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Updated: Mar 13, 2026
Author Spotlight: Studying Host-Microbe Interactions in Wound Biofilm Formation
Published on: June 16, 2023
Topical Minocycline Effectively Decontaminates and Reduces Inflammation in Infected Porcine Wounds
Lauren Tracy Daly1,2, David M Tsai1,2, Mansher Singh1,2
1Boston, Mass.
Background:
Wound infection can impair postoperative healing. Topical antibiotics have potential to treat wound infection and inflammation and minimize the adverse effects associated with systemic antibiotics.
Methods:
Full-thickness porcine wounds were infected with Staphylococcus aureus. Using polyurethane wound enclosure devices, wounds were treated with topical 100 μg/ml minocycline, topical 1000 μg/ml minocycline, topical saline control, or 4 mg/kg intravenous minocycline. Bacteria were quantified in wound tissue and fluid obtained over 9 hours. Immunosorbent assays were used to analyze inflammatory marker concentrations. Minocycline's effect on in vitro migration and proliferation of human keratinocytes and fibroblasts was tested using scratch assays and metabolic assays, respectively.
Results:
After 6 hours, 100 and 1000 μg/ml topical minocycline decreased bacteria in wound tissue to 3.5 ± 0.87 and 2.9 ± 2.3 log colony-forming units/g respectively, compared to 8.3 ± 0.9 log colony-forming units/g in control wounds (p < 0.001) and 6.9 ± 0.2 log colony-forming units/g in wounds treated with 4 mg/kg intravenous minocycline (p < 0.01). After 2 hours, topical minocycline reduced concentrations of the inflammatory cytokines interleukin-1β, interleukin-6, and tumor necrosis factor-α (p < 0.01), and inflammatory cell counts in wound tissue (p < 0.05). In noninfected wounds, topical minocycline significantly reduced interleukin-1β, interleukin-6, and inflammatory cell counts after 4 hours (p < 0.01). Matrix metalloproteinase-9 concentrations decreased after 1-hour treatment (p < 0.05). Keratinocyte and fibroblast in vitro functions were not adversely affected by 10 μg/ml minocycline or less.
Conclusions:
Topical minocycline significantly reduces bacterial burden and inflammation in infected wounds compared with wounds treated with intravenous minocycline or control wounds. Minocycline also decreases local inflammation independently of its antimicrobial effect.
Insights
Topical minocycline effectively reduces bacterial load and inflammation in infected wounds. This antibiotic also lessens local inflammation, independent of its antimicrobial action, offering a promising wound healing treatment.
Area of Science:
- Wound healing research
- Dermatology
- Infectious disease management
Background:
- Wound infection impedes postoperative healing.
- Topical antibiotics offer an alternative to systemic antibiotics for treating wound infection and inflammation, potentially minimizing adverse effects.
Purpose of the Study:
- To evaluate the efficacy of topical minocycline in treating Staphylococcus aureus-infected wounds.
- To assess the impact of topical minocycline on wound inflammation and cellular functions.
Main Methods:
- Full-thickness porcine wounds infected with Staphylococcus aureus were treated with topical or intravenous minocycline.
- Bacterial load, inflammatory markers (cytokines, cell counts), and matrix metalloproteinase-9 were quantified.
- In vitro effects of minocycline on keratinocyte and fibroblast migration and proliferation were assessed.
Main Results:
- Topical minocycline significantly reduced bacterial burden in infected wounds compared to controls and intravenous administration.
- Topical minocycline decreased inflammatory cytokines (IL-1β, IL-6, TNF-α) and inflammatory cell counts in infected and non-infected wounds.
- Minocycline demonstrated no adverse effects on keratinocyte and fibroblast functions in vitro at concentrations up to 10 μg/ml.
Conclusions:
- Topical minocycline is effective in reducing bacterial burden and inflammation in infected wounds.
- Minocycline exhibits anti-inflammatory effects independent of its antimicrobial properties.
- Topical minocycline presents a viable therapeutic option for managing infected wounds.
