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87 Cards in this Set

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How are the family Enterobacteriaceae divided?
28 Genera - by morphology, biochem & DNA relatedness

128 Species - bichemistry & DNA relatedness

Strains
serotyes - antigens
biotypes - biochemisty
these two relate to divergence from common ancestor
Phagetypes - random division method
PCR - not used as muach as could be as does not follow spp's biochem divisions
What pathogenic genera are contained in the Enterobacteriaceae family?
Morganella
Serratia
Citrobacter
Edwardsiella
Enterobacter

more imp
Klebsiella
Shigella
Proteus
Esherichia
Salmonella
Yersinia
Which four Enterobacteriaceae are important when considering VPH?
Salmonella
E. coli
Yersinia
Shigella
How would you go about initially isolating & catergorising Enterobacteriaceae?
Grow on Fresh blood agar & MacConkey bile lactose agar plates under aerobic & anaerobic conditions.
(bile lactose differentiates lactose fermentors)
Why grow clinical sample on both Blood agar and MacConkeys Bile lactose agar plates?
Blood agar non selective

MacConkeys - selective for Enterobacteriaceae, as tolerate bile and differentiates lactose fermentors.
What is the significance of the colour changes on this MacConkey bile lactose agar plate?
What is the significance of the colour changes on this MacConkey bile lactose agar plate?
Lactose fermentation = acid prod = RED
- LAC+ve, coliforms -pink
E.coli, Klebsiella, Enterobacter

AA decarboxylation = alkali = YELLOW
- LAC -ve, non coliforms - yellow
Salmonella, Shigella, Proteus, Yersinia
List general differential features of Enterobacteriaceae family.
Grow in presence of bile
Non sporing
Facultative anaerobes
med sized (0.3-1 x 1-6uM)
List general non differential features of Enterobacteriaceae family.
All Gram -ve, straight rods
some motile, some not (peritrichous flagella)
med sized (0.3-1 x 1-6uM)
both catalase +/-ve spp
Simple nutritional needs.
Salmonella selective media such as brilliant green agar (brown) as it is ---------- of other Enterobacteriaceae & differential.
Coliforms = ?
Non coliforms = ?
suppressive

yellow / green
mostly red
Enrichment broths use toxic agents such as -------- or ------------ which are ----- to different ---- to select one wish to grow.
Selenite (salmonella selctive), tetrathinate

toxic

spp
What colony morphology is seen in this growth on a BLA?

What is it indicative of species wise and why?
What colony morphology is seen in this growth on a BLA?

What is it indicative of species wise and why?
Small butyrous like dk pink colonies

E.coli

Klebsiella & Enterobacter
colonies are larger, mucoid and pale pink
The IMViC test pattern seen above is indicative of  which enteric bacteria?
The IMViC test pattern seen above is indicative of which enteric bacteria?
E. coli

Klebsiella & enterbacter are -ve for I & M & +ve for Vi & C
What do the initials IMViC stand for?
What do the initials IMViC stand for?
Indole
Methyl Red
Voges Proskauer
Citrate
The IMViC test pattern seen above is indicative of  which enteric bacteria?
The IMViC test pattern seen above is indicative of which enteric bacteria?
Klebsiella & enterbacter

E. coli are +ve for I & M & -ve for Vi & C
How must you grow your bacteria to test for motility by the hanging drop method and which genus of enteric coliform bacteria can be differentiated from one another post an IMVic test by this method?
Must be grown in broth

Klebsiella -ve motility

Enterbacter +ve motility
How would you proceed from genus ID to species level?
Lysine decarboxylase & urease tests.
The urease, H2S & lysine decarboxylase tests  can be used to distinguish both -------- & --- -------- genus of enteric bacteria.
The urease, H2S & lysine decarboxylase tests can be used to distinguish both -------- & --- -------- genus of enteric bacteria.
coliform & non coliform

Urease H2S Lysine decarboxylase
Shigella - - -
Salmonella - most + most +
Proteus + most + most +
Yersinia + - -
Combination media as seen above have speeded identification, they use TSI or XLD what is this?
Combination media as seen above have speeded identification, they use TSI or XLD what is this?
Triple sugar Iron agar
Xyline, Lysine, Deoxycholate agar
If you saw this on a plate what genus of non coliform enteric bacteria would you know is present?

