat labile, lower case alphabet P phase 1, Arabic numbers H phase 2
3) Vi (Virulence or Capsular) antigens: heat stable, composed of polysaccharide, not for erotyping only 3 types have: S Typhi, S Hersfeldii, and S. Dublin
example Salmonella typhimurium it1, 4, [5], 12: i: 1,2
explain
example Salmonella typhimurium it1, 4, [5], 12: i: 1,2
it1, 4, [5], 12 are O antigens, it means present due to phage conversion, [] means present or absent, i isflagellar antigen, 1,2, capsular antigens
Salmonella Classification
2 species, and subspecies
Salmonella Classification
2 species, and subspecies
1) S. Enterica
subspecies: enterica, salmae, arizonae, diarizonae, indica, & houtenae
2) S. bongori - non pathogenic
Salmonella should be called by:
Salmonella should be called by:
species, subspecies and serovar
commpon practice, serovar as species: S. Typhimurium
Salmonella species
Salmonella species
over 2,300- species or sero-varities (serotypes)
Species nomenclature:
named for: (2 with examples)
Species nomenclature:
named for: (2 with examples)
disease syndrom cause:
S. Pullorum
S. Abortusequi
S. Abortusovis
S. Abortusbovis
location first isolated
S. Manhattan
S. Sandiego
S. Texas
S. Arizona
Host adaptation
Grouped according to association with hosts
Host adaptation
Grouped according to association with hosts
Group 1 human host, S. Typhi, S.Parathypi, S. Schottmulleri, S. Hirchfeldii, S. Sendai
Group II Cattle - S. Dublin
Swine, Sheep, Horse, Poultry (poultry strains only affect poultry)
Group III Unadapted - Most species S. Typhimurium
Salmonella
Mode of infection (4)
Salmonella
Mode of infection (4)
1) oral transmission via feces, animalfeeds and animal protein supplements
2) transovarian transmission
3) contaminated milk and milk products
4) Flies - carry on body surface or in digestive tract
Salmonella Predisposing Factors
Salmonella Predisposing Factors
Stress, e.g. shipping, cold, crowding
Horse - stress of hospitalization or surgery
Many animals asymptomatic carriers, with stress infection develops
2 sources: clinically affected animals and asymptomatic carriers
Salmonella Virulence Factors (5)
Salmonella Virulence Factors (5)
1) Enterotoxins
2) Cytoxins
3) LPS
4) Sideorpores
5) Heat-Shock Proteins
Salmonella
Virulence Factors
Enterotoxins (3 Properties)
Salmonella
Virulence Factors
Enterotoxins
1) Cholera toxin-like
2) Structurally and functionally similar to enterotoxin of E. coli
3) Heat labile
Salmonella
Virulence Factors
Cytotoxins #?
damage:
Salmonella
Virulence Factors
Cytotoxins # 3
damage: to intestinal epithelial cell
Salmonella
Virulence factors
LPS
cause: (2)
proof
Salmonella
Virulence factors
LPS
cause: (2)
1) vascular damage and thrombosis in intestine
2) systemic changes (fever, disseminated intravascular coagulation, circulatory collapse, shock
proof: mutants with defect inLPS are less virulent
Salmonella
Virulence factors
Flagella
role:
Salmonella
Virulence factors
Flagella
role: motility increases chance of organism coming into contact with epithelial cells
Salmonella
Virulence factors
Siderophores
What are they?
Who makes them?
What do they do?
E.g.
Salmonella
Virulence factors
Siderophores
What are they? iron chelatorsthat have a high affinitiy for iron
Who makes them? bacteria
What do they do? capture iron in host fluids and return to bacteria through specific outer membrane
E.g. S. Typhimurium makes enterochelin - phenolate siderophore
Salmonella
Virulence factors
Heat-Shock Proteins
produced:
Essential for:
Salmonella
Virulence factors
Heat-Shock Proteins
produced: in response to stress of bact
Essential for: for survival in macrophages
Salmonella
Pathogenesis
Intestinal infections (3)
Salmonella
Pathogenesis
Intestinal infections (3)
1) Colonization of intestine
a)organizms reach intestine
b)adhere to enterocytes
c) adhere to receptors on epithelial cells
d) invade and dmage intestinal epithelium
e) stimulate fluid production and excretion
f) stress allows attachment
KEY FEATURE: Ability to survive & multiply inside macrophages
2)Invasion of intestinal epithelium
a) involves ileum villous tips
b) ability of Salmonella organisms to srvie and multiply inside cells is critical to the outcome of the infection:
Iable to resist destructive processes
II bacterium protected from antibiotics, antibodies and complement
c) enteritis results in a shortening and distortionof villik degeneration and abnormal extrusion of enterocytes, increased emptying of goblet cells (increased mucus production ) and neutrophilic infiltration and migration into the lumen (neutrophil shedding in feces)
3) Stimulation of fluid production and excretion
