A thin, slimy film of bacteria that adheres to a surface. A thin, gelatinous-like film secreted by bacterial cells providing them protection from many disinfectants, antibiotics and desiccation. Biofilms form in the bronchioles and alveolar sacs, commonly seen in cystic fibrosis patients who become infected by Pseudomonas aeruginosa. Also forms on catheters such as ET tubes, urinary catheters, blood stream catheters and on the surfaces of implanted devices.