Microbiology Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

A biofilm is best defined as a structured community of microorganisms that adhere to surfaces. This definition highlights the complexity and organization of biofilms, which can consist of multiple species of bacteria, fungi, algae, and even protozoa, all embedded in a self-produced matrix of extracellular polymeric substances (EPS). This matrix not only helps the microorganisms stick to each other and to surfaces but also protects them from environmental stresses, including antibiotics and the immune system.

Biofilms are commonly found in natural environments, such as rivers, streams, and oceans, as well as in man-made systems, such as pipes, medical devices, and tooth surfaces. The organized structure of a biofilm allows for increased communication among microorganisms and can lead to enhanced metabolic capabilities.

Understanding biofilms is essential in both ecological and medical contexts, as they are often associated with chronic infections and contribute to the persistence of bacteria in various environments.