title: Intracellular killing of mastitis pathogens by penethamate hydriodide following internalization into mammary epithelial cells.
abstract: Penethamate hydriodide was highly effective in killing Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae and Staphylococcus aureus that internalized mammary epithelial cells. At higher concentrations (32 microg/mL to 32 mg/mL), killing rates ranged from 85% to 100%. At lower concentrations (0.032 microg/mL to 3.2 microg/mL), killing rates ranged from 0 to 80%. Results of this proof-of-concept study demonstrated that: (1) penethamate hydriodide is capable of entering mammary epithelial cells and killing intracellular mastitis pathogens without affecting mammary epithelial cell viability, (2) the in vitro model used is capable of quantifying the fate of mastitis pathogens internalized into mammary epithelial cells, and (3) this in vitro model can be used to determine the effectiveness of antibiotics at killing bacteria within the cytoplasm of mammary epithelial cells.
authors.affiliation: Department of Animal Science & Food Safety Center of Excellence, The University of Tennessee, Knoxville, TN 37996, USA. ralmeida@utk.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Almeida
authors.forename: D
authors.initials: D
authors.lastname: Patel
authors.forename: G M
authors.initials: GM
authors.lastname: Friton
authors.forename: S P
authors.initials: SP
authors.lastname: Oliver
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D002417:Cattle; D018920:Coculture Techniques / Q000662:veterinary; D004847:Epithelial Cells / Q000382:microbiology / Q000502:physiology*; D005260:Female; D008321:Mammary Glands, Animal / Q000166:cytology / Q000382:microbiology*; D008414:Mastitis, Bovine / Q000188:drug therapy / Q000382:microbiology* / Q000473:pathology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D010400:Penicillin G / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D013291:Streptococcus / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; C008780:penethamate hydroiodide; D010400:Penicillin G