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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #196233
Title: BACTEREMIA NOT DETECTED DURING EXPERIMENTAL COLIFORM MASTITIS INFECTION

Author
item Goff, Jesse
item SPRINGER, HAYLEY - IOWA STATE UNIVERSITY
item Bannerman, Douglas
item Paape, Max

Submitted to: Joint Meeting of the ADSA, AMSA, ASAS and PSA
Publication Type: Abstract Only
Publication Acceptance Date: 2/18/2006
Publication Date: 7/9/2006
Citation: Goff, J.P., Springer, H.R., Bannerman, D.D., Paape, M.J. 2006. Bacteremia not detected during experimental coliform mastitis infection [abstract]. American Dairy Science Association-American Society of Animal Science 2006 Joint Annual Meeting. p. 11.

Interpretive Summary:

Technical Abstract: A bacteremia, caused by diverse species, was associated with about one third of acute coliform mastitis cases occurring in a field study report. However, blood is typically a very hostile environment for bacteria. Using blood from normal cows we demonstrate that when 2000 CFU of Escherichia coli or Staphylococcus aureus were added to 1-ml blood, more than 97% of bacteria were killed within 3 h, suggesting normal blood cells are efficient at killing bacteria entering the blood. However, this may not be the case during acute mastitis. We tried to recreate the field conditions by inoculating one quarter of the udder of 20 cows with 220 CFU E. coli, which caused an acute mastitis with bacteria and somatic cell counts in the milk each exceeding 1million/ml milk. Rectal temperatures were elevated by 18 h in all cows (P < 0.05) and remained elevated for another 18 h. E. coli infection caused an acute decline in blood neutrophil and lymphocyte numbers and neutrophil function by 24 h of infection (P < 0.05), which could be indicative of generalized immune suppression. All cows cleared E. coli from milk without treatment in 5-10 d. Blood (1 ml) obtained asepticly at 0, 6, 12, 18, 24, 30, 36, 48, and 60 h of infection from each cow was added to 10-ml Brain Heart Infusion Broth and incubated for 48 h. With the exception of 2 cultures suspected of Bacillus sp. contamination, all other cultures were negative for aerobic growth, despite evidence of systemic challenge to the immune system. Bacteremia does not appear to be common in coliform mastitis, especially in cases where animals are able to recover on their own.