Abstract: Objective: To explore the effect of dupilumab on Staphylococcus aureus colonization in adult moderate to severe atopic dermatitis and its mechanism. Methods: Patients with moderate to severe atopic dermatitis from July 2022 to August 2023 were enrolled into the experimental group, and healthy subjects were selected as the controls. The patients in the experimental group were treated with duprizumab. Before treatment and at 8 week after treatment, the colonization of Staphylococcus aureus at the skin lesions, as well as the levels of serum IL-4, IL-13, IL-19, IL-33, and total IgE, were measured in both groups. Results: The colonization rate of Staphylococcus aureus was 100% in the experimental group (30 cases) before treatment and 3.33% in the healthy group (30 cases) (P<0.05). After 8 weeks of treatment, the colonization amount of Staphylococcus aureus in the experimental group (3394±1837 CFU/cm2) was significantly lower than that before treatment (108741±56758 CFU/cm2), with statistical significance. The levels of serum IL-4, IL-13, IL-19, IL-33 and total IgE after treatment were significantly lower than those before treatment, with statistically significant differences (P<0.05). Conclusion: Dupilumab can rapidly reduce the colonization of Staphylococcus aureus in skin lesions of patients with atopic dermatitis, which may be related to the reduction of type 2 inflammatory factors and the severity of atopic dermatitis.

Key words: atopic dermatitis, duprizumab, Staphylococcus aureus, interleukin, type 2 inflammation