What else would confirm this identification?
If you saw this on a plate what genus of non coliform enteric bacteria would you know is present?

What else would confirm this identification?
Proteus - as it swarms across BA plate (not MacConkeys)

Smell

note of caution it may obliterate other growing colonies of diff spp/ genus
Which non coliform enteric bacteria are motile and non motile?
Motile Non motile
most Salmonella shigella
Yersinia @22deg C Yersinia @ 37deg C

change in motility may reflect dislike of conditions.

Chicken salmonella spp lost motility.
The image above shows a XLD agar plate what does this distinguish between?
The image above shows a XLD agar plate what does this distinguish between?
Fermentation method - red if acidic

Black = H2S production

lysine decarboxylase activity

deoxycholate - bile sensitive so restricts to enteric
What tests would be used to further  speed up / identify pathogen spp?
What tests would be used to further speed up / identify pathogen spp?
Commercial biochemistry kits as shown in image
quick 4hrs growth in media post 24 hour isolation plate

Immunological - ELISA /RIA
but requires an idea of what expecting to see

Genetic tests
not commonly used , only major pathogens
[DNA] limiting
Regional reference labs will -------- enteric bacteria.

What Ag are there for E.coli and Salmonella respectively?
serotype

O, H, K, & F

O, H.
Where are E. coli O, H, K & F Ag located?
O = sugar side chain of LPS (>170)

H = flagellar protein (>56)

K = capsular polysaccharide (>80)

F = fimbrial proteins

serotype designations are V specific, >1000
i.e. O139: K82 : H2
Which O serotypes of salmonella are pathogenic to animals?
A-I

agglutination with Ab = +ve

i.e. S. enteriditis O;1,9,12 H (comensal )
What would be a better approach / more logical to strain identification of bacterial spp then serotyping?
Genetic testing for toxicity genes
as specific toxin is related to dz seen & treatment.
What is the relevance of using polyvalent O & H antiserum?
polyvalent O antiserum contains all animal pathogenic Ag's so +ve = pathogenic

polyvalent H antiserum contains all H Ag's
agglutination = +ve for motility
so know not chicken spp salmonella
Monovalent O & H antisera +ve agglutination allows….
individual strain id

H antisera identifies diff flagella types
some salmonella strains capable of switching type for immune avoidance.

Chickens spp non motile =>> pathogenicity
Enteriditis = 1 type of flagella
Others 2 types of flagella.
What system of salmonella classification is currently used?
Le Minor & Popoff Scheme
1 spp - S.enterica

Bergey's Manual 1994 -
2 spp - S. enterica
-S bongori (10 serotypes, non path & reptile)
Name one enteric bacterial obligate pathogen that causes dysentery in humans & primates?

How is it identified
Shigella
S. sonneri & S. flexneri most common
incubation 1-7 d, usually 48hrs

O serotype & toxin assays
How is Shigella pathogenic?
Attaches GIT epithelium @ M cells of peyers patch
induced endocytosis from GIT epithelium
invasion of lymph nodes via macrophages engulfing
escape lysis by prevention of acidification of vacuole

Toxin
Shiga toxin - reduces protein synthesis S. dysenteriae
Endo toxin -increases vascular permeability,
inflammation & fever
- water loss / red water reabsorption
How is shigella spread, treated and prevented?
in fecal matter
carrier status can last for months in humans

supportive therapy - fluid replacement
antibiotics highly ?? as self limiting
vaccination, reduce spread & improve hygiene
Proteus is a human / animal GIT commensal where else is it found  and what diseases is it important in ?
Proteus is a human / animal GIT commensal where else is it found and what diseases is it important in ?
soil & water

