The invention concerns the use of an antimicrobial composition comprising metallic silver and metallic ruthenium as well as at least one vitamin or at least one vitamin derivative for the topical treatment or prevention of skin, skin adnexa or mucosa diseases which are caused by infection with at least one microorganism. The invention also concerns a bandaging material or patch comprising an antimicrobial composition which comprises metallic silver and metallic ruthenium as well as at least one vitamin or at least one vitamin derivative. The antimicrobial composition (“AgXX”) has a broad-spectrum effect against bacteria (a: E. coli) and fungi (b: Pathogen is yeast and c: Penicillium).a) Escherichia coli (additionally silver (“Ag”) as control),b) Candida parapsilosis,c) Penicillium notatum;