Q. Consider the following statements:

  1. Biofilms can form on medical implants within human tissues.
  2. Biofilms can form on food and food processing surfaces.
  3. Biofilms can exhibit antibiotic resistance.

Which of the statements given above are correct?

  • 1 and 2 only
  • 2 and 3 only
  • 1 and 3 only
  • 1, 2 and 3

Answer: (d) 1, 2 and 3

Biofilms
  • Biofilms are a collective of one or more types of microorganisms that can grow on many different surfaces. Microorganisms that form biofilms include bacteria, fungi and protists.
  • A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface.
    • These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA.
    • Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as “cities for microbes”.
  • Biofilms are ubiquitous and they form on virtually all surfaces immersed in natural aqueous environment, e.g., water pipes, living tissue, tooth surface, implanted medical devices, dental implants, etc.
  • Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. Thus biofilm can form on food and food processing surfaces. For example escherichia coli,  Salmonella enterica etc.  Salmonella enterica contaminates a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly.
  • Bacterial biofilms show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis and other components of the body’s defence system. Thus they cause chronic infections.
  • Habitats:
    • Biofilms can grow in the most extreme environments: from, for example, the extremely hot, briny waters of hot springs ranging from very acidic to very alkaline, to frozen glaciers.
    • Biofilms can be found on rocks and pebbles at the bottoms of most streams or rivers and often form on the surfaces of stagnant pools of water.
      • Biofilms are important components of food chains in rivers and streams and are grazed by the aquatic invertebrates upon which many fish feed. Biofilms are found on the surface of and inside plants.
Five stages of biofilm development