Otitis externa - dogs & cats, v v common
UTI - dogs & Eq
Diarrhoea - young most spp
Surgical problems - GIT contents spillage
What 2 spp of Proteus are commonly seen in vet  medicine?
What 2 spp of Proteus are commonly seen in vet medicine?
P. vulgaris & P. mirabilis
What virulence determinants are important in Proteus infections?
What virulence determinants are important in Proteus infections?
Adhesins & Endotoxin possibly not definitively known

Urease imp in bladder infections
- alters pH causing epithelium damage
What serotypes are used to Id proteus strains?
What serotypes are used to Id proteus strains?
O & H
How would you treat / prevent Proteus infections?
How would you treat / prevent Proteus infections?
Antibiotics

No vaccines

Hygiene / aseptic technique
Klebsiella pneumoniae is found in whiat spp and where?
Klebsiella pneumoniae is found in whiat spp and where?
humman & animal

GIT commensal

also soil, water, hands, instruments

Mucoid on plate
Important Klebsiella pneumoniae dz include….
Important Klebsiella pneumoniae dz's include….
Wound infection
- joint navel, foals & lambs
- wounds in man

Mastitis - post parturition esp on wood bedding

UTI's - dogs
Pneumonia - foals
Genital tract infection - horse
- male short term
- female long term & abortion
Virulence determinants in Klebsiella pneumoniae are
Virulence determinants in Klebsiella pneumoniae are
Fimbrial adhesins
Capsule
Endotoxin
Siderophore
Steric hindrance of complement

Mucoid on plate
What serotypes are used to Id Klebsiella pneumoniae strains?
What serotypes are used to ID Klebsiella pneumoniae strains?
K 77-82

Mastitis - many K Ags
Meritiis - 1, 5 & 7 (mares)
Pneumonia - 1, 2 & 3 (humans)

Mucoid on plate
How do you treat / prevent Klebsiella pneumoniae?
How do you treat / prevent Klebsiella pneumoniae?
Antibiotics

No commercial vaccine

Hygiene, good aseptic technique

Mucoid on plate
Where is Yersinia pseudotuberculosis found, spp etc?
Where is Yersinia pseudotuberculosis found, spp etc?
soil - worldwide

GIT - wild mammals esp rodents,
- birds,
- domestic animals
In what spp / locations are Yersinia pseudotuberculosis commonly seen?
In what spp / locations are Yersinia pseudotuberculosis commonly seen?
Captive rodents / birds
Zoo animals
Humans
Domestic animals

(stress related?)
How does Yersinia pseudotuberculosis present, what serotypes are used to ID and how is it treated / prevented?
How does Yersinia pseudotuberculosis present, what serotypes are used to ID and how is it treated / prevented?
TB like - caseous lymph nodes,
- necrotic lesions in lung

O & H serotypes

Antibiotics

No commercial vaccines
Rank in order of virulence
S. flexneri
S. dysenteriae
S. boydii
S. sonnei
S. dysenteriae - most Shiga toxin, most severe gastroenteritis
S. boydii & S. flexneri - less toxin, less severe
S. sonnei
What is Y. enterocolitica imp in VPH and why this spp?
main source of food poisoning from pigs.
can proliferate at fridge temps (better then listeria)
O3 & O9 serotypes most common

Specifically inhabits pig tonsils !!
less common also in soil & GIT of domestic & wild spp.
What are the virulence determinants for Yersinia pseudotuberculosis & Y. enterocolitica?
GTPase regulator
attachment
invasion
superantigens - stimulate T cells - cytokine release
opsinisation neutralisation

Y. enterocolitica only
het stable enterotoxin
How does Y. enterocolitica cause disease?
As Yersinia pseudotuberculosi

Bacteria adhere to gut mucosa, destroys cells lining the gut. An enterotoxin (YST), which is stable in hot (121oC) and cold conditions, is produced but its role is unknown. Results in relatively mild infection (5-14 days), abdominal pain (pseudo-appendicitis), fever, diarrhoea; nausea and vomiting rare; but can cause septicaemia in the immuno-compromised.
What serotype would you ID Y. enterocolitica strains by
O

O8 & 9 - humans
O9 - also Brucella abortus
How would you treat Y. enterocolitica infections?
Antibiotics
may cull due to persistence

No commercial vaccine availabe
E. coli dz's spread via ------ ----- contamination.

