title: Mastitis Pathogens with High Virulence in a Mouse Model Produce a Distinct Cytokine ProfileIn Vivo.
abstract: Mastitis is a serious medical condition of dairy cattle. Here, we evaluated whether the degree of virulence of mastitis pathogens in a mouse model can be linked to the inflammatory response that they provoke. Clinical isolates ofStaphylococcus aureus(S. aureus) (strain 556 and 392) andEscherichia coli(E. coli) (676 and 127), and laboratory control strains [8325-4 (S. aureus) and MG1655 (E. coli)], were injected i.p. into mice, followed by the assessment of clinical scores and inflammatory parameters. As judged by clinical scoring,E. coli127 exhibited the largest degree of virulence among the strains. All bacterial strains induced neutrophil recruitment. However, whereasE. coli127 induced high peritoneal levels of CXCL1, G-CSF, and CCL2, strikingly lower levels of these were induced by the less virulent bacterial strains. High concentrations of these compounds were also seen in blood samples taken from animals infected withE. coli127, suggesting systemic inflammation. Moreover, the levels of CXCL1 and G-CSF, both in the peritoneal fluid and in plasma, correlated with clinical score. Together, these findings suggest that highly virulent clinical mastitis isolates produce a distinct cytokine profile that shows a close correlation with the severity of the bacterial infection.
authors.affiliation: Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences , Uppsala , Sweden.
authors.forename: Carl-Fredrik
authors.initials: CF
authors.lastname: Johnzon
authors.affiliation: National Veterinary Institute (SVA) , Uppsala , Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Artursson
authors.affiliation: National Veterinary Institute (SVA) , Uppsala , Sweden.
authors.forename: Robert
authors.initials: R
authors.lastname: Söderlund
authors.affiliation: Department of Biomedical Science and Veterinary Public Health, Swedish University of Agricultural Sciences , Uppsala , Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Guss
authors.affiliation: Department of Medical Biochemistry and Microbiology, BMC, Uppsala University , Uppsala , Sweden.
authors.forename: Elin
authors.initials: E
authors.lastname: Rönnberg
authors.affiliation: Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Medical Biochemistry and Microbiology, BMC, Uppsala University, Uppsala, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Pejler
keywords: bacterial infections; bovine; chemokines; cytokines; inflammation mediators; mastitis