a) net secretion of water, bicarbonate,and chloride into the lumen
b) loss of epithelial cells results in impaired absorption
Salmonella
Pathogenesis
Intestinal Infections
Colonization of intestine
Salmonella
Pathogenesis
Intestinal infections
1) Colonization of intestine
a)organizms reach intestine
b)adhere to enterocytes
c) adhere to receptors on epithelial cells
d) invade and dmage intestinal epithelium
e) stimulate fluid production and excretion
f) stress allows attachment
KEY FEATURE: Ability to survive & multiply inside macrophages
Salmonella
Pathogenesis
Intestinal Infections
Invasion of intestinal epithelium
Salmonella
Pathogenesis
Intestinal Infections
Invasion of intestinal epithelium
2)Invasion of intestinal epithelium
a) involves ileum villous tips
b) ability of Salmonella organisms to srvie and multiply inside cells is critical to the outcome of the infection:
Iable to resist destructive processes
II bacterium protected from antibiotics, antibodies and complement
c) enteritis results in a shortening and distortionof villik degeneration and abnormal extrusion of enterocytes, increased emptying of goblet cells (increased mucus production ) and neutrophilic infiltration and migration into the lumen (neutrophil shedding in feces)
Salmonella
Pathogenesis
Intestinal Infections
Stimulation of fluid production and excretion
Salmonella
Pathogenesis
Intestinal Infections
Stimulation of fluid production and excretion
3) Stimulation of fluid production and excretion
a) net secretion of water, bicarbonate,and chloride into the lumen
b) loss of epithelial cells results in impaired absorption
Salmonella
systemic infections pathway (3)
Salmonella
systemic infections (3)
1) Free Salmonella in mucosa or submucosa are transported via lymphatics to regional lymph nodes
2) From lymph noedes S travel via efferent lymph vessels, drain into blood circulation
3) Bacteria are filtered out of circulation by RE system particularly in spleen and liver
Salmonella
Key virulence factor:
Salmonella
Key virulence factor:
LPS (endotoxin)
Salmonella
what causes septicemic disesease?
septicemic disease & host
Salmonella
septicemic disease & host
host adapted produce septicemic disease
S. Typhi in humans --> typhoid, S. choleraesuis in pigs. S. Dublin in cattle --> abortion, S. Abortusovis in sheep, S. Abortusequi in horse --> abortion
Salmonella diseases(4)
Salmonella diseases(4)
1) enteritis (diarrhea)
2) Septicemia - systemic salmonellosis
3) abortion
4) food piosoning in humans (actually an infection) 24 hr diarrhea
Salmonella
Bovine Salmonellosis
2 important seroypes:
symptoms
Salmonella
Bovine Salmonellosis
2 important seroypes:
S. Dublin - host adapted
S. Typhimurium
symptoms
Adult cattle: fever, depression, severe diarrhea with blood and mucus in feces, abortion common sequel
Salmonella
Calf Abortion mechanisms
Salmonella
Abortion mechanisms
culture positive cases: bacterimia in dam results in infection of placenta and/or fetus -- resulting fetal death
culture negative case: bactereimia release of prostaglandin (PGF2alpha) subsequent lysis of corpus luteum, aborition follows in 2-3 days, placenta culture negative
Equine Salmonellosis
Serotypes
Symptoms
Equine Salmonellosis
Serotypes
S. Typhimurium - most common
S. Newport
S. Enteritidis
S. Heidelberg
S. abortusequi - disappeared in US
Symptoms
acute form: fever, anorexia, depression and diarrhea
Foals-septicemia; highly fatal infection
animals that survive acute form have diarrhea for months
Swine Salmonellosis
Serotypes
Symptoms
Swine Salmonellosis
Serotypes S. Choleraesuis, S Typhimurium
Symptoms: primarily diarrhea
S. Choleraesuis - purplish areas in ears, rump, abdomen, high fever, death 1-3 days
Ovine Salmonellosis
Serotypes:
symptoms
Ovine Salmonellosis
Serotypes: S. Abortusovis - host adapted - causes abortion usually during last 2 months of pregnancy
S Typhimurium and S Dublin cause enteritis, septicemia and abortion (dublin - abortion)
symptoms
Can ine and Feline Salmonellosis
prevalence:
in greyhounds:
Can ine and Feline Salmonellosis
prevalence: clinical disease not common
in greyhounds: fromcontaminated raw meat
Avian Salmonellosis
Serotypes
Symptoms
what type of disease?
Who does it affect?
How transmitted?
Avian Salmonellosis
Serotypes S. pullorum causes Pullorum disease or "Bacillary White Diarrhea"
S. gallinarum causes Fowl Typhoid
both host adapted
what type of disease? septicemic
Who does it affect? primarily chickens and turkeys, rare in commercial poultry
How transmitted? through egg by transovarian infection
Avian Salmonellosis
S. pullorum
mortality: young v old
maintain orgainsm in?
Transmission?
Infection by? - causes?
Detect disease how?
Avian Salmonellosis
S. pullorum
mortality: young v old highly fatal in young chicks, older chicks more resistant, older birds carriers
maintain orgainsm in? ovaries
Transmission? transovarian
Infection by? - causes? inhalation highly infective: - caseous areas in lungs, ingestion - caseous areas in gizzard
Detect disease how? serologic tests
Avian Salmonellosis
S. gallinarum
causes:
Oranism maintained:
Transmitted: (2)
Signs:
Lesions:
Avian Salmonellosis
S. gallinarum
causes: fowl typhoid in chicken and turkeys
Oranism maintained: in ovary of carrier birds and
Transmitted: (2)
vertically (egg) or horizontally (feces or broken eggs), also by tick
Signs:inhalation leads to acute septicemic disease, weakens, hyperexcitability, paresis and diarrhea
Lesions: meningitis - multiple small necrotic areas in liver and heart
Avian Salmonellosis
National Eradication Program
outbreaks (3 steps)
Avian Salmonellosis
National Eradication Program
outbreaks (3 steps)
1) Pullorum and Fowl typhoid mandatory reportable in US
2) outbreaks placed under quarantine
3) periodic testing
4) esp in breeding flocks
Avian Salmonellosis
S. Typhimurium
Signs:
Significant:
Avian Salmonellosis
S. Typhimurium
Signs: often clinically inapparent, enteritis, diarrhea and septicemia in severe cases
Significant: is from subsequent contamination of chicken meat
Avian Salmonellosis
S. Anatum
causes:
Avian Salmonellosis
S. Anatum
causes: Keel disease in ducks
Salmonella
Diagnosis:
ID:
Immunity (2):
Vaccines (2):
Treatment:
Resistance?
Control Measures (3)
Salmonella
Diagnosis significance: Any time S. isolated, important either as cause of immediate problem or potential one
ID: of serotype : useful in poultry, exam blood or serum for presence of antibody
Immunity (2): humoral and cell mediated
IgA - local imunity
Serum IgG anbs against O-specidfic polysaccharide of LPS
Vaccines (2):
1) live, stimulate more effective cell0mediated immune response
2) Mutants using molecular techniques - e.g. auxotrophic mutants
Treatment: Abx valuable
Resistance? multible abx resistance common - must conduct sensitivity test
Tx of enteric disease with abx that S. is resistant to may result in production of systemic disease, and may increase lenght of time animal will shed organism and possibly result in a carrier animal
Control Measures (3)
1) reduce contamination of environment
2) eliminate source of infection
3) minimize stresses
Salmonellosis in Humas
3 syndroms (symptoms)
MDR Salmonella
2 serotypes importance:
Salmonellosis in Humas
3 syndroms (symptoms)
1) Typhoid fever - caused by S. Typhi, humans only reservoir, infrequent disease in US
2) Enteric fever - caused by S. Paratyphi A, S. Schottmuelleri and S. Hirschfeldii
3) Most common Gastroenteritis - contracted mainly through the consumption of raw or undercooked contaminated food of animal origin (meat, chicken, eggs and milk)
symptoms: diarrhea, abdominal pain
2 most common serotypes involved: S. Typhimurium and s. Enteritidis
MDR Salmonella: Multi-drug resistant Salmonella - major health concern
2 serotypes importance: DT104 and Newport - common in cattle and causing growing share of infection in humans
DT104 resistant to ampcillin, chloramphenicol, streptomycin, sulfonamides and tetracyclin, in last 100 years, killed 40% infected cattle, ground meat main source
DT104: beef, Newport: dairy
Newport - resistant: beta-lactam aintmicrobial agents: amoxicillin/clavulanate, ampicillin, cefoxitin, ceftiofur ceftriaxone, cephalothin, - attributable to plasmid, associated with dairy farms
Salmonella Summary
Species:
G?
Shape?
O2?
Lactose fermenter?
Antigens:
Serogroups:
Serotypes:
Salmonella Summary
Species: S. enterica (subsp, enterica)
G? -
Shape? rod
O2? facultative
Lactose fermenter? nonlactose fermenter
Antigens: O,H, and Vi
Serogroups: 50 groups (O antigen)
Serotypes: >2,300(O and H antigen)
Salmonella Summary
Serotypes adapted to:
Mode of infection:
Important predisposing factor:
Virulence factors:
Survives in:
Infections:
Salmonella Summary
Serotypes adapted to: host
Mode of infection: oral, transovarian in Chickens
Important predisposing factor: stress
Virulence factors: enterotoxins and endotoxin
Survives in: phagocytic cells
Infections: Intestinal (enterotoxins) and Systemic (endotoxin)
Salmonella Summary
Diseases:
(4)
Treatment: (important aspect)
MDR Salmonella:
Salmonella Summary
Diseases: Salmonellosis
(4)
1) enteritis
2) septicemia
3) abortion
4) food poisoning
Treatment: (important aspect) antibiotics (susceptibility testing needed)
MDR Salmonella: DT104 and Newport