Abstract: Objective: To evaluate the efficacy of cold atmospheric plasma (CAP) in a guinea pig skin model of fungal-bacterial co-infection. Methods: 35 immunocompromised guinea pigs were used to establish a co-infection model with Trichophyton rubrum and Staphylococcus aureus. They were randomly divided into 5 groups, 7 in each group. Group A (blank group), group B (positive control group, treated with bifonazole cream and mupirocin ointment), group C (low dose CAP group, 30% intensity of 3 gear), group D (medium dose CAP group, 50% intensity of 5 gear), group E (high dose CAP group, 80% intensity of 8 gear). The efficacy was assessed through clinical, microbiological, and pathological examinations. Results: The differences in skin lesion scores before and after treatment were statistically significant (P＜0.05) in 4 groups (groups B-E). After 2 weeks of treatment, group A (11.43 ± 0.98), group B (1.71 ± 0.49), group C (4.86 ± 1.07), group D (3.43 ± 0.54), and group E (1.86 ± 1.07). Groups B, C, D, and E were better than group A (P＜0.001), and there was no significant difference between group B, D and E. The negative rates of fungal microscopy and microbiological cultures in groups B-E were higher than before treatment (P＜0.05), with no significant difference among groups. There were no significant difference in pathological scores between group B and D, E. Conclusion: The efficacy of CAP in this model is comparable to the combined effects of mupirocin and bifonazole, increasing with dosage within a specific range and stabilizing after reaching a certain dosage.

Key words: cold atmospheric plasma, superficial mycoses, bacterial colonization, guinea pig