Clostridia + Staphylococci

Page 1

Clostridia

Anaerobic

Varying

Gram negative

Produce spores

Under anaerobic conditions?Hetero genus

Most species have large battery of virulence factors

Largely saprophytic

Enzymes developed to break down

Disease

Neurotrophic

Enterotoxaemia's

Gas gangrene

Clostridium perfringens

Gas gangrene care

Virulence determinants

Major

Alpha

Beta

Epsilon

Iota

Enterotoxin (CPE)

Beta-2

NetB

Minor

Theta

Delta

Gamma

Kappa

Lambda

Mu

Nu

Sialidase

Double zone

Toxins and classifications

Epsilon toxin

Activated by trypsin

Plasmid encoded

Pore forming toxin

Increases vascular permeability in the intestines kidneys ...

Type D

Associated with pulpy kidney disease

Beta toxins

Heat labile pore forming toxin

Increase capillary permeability

???

Alpha toxins

Membrane damaging toxin

Haemolytic

Cytolytic

Necrotic

Essential with theta toxin for gas gangrene

Associated with necrotic enteritis in chickens

2-5 Weeks of age

extensive production losses world Wide

poor feed conversion rates

weight loss

Mortality 5 - 50%

Net B

Cytotoxic to a chicken LMH cells

Pore-forming toxin

netB mutant unable to cause NE

Outbreak strains carry netB

Necrotic enteritis in chickens

Treatment involves antimicrobials

NE often associated in co infection

Most models require confection with eimeria

Reduction in butyrate -producing strains

Diet

High protein

High viscosity diets

Non-digestible polysaccharides

Pulpy kidney disease

Typically cause by type D

Sudden death

Predisposing factors

Changes in diet

increase in food intake

Control and prevention

Vaccination

Neutrotoxins

???

Tetanus

slide 17??

cause?

Treatment

Antitoxin

Sedation

Antibiotics

Death -resp distress

Prevention

Vaccination

Botulism

7 toxinogenic types

Cause

Intoxication - ingestion of toxin

Often outbreak

Contamination of feed

Chicken litter

Illegal to be brought on to farms or fields

Effects

Sheep

Horses

Cows

Dogs

Rarely fatal for cats

Shaker foal syndrome

Infection in gut due to lack of competitive flora

??

Toxins

Similar to teNT but diff target cells

PNS

Stimulatory motor neurons

Weakness of flaccid paralysis

Symptoms similar to colic

Diff

Bot more comfy standing , Colic more comfy lying

No tongue reflex in Bot

Usually euthanised

Grass sickness

EQS fatal neurogenerative disease

More frequent occurring in UK

Acute EGS

Fatal/ requires euthanasia

Chronic

Weightloss or dysphagia

Intensive care

Encouragement of horse to eat

Poor prognosis

Risk factors

Ingestion of agent and prod of neurotoxins

Bot C main suspect

See slide 26

Other disease

Blackleg

Braxy

Malignant oedema

Vaccination

Summary?

Page 2

Staphylococci

Aerobic

Catalase postitive

Oxidase negative

Grow in NaCL concentrations

Coagulase +ve

More pathogenic

More virulent

S. aureus

S. pseudintermedius

?

Coagulase -ve

More antibiotic resistant

?

Often -ve and +ve occupy same niche

Nomads

???

Many found in diff animals

Preffered host species

Co-evolution

Will cross species barrier

Colonisation

Carriage

Infection

S. pseudintermedius

???

Pyoderma

Alterations of skin surface micro environment

Trauma

allergic skin disease or underlying skin disease

Breed associations

Skin folds

Largely superficial

Often treatment involves use of antimicrobial

Recurring

Treat underlying disease

Treatment ofre infections if underlying disease not treated

Medicated shampoos

Other diseases

Greasy pig disease

S.hyicus

Bumblefoot

Turkeys and chickens

S. gallinarum / S.aureus oother staph spp

S. aureus disease

Skin + soft tissue infection

???

Inasive infections

>???

Toxinoses

Due to production of toxins

Food poisoning

Scaled ski syndrome

Toxic shock syndrome

Virulence determinants

????

Stick - Adhesions

Surface proteins allow attatchment

fnbA fnbB

Promot adhesion to collagen

Clumping factor - Stick and stealth

Fibrin/Fibrinogen binding ???

Protein A - stealth

Surface associate protein

used for molecular typing

Capsuar polysaccharides

Potent access potentiators

Prevents phagocytosis

Important in mastitis

???

Immune evasion

Chemotaxix inhib protein

???

Other toxins

????

MRSA

Resistance conferred by mega gene

Alt penicillin binding protein

Encoded on a mobile gene cassette

Typing of isolates

???

Epidemiology in humans

nosocomial infections

two predominant strains

Community associated MRSA

In animals

Dogs ?

Horses ?

Livestock?

Resistant to ?

All B - lactam antimicrobials

Fluoroquinolons

MRSP

More multi drug resistance

Hospital acquired

Can be carried on mucosal surfaces for up to 11 months within hospitals

??

Resistant to?

see slide 56

What should we screen for MRSA/MRSP?

?

At risk patients

Dogs and cats

???

Horses

??

summary?