Related Experiment Video
Updated: Jul 16, 2026
Isolation and Culture of Primary Human Mammary Epithelial Cells
Published on: May 3, 2024
Intracellular killing of mastitis pathogens by penethamate hydriodide following internalization into mammary
R A Almeida1, D Patel, G M Friton
1Department of Animal Science & Food Safety Center of Excellence, The University of Tennessee, Knoxville, TN 37996, USA. ralmeida@utk.edu
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.
Insights
Penethamate hydriodide effectively kills intracellular mastitis pathogens like Streptococcus and Staphylococcus within mammary cells. This study validates an in vitro model for testing antibiotic efficacy against intracellular bacteria.
Area of Science:
- Veterinary Microbiology
- Cell Biology
- Pharmacology
Background:
- Mastitis pathogens frequently internalize mammary epithelial cells, evading conventional antibiotic treatments.
- Intracellular bacterial infections pose a significant challenge in bovine mastitis management.
- Understanding antibiotic penetration and efficacy within host cells is crucial for developing new therapeutic strategies.
Purpose of the Study:
- To evaluate the efficacy of penethamate hydriodide against intracellular mastitis pathogens.
- To determine if penethamate hydriodide can penetrate mammary epithelial cells and kill internalized bacteria.
- To validate an in vitro model for assessing antibiotic activity against intracellular bacteria in mammary cells.
Main Methods:
- An in vitro model using mammary epithelial cells was established.
- Bacterial strains including Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae, and Staphylococcus aureus were internalized into cells.
- The killing rates of penethamate hydriodide at various concentrations were determined by quantifying surviving bacteria.
- Mammary epithelial cell viability was assessed to ensure drug safety.
Main Results:
- Penethamate hydriodide demonstrated high killing rates (85-100%) against internalized Streptococcus and Staphylococcus species at concentrations of 32 microg/mL to 32 mg/mL.
- Lower concentrations (0.032 microg/mL to 3.2 microg/mL) showed variable killing rates (0-80%).
- The antibiotic effectively killed intracellular bacteria without compromising mammary epithelial cell viability.
- The in vitro model accurately quantified the fate of internalized pathogens.
Conclusions:
- Penethamate hydriodide possesses the capability to enter mammary epithelial cells and eliminate intracellular mastitis pathogens.
- The developed in vitro model serves as a reliable tool for quantifying intracellular bacterial survival and assessing antibiotic effectiveness.
- This model can be utilized for screening and validating novel antibiotics targeting intracellular mastitis bacteria.
Related Concept Videos
01:25Clinical Significance of Antibiotic Resistance
01:23Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...