Bacterial species and their associations with acute and chronic mastitis in suckler ewes.
Acute mastitis in suckler ewes is often detected because of systemic signs such as anorexia or lameness, whereas chronic mastitis, characterized by intramammary abscesses with no systemic disease, is typically detected when ewes are inspected before mating. The aims of the current study were to identify the species and strains of culturable bacteria associated with acutely diseased, chronically diseased, and unaffected mammary glands to investigate whether species and strains vary by state. To investigate acute mastitis, 28 milk samples were obtained from both glands of 14 ewes with acute mastitis in one gland only. To investigate chronic mastitis, 16 ovine udders were obtained from 2 abattoirs; milk was aspirated from the 32 glands where possible, and the udders were sectioned to expose intramammary abscesses, which were swab sampled. All milk and swab samples were cultured aerobically. In total, 37 bacterial species were identified, 4 from acute mastitis, 26 from chronic mastitis, and 8 from apparently healthy glands. In chronic mastitis, the overall coincidence index of overlap of species detected in intramammary abscesses and milk was 0.60, reducing to 0.36 within individual glands, indicating a high degree of species overlap in milk and abscesses overall, but less overlap within specific glands. Staphylococcus aureus was detected frequently in all sample types; it was isolated from 10/14 glands with acute mastitis. In 5 ewes, closely related strains were present in both affected and unaffected glands. In chronic mastitis, closely related Staphylococcus aureus strains were detected in milk and abscesses from the same gland.
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom. Electronic address: edward.smith@warwick.ac.uk.
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Smith
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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Willis
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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Blakeley
University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, United Kingdom; Flock Health Ltd., Balmer House, Eggleston, Co. Durham, DL12 0AN, United Kingdom.
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Lovatt
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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Purdy
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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Green
D000208:Acute Disease; D000818:Animals; D000833:Animals, Suckling; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification*; D002908:Chronic Disease; D005260:Female; D008321:Mammary Glands, Animal / Q000382:microbiology; D008413:Mastitis / Q000382:microbiology / Q000662:veterinary*; D008892:Milk / Q000382:microbiology; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology*; D034561:Sheep, Domestic; D013203:Staphylococcal Infections / Q000662:veterinary; D013211:Staphylococcus aureus / Q000302:isolation & purification
Staphylococcus aureus; acute mastitis; chronic mastitis; matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF); suckler ewe