Staphylococci

Question 1

Intrammary mastitis and types of it

Answer 1

Udder cavity of ruminants invaded by bact causing inflam
Subclinical (incr SCC)
Clinical (mild and acute) inflam tender swelling clots in milk
Peracyte very severe systemic inflam gangrenous fever possibly fatal

Question 2

Wound infections

Answer 2

Abscesses
Pustules
Various species as opportunistic

Question 3

Pyoderma

Answer 3

Esp dogs
Commonly pseudintermedius as 2o factor after dam by allergy or parasites
And folliculitus

Question 4

Tuck pyemia

Answer 4

Infection after dam by ticks esp ixodes ricinus

Abscesses in joints and other tissues

Question 5

Exudative epidermitis (greasy pig disease)

Answer 5

Hyicus

Highly contagious and acute generalised skin infection in young animals

Question 6

Dermatitis
Osteomyelitis
Arthritis

Answer 6

Poultry

Usually aureus

Question 7

Cystitis

Answer 7

Esp dogs and cats
Paeudintermedius
Aureus

Question 8

Septicaemia

Answer 8

Many animals incl rabbits

Question 9

Infective endocarditis

Answer 9

Horse
Cow
Large breed dogs

Question 10

Economic implications of mastitis

Answer 10

Cost uk farmers approx 93 mill a yr
USA approx 2 bill a yr
Clinical cases 1/5 of what they were in the 60s and sub clin (predominant form) also decr

Question 11

Mastitis pathogenesis

Answer 11

Can colonise teat for long time periods
Penetrate teat duct with milk as a good nutrient source
Adherence to epi cells probs v important

Question 12

Adherence virulence factors and why adherence important

Aureus

Answer 12

To initiate infection must access and attach to host cells or tissues
MSCRAMMs
Expr surf pros that attach to host pros like fibronectin and laminin in the ECM
Fibronectin also on epi and endo cells and a blood clot comp
Most strains expr clumping factor A a pro that binds fibrin/fibrinogen to promote attachment
Also most expr other fibrinectin/ogen bind pros and Fn binding pros med cell invasion

Question 13

Capsular polysacc host D avoidance virulence factor of aureus

Answer 13

Most clinical isolate expr 5 or 8
Microcapsile as only viewed via electron microscopy after Ab labelling
Rapidly lose high polysacc level up in vitro culture from in vivo
Capsule res phagocyt
Serotype vary with strain

Question 14

Staph pro A host D avoidance virulence factor of aureus

Answer 14

Surf pro that bind IgG by Fc region

Bind wring way round so disrupt opsonisation and phagocyt

Question 15

Superantigens host D avoidance virulence factor of aureus

Answer 15

Stim T cells non-spec without normal antig recog
So cytok released in high amounts- detrimental to host and contrib to modulationof hist resp
Bind direct to MHC c2 of APC outside normal antig bind groove so complex recog on Vb element of T cell rec, so any T cell with matching Vb is stim, normal complex would also req antig spec in binding

Question 16

Mem damaging alpha tox of aureus

Answer 16

Most potent mem dam tox
Expr as monomer and bind mem of susceptible cells
Subunits oligomerise and form hexameric rings with central pore

Question 17

Beta toxin of aureus

Answer 17

Sphingomyelinase that dam mem rich in sphingomyelin
Test for this tox is sheep RBC lysis
Most human strains dont expr beta tox
Most mastitis strains do so thought to be important in mastitis pathogenicity

Question 18

Delta tox of aureus

Answer 18

Small peptide tox prod by most strains of aureus
Also by epidermidis and lugdunensis
Has cytolytic activity

Question 19

Gamma tox and leukocidins

Answer 19

Two component pro toxins that dam susceptible cell mem esp PMN

Question 20

Aureus enzymes that are virulence factors

Answer 20

Proteases
Lipase
DNase
All provide nutrients, minor role in pathogenesis
FAME (fatty acid modifying enz)
Important in abscess as could modify antibact lipids and prolong bact survival

Question 21

Varying host genetic susceptibilities and determinants for mastitis

Answer 21

SCC
Lactoferrin
Lysozyme
MHC
Udder depth
Milking speed
Milk production traits

Question 22

Control of mastitis

Answer 22

Hygiene
Udder and teats washed pre milk
Disinfect post milk
Regularly clean and sterilise and service milking equip

Question 23

Mastitis treatment

Answer 23

Antibio therapy
Residues must be cleared before milk consumption
Res increasing
In vitro efficacy not a good predictor
Use IL therapy?

Question 24

Poultry infection

Answer 24

Aureus cause joint infection eg septic arthritis and BCO

Question 25

Canine pyoderma what is it

Answer 25

Pseudintermedius (methicyllin res does exist) Common skin disease often 2o to atopic dermatitis - usually commensal

Question 26

Canine pyoderma symptoms

Answer 26

Pruritus
Alopecia
Swelling
Erythema

Question 27

Canine pyoderma treatment

Answer 27

Systemic antibios and topical shampoo

No effective vacc

Question 28

S delphini

Answer 28

Assoc with horse pyoderma

Question 29

S intermedius

Answer 29

Assoc with pigeon pyoderma

Question 30

Exudative epidermitis symptoms and causative bact

Answer 30

Oozing fluid from inflamed skin
Hyicus - normally commensal but cause disease after abrasions. Produce exfoliative toxins causing skin lesion symptoms and liver and kidney dam
If liver dam then fatal

Question 31

Exudative epidermitis epidemiology

Answer 31

Bact multiply in sows vagina days immediately pre farrowing and piglets often infected during or just after birth

Question 32

Exudative epidermatitus treeatment

Answer 32

Antibio and inject daily for 5 days or with long acting antibio on alternate days
If sever outbreak an autogenous vacc can be prepped from org and has been effective on some farms