Bacteria
on
the
skin
and
in
milk
of
ewes
The pathogenesis of mastitis in ewes
Cooper.S1*, Purdy.K.J1, Bradley.A.J2, Green.L.E1
1School
of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL
2QMMS Limited, Unit 1, Lodge Hill Trading Estate, Westbury-sub-Mendip, WELLS BA5 1EY
*selin.cooper@warwick.ac.uk
o Mastitis is a disease that occurs when a bacterial infection in the udder causes inflammation
o Serious economic and welfare implications
o Little is known about when and how the udder becomes infected and whether certain strains of
bacteria are responsible for disease
Aim: To identify and compare strains of the same species of bacteria on the skin of the udder and from
the milk of ewes with and without clinical mastitis
o Samples were collected from 28 clinically affected ewes, and 3 ewes without clinical signs
o Matrix Assisted Laser Desorption Ionisation Time of Flight Mass Spectrometry (MALDI-ToF-MS) to identify bacterial species
o Pulsed Field Gel Electrophoresis (PFGE) to identify strain types
Run on
PFGE gel
Run bacteria on
MALDI-ToF
analyser
Grow and sterile
streak bacteria
Bradley and Green (2000)
Photograph courtesy of Selene Huntley
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Bacterial species in mastitic milk
20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
5.0
Udder skin
4.5
Mastitic milk
Percent of isolates on udder skin (%)
Percent of isolates in mastitic milk and on udder skin
(%)
Percent of isolates in mastitic milk (%)
8.0
0.0
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Bacterial species in both mastitic milk and udder skin samples
o Differences in the bacterial species present on the udder skin and in mastitic milk
o Certain genera of bacteria, such as Staphylococcus, are present in milk and on udder skin
o This suggests that udder skin is a possible reservoir for mastitis causing pathogens
Bacterial species on udder skin only
o PFGE isolates of
interest
oLongitudinal studies
throughout lactation
1. A Study of the incidence and significance of intramammary enterobacterial infections acquired during the dry period A.J. Bradley, M.J. Green Journal of Dairy Science 1 September 2000 (volume 83 issue 9 Pages 1957-1965)