We investigated the effect of ramoplanin coating on Staphylococcus aureus colonization of catheter segments in mice. Segments (1 cm in length) were inserted subcutaneously, 10(7) cfu of S. aureus were inoculated nearby at different times and segments were removed 24 or 48 h later. Uncoated segments were colonized with 10(4) to >10(5) cfu, whereas ramoplanin-coated segments had mean counts of <10 to approximately 100 cfu. Ramoplanin coating may prevent colonization of catheters during the first few days after insertion.