 Klebsiella pneumonii is a gram negative bacterium that can cause a variety of infections in humans. It is particularly dangerous because it can form a protective layer around itself called a biofilm, making it resistant to many antibiotics. Biofilms are composed of extracellular polymeric substances, EPS, produced by the bacteria, which provide protection from environmental stressors such as temperature, pH, and antibiotics. In addition, biofilms have been shown to be more virulent than planktonic cells, leading to increased morbidity and mortality rates. Furthermore, the presence of biofilms on medical implants or other surfaces can lead to device failure and infection. This article was authored by Claudia Vado, Francesca Longo, Maria Pia Balais, and others.