They are both ---------, obligate & ------------- pathogens
Faecal oral

commensals, obligates & opportunistic
E. coli is commonly seen in the following dz's
Wound infections
surgical problems
UGT infections
Udder infections

Mastitis
most common G-ve cause
V common & serious
E. coli is a non specific dz because….
endotoxin damages teat reducing milk yield for months.
Obligate pathogenic E.cloi is associated with 2 types of dz what are they and there modes of action?
Enteritits and / or Septicaemia

Ingestion Ingestion
Diarrhoea Invasion -> shock ->Death <2d
Dehydration Deposition, joints, meningies
Death <3 days Death < few days
E. coli Enteritis / septicaemia dz types are affected by…...
Serotype
some -> enteritis only
some -> enteritis & septicaemia
some -> septicaemia only

Host spp

Predisposing factors
age / immunocompromised
newly weaned (maternal Ab loss)
poor hygeine
What 6 categories of obligatory pathogenic E-coli serotypes are there?
ETEC - Enterotoxigenic - toxin producing

VTEC - Verotoxigenic (VHEP in humans) bloody diarrhoea

AEEC - Attaching & Effacing

EIEC - Enteroinvasive

Unclassified

Necrotoxigenic - new high mortality rate
What serotypes are expressed by ETEC E.coli?
ETEC binds to Fimbrial adhesins found on GIT colonic epi cells
host spp expression variation = strains host specificity
i.e F4 (K88) - piglets & horses
F5 (K99) - piglets, calves, lambs
What common dz's are caused by ETEC and in what spp?
see image
see image
What specific enterotoxins are associated with ETEC E. coli?
ST - heat stable

LT - heat labile

affect Na pump = watery diarrhoea as reduces H2O reabsorption.
What serotypes are expressed by VTEC E.coli?
VTEC binds to Fimbrial adhesins & pther adhesins found on GIT colonic epi cells
What specific enterotoxins are associated with VTEC E. coli?
Verotoxins - shiga like 
    VT1, VT2 & VT2e
    VT2e - face and neck swelling
        prevent protein production in host cell of membrane bound proteins => red H2O reabsorption.
Verotoxins - shiga like
VT1, VT2 & VT2e
VT2e - face and neck swelling
prevent protein production in host cell of membrane bound proteins => red H2O reabsorption.
What common dz's are caused by VTEC E.coli in what spp?
post weaning piglets -
weanling enteritis; as for ETEC but less common

oedema disease; quite common;
acute and chronic forms; high mortality;
N.B. no enteritis

Calves 1-7d - white scours; as for ETEC

Rabbits - enteritis; common; high mortality
What common dz's are caused by AEEC E.coli in what spp?
enteritis - rare; some deaths
What common dz's are caused by EIEC E.coli in what spp?
Calves - septicaemia; high mortality

Lambs (1-3d) - septicaemia (watery mouth); hi mortality

foals - septicaemia; common, hi mortality, 25% all deaths
What common dz's are caused by unclassified E.coli?
Mushy chick dz - egg infected in ovaries or post laying
total body inflammation = fatal

Chicken septicaemia - inhalation of faecal matter
- invasion from lung to blood
- acute form high mortality
- chronic granulomatous dz
intestines / mesentery
Hjarre's dz's
What virulence factors are used by AEEC E. coli?
Fimbrial attachment
Intimin & Initimin receptor
toxins ??? not yet identified
What virulence factors are used by EIEC E. coli?
Adhesins
Surface proteins - parasite induced endocytosis / uptake
Enzymes - escape endosome
Capsule / outer membrane proteins
limit phagocytosis & opsinisation
Siderophores
Endotoxin
over activate Complement
Toxic shock
Death of young
Obligate pathogenic E. coli infections are ID'd by….
Fimbrial Ag & toxins
Fluorescent Ab tests & PCR
Obligate pathogenic E. coli infections are treated by …...
Antibiotics where not resistant

