title: Effect of intramammary injection of rboGM-CSF on milk levels of chemiluminescence activity, somatic cell count, and Staphylococcus aureus count in Holstein cows with S. aureus subclinical mastitis.
abstract: The effect of intramammary injection of recombinant bovine granulocyte-macrophage colony-stimulating factor (rboGM-CSF, 400 microg/10 mL) on quarter milk levels of chemiluminescence (CL) activity, and somatic cell count (SCC) and shedding pattern of Staphylococcus aureus was investigated. Ten Holstein cows, naturally infected with S. aureus were used, with either early-stage or late-stage subclinical mastitis. Injection of rboGM-CSF caused a remarkable increase in milk CL activity with a peak at 6 h after the cytokine injection in the early- and late-stage groups. In the early-stage group, milk SCC stayed around preinjection level at 6 h, rose significantly on days 1 and 2, and was followed by a smooth and significant decline to an under preinjection level (below 200 000 cells/mL) on day 7 postinjection. Alternatively, in the late-stage group, milk SCC rose significantly at 6 h after the cytokine injection and maintained high levels thereafter. The milk S. aureus count decreased drastically by the cytokine injection in the early-stage group. The bacterial count was moderately decreased in the late-stage group, but increased back to preinoculation levels on day 7 after the cytokine injection. The results suggest that the rboGM-CSF has a potential as a therapeutic agent for S. aureus infection causing subclinical mastitis of dairy cows, if the cytokine is applied at the initial stage of infection.
authors.affiliation: Department of Production Animal Diseases, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan. htaka@affrc.go.jp
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Masaharu
authors.initials: M
authors.lastname: Odai
authors.forename: Kenji
authors.initials: K
authors.lastname: Mitani
authors.forename: Shigeki
authors.initials: S
authors.lastname: Inumaru
authors.forename: Shozo
authors.initials: S
authors.lastname: Arai
authors.forename: Rieko
authors.initials: R
authors.lastname: Horino
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Yokomizo
mesh_terms: D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D015169:Colony Count, Microbial / Q000662:veterinary; D003612:Dairying; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage / Q000627:therapeutic use*; D007267:Injections / Q000662:veterinary; D008163:Luminescent Measurements; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology; D008892:Milk / Q000166:cytology*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000502:physiology*; D016896:Treatment Outcome
chemical_list: D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor