The Propionibacterium acnes biofilm has previously been shown to exist via genomic studies and to make a biological glue which allows for adherence to follicular walls. This gylcocalyx polymer secreted by P acnes also finds its way into sebum composition where it causes the adhesiveness of keratinocytes leading to comedones. An appreciation of P acnes biofilms and secretions has implications in immunogenicity of the organism, clinical course of acne, and therapy for comedonal and inflammatory acne.