A wound is considered chronic when healing does not occur in the expected time, presents complications and does not respond easily to the treatments used. The main types of chronic wounds are: vascular ulcers, pressure ulcers and diabetic foot ulcers. The impact of an infected wound on healthcare is enormous. Infections of the dermis, including non-healing diabetic foot ulcers affect approximately 2 million people, cause 200,000 deaths, and are responsible for more than $18 billion in direct medical costs in the United States annually. These ulcers are usually colonised by more than one type of bacteria and many of them have the ability to associate and generate biofilms that hinder drug therapy and favour microorganisms.