Cold Plasma Therapy shows promise for tackling resistant equine wound infections

   Cuts, lacerations and puncture wounds are an unfortunate fact of life for horses. While many wounds heal quickly after prompt veterinary treatment, others, particularly those involving the lower limbs, can become prolonged and frustrating cases. Constant movement, contamination and infection can all interfere with healing, while the development of exuberant granulation tissue, or "proud flesh", may further delay recovery. 

Standard treatment relies on thorough wound debridement to remove dead and infected tissue, together with copious irrigation to reduce bacterial contamination. Current veterinary recommendations suggest antibiotics should not automatically be the first line of treatment for every infected wound, particularly given the growing global concern over antimicrobial resistance. However, infections caused by multidrug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) present an increasingly difficult therapeutic challenge.

Researchers in Germany have now investigated an innovative technology that could offer a valuable alternative. Led by Sandra Kurras of Tierklinik Luesche GmbH, the team evaluated the use of Cold Atmospheric Plasma-Aerosol (CAP-A)* as a non-antibiotic treatment for infected equine wounds containing antibiotic-resistant bacteria.

Although the name sounds highly technical, the principle is relatively straightforward. The CAP-A system uses a high-voltage electrical field to energise ordinary air, producing highly reactive oxygen molecules known as Reactive Oxygen Species (ROS). These include compounds such as hydroxyl radicals together with very small amounts of ozone.

An ultrasonic nebuliser then combines these reactive molecules with a fine water mist, creating electrostatically active droplets that are directed onto the wound from a distance of around 5–10 cm. A single three-minute treatment can cover an area of up to 20 × 20 cm.

The reactive oxygen species damage bacterial cell membranes, proteins and DNA, making it difficult for bacteria to survive or develop resistance. At the same time, the fine mist keeps the wound moist, helping regulate wound pH and preventing the tissues from drying out – both factors known to support normal healing.

The retrospective case series included four horses ranging in age from just five weeks to 11 years. Each horse had a deep infected wound or sinus infection containing multidrug-resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA).

The horses received CAP-A treatment once daily for between 20 and 55 days. Each session consisted of two three-minute applications, while identical wound dressings were used throughout the study. Bacterial cultures and antibiotic sensitivity testing were performed before and after treatment, and wound healing was monitored photographically.

The results were encouraging. All four horses showed substantial reductions in bacterial contamination, with MRSA becoming undetectable after just 10 days of treatment. Clinical healing progressed in every case despite the absence of antibiotic therapy, and no adverse effects or signs of discomfort were observed during treatment sessions. The researchers also reported improvements in wounds infected with multidrug-resistant Gram-negative bacteria.

Although the study involved only four horses and lacked a control group, the findings suggest that CAP-A could become a valuable addition to equine wound care, particularly when antimicrobial resistance limits conventional treatment options. By reducing bacterial burden without relying on antibiotics, the technology also aligns with the wider One Health initiative, which seeks to reduce unnecessary antimicrobial use across both human and veterinary medicine.

Larger prospective clinical trials will now be needed to confirm the effectiveness of CAP-A, establish treatment protocols and determine where it best fits alongside established wound management techniques. Nevertheless, these initial results indicate that cold atmospheric plasma-aerosol could represent an important new tool in the battle against antibiotic-resistant wound infections in horses.

For more details, see:

Kurras, Sandra, Theresa Maria Conze, Sinje Obermann, Robert Fuchs, Tim Tischendorf, Derek C. Knottenbelt, and Marc Koene. 2026.

Cold Atmospheric Plasma-Aerosol Treatment of Equine Antibiotic-Resistant Wound Infection: A Preliminary Case Series

 Animals (2026) 16, no. 15: 2380.

https://doi.org/10.3390/ani16152380

* PLASMO®VET CAP-A (WK-MedTec GmbH, Bückeburg, Germany)