Palliative - fluid / electrolyte therapy
Obligate pathogenic E. coli infections are prevented by….
Good husbandry
susceptible to UV, drying & disinfectants

Vaccines ( fimbrial proteins /toxins)
Neonate; passive or active immunisation
Salmonella reservoirs incude….
GIT humans, mammals, birds, reptiles
Salmonella serotypes are ---- adapted & --- ---- adapted.

Adaptation is --- ------
host, non host
i.e. host adapted - S. Dublin, S. Pullorum
non adapted - S. Typhimurium


not absolute
almost all serotypes can affect humans excpet poultry adapted, S.pullorum
Salmonellosis can be either --------- or -----------
Enteritis or septicaemia
Enteritis salmonellosis manifests via…..
Motility leads to contact
Fimbrial mediated adherence
Parasite induced endocytosis, inflammation
Endosome survival - catalase activity
Endotoxin & cell damage
Adenylate cyclase activation & inflammation
cellular infiltrate large
Septicaemic salmonellosis manifests via…..
Fimbrial mediated adherence
Parasite induced endocytosis, inflammation
Endosome survival - catalase activity
Deeper invasion - blood stream
Endotoxic shock, +/- deposition
Joints -arthritis / osteomyelitis
Placenta / foetus - abortion
Brain - meningitis
Lungs - pneumonia

edotosaemia induced ischaemia in claves hind limbs/ tail/ ears = terminal dry gangree in calves
The type of dz seen in salmonella infections depends on ….
Virulence determinants

Innate & adaptive host defences

Interaction of these factors

Primary infection

subclinical | clinical
|
chronic recover | local invasive
| enteritis septicaemia
sub clinical clinical |
shedders
What sources of Salmonella infection in animals are ther?
Environmental

Milk from carriers

Infected hosts / convalescent hosts / carriers

Vertical transmission from infected breeding stock
How do Salmonella outbreaks occur?
not common

an individual infected animal joins susceptible herd / flock

Contaminated feed / water
shedding from rodents
protein supplements - most common source
How does Salmonella spread in reptiles & birds differ?
Fecal - oral spread

vertical transmission - via eggs

Salmonella diverged from E.coli @ dinosaur point in evolution.
Human Salmonella infections in humans are usually ...
Food borne
infected source animal / bird
infected food handler / utensils

S. Typhimurium - in all spp
S. Enteritidis - in poultry

Beware imported eggs & poultry not vaccinated.
Salmanellosis is diagnosed by what types of testing?
Biochemical
Serotypes
Biotypes
Phage types
Flourescent Ab staining of faecal matter / PM tissues
In Salmonellosis fecal samples are often -----------
polymorphic
To carry out serological testing ideally you need to do ----- / ----------- tests and carry these out against ------ sera from both ----- & ------------ stages or the dz. Ideally you would test the ---- not ---------.

The problem with single sera testing is…..
ELISA / agglutination

paired

acute & convalescent

herd / flock not individuals

Gives many false +ve
How would you control Salmonellosis in animals?
Good husbandry
Vaccines - inactivated & live
Competitive exclusion
- feed pooh from herds / flocks free of dz causing
How would you control Salmonellosis in humans?
Break chain of infection
clean water
food hygiene
sewage disposal
What similarities & differences are there in treating enteritic & septicaemic Salmonellosis?
Similarities
good nursing
Fluid / Electrolyte replacement

Differences
Enteritis
- antibiotics probably contra indicated in enteritis as selects for inc resistant & inc virulence salmonella strains & kills comensals

Speticaemia
Antibiotics indicated, parenteral admin