Changes in Holstein cow milk and serum proteins during intramammary infection with three different strains of Staphylococcus aureusReport as inadecuate

Changes in Holstein cow milk and serum proteins during intramammary infection with three different strains of Staphylococcus aureus - Download this document for free, or read online. Document in PDF available to download.

BMC Veterinary Research

, 7:51

First Online: 01 September 2011Received: 23 March 2011Accepted: 01 September 2011


BackgroundStaphylococcus aureus is one of the most prevalent pathogens to cause mastitis in dairy cattle. Intramammary infection of dairy cows with S. aureus is often subclinical, due to the pathogen-s ability to evade the innate defense mechanisms, but this can lead to chronic infection. A sub-population of S. aureus, known as small colony variant SCV, displays atypical phenotypic characteristics, causes persistent infections, and is more resistant to antibiotics than parent strains. Therefore, it was hypothesized that the host immune response will be different for SCV than its parental or typical strains of S. aureus. In this study, the local and systemic immune protein responses to intramammary infection with three strains of S. aureus, including a naturally occurring bovine SCV strain SCV Heba3231, were characterized. Serum and casein-depleted milk cytokine levels interleukin-8, interferon-γ, and transforming growth factor-β1, as well as serum haptoglobin concentrations were monitored over time after intramammary infection with each of the three S. aureus strains. Furthermore, comparative proteomics was used to evaluate milk proteome profiles during acute and chronic phases of S. aureus intramammary infection.

ResultsSerum IL-8, IFN-γ, and TGF-β1 responses differed in dairy cows challenged with different strains of S. aureus. Changes in overall serum haptoglobin concentrations were observed for each S. aureus challenge group, but there were no significant differences observed between groups. In casein-depleted milk, strain-specific differences in the host IFN-γ response were observed, but inducible IL-8 and TGF-β1 concentrations were not different between groups. Proteomic analysis of the milk following intramammary infection revealed unique host protein expression profiles that were dependent on the infecting strain as well as phase of infection. Notably, the protein, component-3 of the proteose peptone CPP3, was differentially expressed between the S. aureus treatment groups, implicating it as a potential antimicrobial peptide involved in host defense against S. aureus intramammary infection.

ConclusionsIntramammary infection of dairy cattle with S. aureus causes an up-regulation of serum and milk immune-related proteins, and these responses vary depending on the infecting strain.

Electronic supplementary materialThe online version of this article doi:10.1186-1746-6148-7-51 contains supplementary material, which is available to authorized users.

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Author: Yunee Kim - Heba Atalla - Bonnie Mallard - Claude Robert - Niel Karrow


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