title: Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle.
abstract: This study evaluated the efficacy of a recombinant lysostaphin fused to a protein transduction domain (rLYS-PTD) as a dry-cow therapy for the treatment of experimentally induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diagonal mammary quarters approximately 45d before dry off. Staphylococcus aureus-infected mammary quarters of cows were randomly assigned to 1 of 2 treatment groups at dry off: (1) 279mg of rLYS-PTD in 50mL of vehicle (n=11 cows; 22 quarters) or (2) 50mL of vehicle solution (n=11 cows; 22 quarters) by intramammary infusion. All cows were followed for 30d postpartum to determine cure rates using bacteriologic culture, somatic cell counts, and clinical mastitis scores. No cures were recorded in either the treatment or control groups. Milk somatic cell count, bacterial colony counts, and mastitis scores did not significantly differ between treatment groups. In conclusion, rLYS-PTD was not an effective dry-cow therapeutic for chronic, subclinical Staph. aureus mastitis at the tested dose and formulation.
authors.affiliation: Department of Veterinary Medicine and Surgery, University of Missouri, Columbia 65211.
authors.forename: K J
authors.initials: KJ
authors.lastname: Hoernig
authors.affiliation: USDA, Beltsville, MD 20705.
authors.forename: D M
authors.initials: DM
authors.lastname: Donovan
authors.affiliation: Department of Veterinary Medicine and Surgery, University of Missouri, Columbia 65211.
authors.forename: P
authors.initials: P
authors.lastname: Pithua
authors.affiliation: Veterinary Medical Diagnostic Laboratory, University of Missouri, Columbia 65211.
authors.forename: F
authors.initials: F
authors.lastname: Williams
authors.affiliation: Department of Veterinary Medicine and Surgery, University of Missouri, Columbia 65211. Electronic address: middletonjr@missouri.edu.
authors.forename: J R
authors.initials: JR
authors.lastname: Middleton
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use*; D002417:Cattle; D005260:Female; D008248:Lysostaphin / Q000627:therapeutic use*; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000382:microbiology; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D008248:Lysostaphin
keywords: Staphylococcus aureus mastitis; dry-cow therapy; lysostaphin