Mastitis pathogens Flashcards
What are the different grades of mastitis?
*Sub-clinical
*Grade 1 - mild
*Grade 2A - acute
*Grade 2C - chronic
*Grade 3 - gangrenous mastitis
What are the contagious pathogens?
*Staphylococcus aureus
*Streptococcus dysgalactaie
*Streptococcus agalactiae
*Coagulase negative Staph. spp
*Mycoplasma spp.
What are the environmental pathogens?
*Streptococcus uberis but also cow adapted strains
(contagious)
*Coliforms e.g. Escherichia coli, Klebsiella pneumoniae
How can you identify a bacterial infectioin?
*Culture
*PCR
What are the reasons for sample failure?
- Contamination
- Testing panel
- Not shedding
- Poor storage/handling
- Unknown pathogen
What are the features of Staph. aureus?
- Gram positive cocci
- Coagulase positive
- On blood agar, white colonies with a ring of haemolysis
How do you control Staph. aureus?
1 *Prevent introduction of new infection
2 Reduce existing infection in herd:
* Treat cases
* Cull chronic cases
* Dry Cow Therapy
3Prevent spread within herd
* Milking parlour
*Wear Gloves
*No common udder cloths/ wipes
*Early detection and treatment
*Post milking teat disinfection
*Milking order
What are the features of Strep agalactiae?
- Gram positive cocci
- Non-haemolytic
- Very small pin prick
colonies
What grade of mastitis is strep agalactiae?
*Subclinical
*Grade 1 & 2
What pathogens are resistant to penicillin?
*Staph aureus
*Mycoplasma
What pathogens are treated by penicillin?
*Strep agalactiae
*Strep dysgalactiae
*Coagulase Negative Staphylococci
What are the features of strep dysgalactiae?
- Gram positive coccus
- Small pin point colonies
on Edwards Medium
Partial Haemolysis
Green Zone - Alpha haemolysis
What is a source of infection in strep dysgalactiae?
*Udder, teat skin particularly when skin damaged, tonsils
and so cows and heifers licking each others teats
important
What are features of Mycoplasma species?
- Often produce marked milk drop and swollen quarter
although the cow is not systemically ill - Highly contagious in parlour , aerosol spread and
haematogenous
*SHED FOR MONTHS AND MAYBE LIFE
Why shouldn’t you feed mycoplasma contaminated milk to calves?
*Pneumonia
*Otitis
How do you control Mycoplasma infection?
– affected cows often culled
– milking order (affected cows milked last)
– Disinfect cluster thoroughly etc. to stop spread
What are the features of E.coli?
- Blood agar forms
creamy white colonies - Haemolytic and non
haemolytic - Gram negative rods
Where do cattle pick up E.coli from?
*bovine faeces
* Housed = risk factor
* Build up of infection over housing period
What are the clinical signs of Grade 1, 2A and 3 of E.coli mastitis?
Grade 1
clots in milk (self cure)
Grade 2A
clots in milk, hard hot painful quarter
Grade 3 - COMMON
Very sick cow, endotoxaemic shock (usually post calving peri-parturient immunosuppression) udder variable can be cold or hot, hard or soft,
Milk varies from clots to blood
Important differential for downer cow post calving
How do you control E.coli mastitis?
- Infection particularly common in dry period and early lactation
- Pre-milking teat preparation– Remove the muck!
- Loafing times post milking
- Appropriate Dry Cow Therapy
- Vaccination – “Startvac”
What are the features of Streptococcus uberis?
- Non haemolytic
- Brown colonies on
Edwards medium - Gram positive
What is the source of strep uberis?
Bovine faeces
* Straw yard housing
* Straw bedded cubicles
* Muddy fields at end of summer / crowded shade
How do you control strep uberis?
– Pre-milking teat preparation
– Milking order
– Cull chronic cases
– Dry Cow Therapy
What are examples of other environmental pathogens?
- Klebsiella spp
- Bacillus cereus and licheniformis
- Pseudomonas spp
- Yeasts (Candida spp)
What does summer mastitis tend to affect?
- Typically affects DRY cows and HEIFERS OUT DOORS IN SUMMER in fields
*but is also seen occasionally in
steers and bulls and can occur in housed cows in
winter
What are the pathogens of summer mastitis?
*T. pyogenes
*Peptococcus indolicus *Strep dysgalactiae
*Bacteriodes melaninogenicus
*Fusiformus necrophorum
What is the fly that spreads summer mastitis?
Hydrotea irritans
Sheep head fly
What is the typical clinical sign of summer mastitis?
*Hot, hard, swollen, painful udder
*Cow may also be lame + systemically ill
What is the milking order to minimise mastitis transmission?
- 1st parity heifers first
- Healthy cows next (SCC low)
- High SCC cows
- Cows with clinical mastitis
