Cold Atmospheric Plasma for Dermatophytes: In Vitro Efficacy Against T. rubrum and M. canis Original paper
Researched by:
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Karen Pendergrass
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Karen Pendergrass
Read MoreKaren Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease—four years before the first published case study.
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Microsporum canis (M. canis)
Microsporum canis (M. canis)
OverviewMicrosporum canis (M. canis) is a zoophilic dermatophyte common in cats and dogs, responsible for 90% of feline dermatophytoses worldwide.[1][2] It has significant zoonotic potential, transmitting to humans through fomites or direct animal contact, causing severe superficial mycosis. M. canis is considered anthropo-zoophilic and can infect pediatric or immunocompromised patients, causing severe inflammatory responses such […]
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Karen Pendergrass
Read More
Researched by:
-
Karen Pendergrass
ID
Karen Pendergrass
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
What was studied?
This in vitro study investigated the antifungal efficacy of cold atmospheric plasma (CAP), generated via surface microdischarge (SMD) technology using ambient air, against two clinically significant dermatophytes: Trichophyton rubrum and Microsporum canis. CAP emits a mixture of reactive oxygen and nitrogen species (ROS/RNS), UV photons (280–420 nm), and charged particles capable of inducing cellular damage in microorganisms. The researchers compared the antifungal activity of CAP treatments of varying durations (5, 8, 10 minutes) and frequencies (single vs. daily treatments) against standard antifungal interventions: ciclopirox olamine and UVC irradiation (0.120 J/cm²). Growth inhibition of fungal colonies was monitored for up to nine days post-treatment.
Who was studied?
Fungal strains of T. rubrum and M. canis were isolated from untreated patients with tinea pedis and tinea capitis, respectively, at the Department of Dermatology, University Hospital Regensburg. Cultures were prepared using Sabouraud–glucose agar, and CAP treatments were applied using the FlatPlaSter device. All treatments were performed in quadruple across at least five independent experiments to ensure statistical reliability when using cold atmospheric plasma for dermatophytes
Most important findings
Daily 10-minute CAP treatments produced fungal growth inhibition comparable to that of ciclopirox olamine, with both T. rubrum and M. canis colony sizes remaining virtually unchanged over nine days. By contrast, one-time CAP treatments and shorter daily exposures (5 or 8 minutes) produced only partial inhibition. UVC treatment showed only transient suppression of growth, and pre-treatment of agar alone with CAP had no antifungal effect, confirming direct mycelial interaction is required.
Summary of key results (Day 9 colony sizes in mm):
| Treatment | T. rubrum (Day 9) | M. canis (Day 9) |
|---|---|---|
| Untreated Control | 25.6 ± 2.7 | 32.6 ± 1.5 |
| Daily CAP, 10 min | 4.3 ± 0.7 | 5.2 ± 0.6 |
| Ciclopirox Olamine | 4.7 ± 0.4 | 5.9 ± 0.9 |
| Daily CAP, 8 min | 15.5 ± 1.6 | 13.8 ± 10.7 |
| Daily CAP, 5 min | 15.8 ± 3.2 | 13.4 ± 7.6 |
| UVC, one-time | ~temporary inhibition only | ~temporary inhibition only |
The antifungal mechanism is attributed primarily to ROS/RNS interaction with fungal membranes and DNA, rather than UV or heat, as the emitted UV was negligible (25 nW/cm²) and thermal rise remained below 4°C
Key implications
CAP demonstrates strong fungistatic activity and holds promise as a contact-free alternative for treating dermatophytoses, especially where systemic antifungal use is contraindicated due to toxicity, liver involvement, or treatment failure. While complete mycelial eradication was not achieved (as expected in a high-biomass in vitro setup), the suppression was sufficient to suggest clinical potential. Importantly, CAP’s antimicrobial action does not stem from residual effects on growth medium, indicating direct ROS/RNS-mediated cytotoxicity. This positions CAP as a novel adjunct or alternative in antifungal therapy, especially for superficial infections like tinea capitis or tinea pedis. Further animal and clinical studies are warranted to translate these findings into therapeutic protocols.