RESEARCH ON THE MEDICAL EFFICACY of topical antimicrobials and antibiotics against infections has focused largely on the effect on free-floating, planktonic bacteria. IN THE PRESENCE OF nonbiological surfaces (eg, catheters, prosthetic devices, biomaterials), however, bacteria form highly complex biofilm systems that resist traditional medical treatment. BACTERIAL PATHOGENS commonly found in chronic infections in both the planktonic and biofilm state were challenged with a variety of commonly used topical antimicrobial formulations. BIOFILM BACTERIA were shown to be more resistant to killing than planktonic bacteria. Antimicrobial skin preparation times were adequate to significantly reduce bacterial populations protected in biofilms.