Biofilms
What is a biofilm?
Biofilms are formations that occur when a group of microorganisms such as bacteria, fungi, parasites and viruses attach themselves to a surface and create a colony.1 The biofilm forms itself into a type of ‘shield’ that has a glue-like consistency, often referred to as ‘slime’.1 These biofilms act as a barrier and help the colony to defend itself against antimicrobial treatments and our immune cells.2
Biofilms can be part of the reason that some wounds may be difficult to heal, and persistent infections keep recurring.1 However, biofilms aren’t always undesirable, and can also house healthy bacteria in our digestive system and on our skin.3
Where are biofilms found?
A biofilm colony secretes materials that provide a structured matrix, similar to cement, that adheres to surfaces such as the lining of the gastrointestinal tract (GIT), urinary tract, respiratory system, heart, mouth (including the teeth), sex organs, eyes, the middle ear and skin.1 Biofilms can also form on medical materials such as catheters, joint replacements, heart valves and they commonly occur in hospitals.1
Common biofilms
A good example of a commonly understood biofilm is the accumulation of plaque (or biofilm) on the teeth. Treating and breaking down plaque can sometimes be challenging; the infection ‘hides’ in the plaque well away from antiseptic treatments and the immune system, sometimes causing gingivitis (inflammation of the gums).1
Another commonly known biofilm is sinusitis (sinus infection). The European Archives of Oto-Rhino-Laryngology published an observational study that showed that 59% of people suffering with a sinus infection had a sinus bacterial biofilm.4 Ear infections, often found in children, have been found to be associated with the presence of middle ear biofilms.1
Biofilms are good at ‘hiding’ microbes
Up to 80% of infections in the body affecting the body systems mentioned above are associated with biofilm formation.5 These biofilms can make it challenging for antimicrobial treatments to penetrate the biofilm.5 A microbial biofilm is continuously changing, stimulating inflammation, and acting as an obstacle for the action of the immune system.1 These types of persistent infections may be correlated to a range of health complaints including middle ear infections, urinary tract infections (UTIs), GIT infections, fungal overgrowth and more.1,6
Biofilm communication
The life cycle of the biofilm includes the microbes communicating via a process called ‘quorum sensing’; where the microbes send messages to each other to start the formation of the matrix (cement) of the biofilm.7 The microbes then communicate with each other as to their total number, and when they distinguish that there is a large colony, they start working as a community.7 Once the biofilm has been formed, channels are developed to allow nutrients in to enhance the development of the colony.7
Date: 2017-08-10
Author: Claire Georgiou
References
Bjarnsholt T. The role of bacterial biofilms in chronic infections. APMIS Suppl. 2013(136):1-51.
Berlanga M, Guerrero R. Living together in biofilms: the microbial cell factory and its biotechnological implications. Microbial Cell Factories 2016;15:165.
Gutierrez S, Moran A, Martinez-Blanco H, et al. The usefulness of non-toxic plant metabolites in the control of bacterial proliferation. Probiotics Antimicrob Proteins 2017. doi: 10.1007/s12602-017-9259-9.
Li H, Wang D, Sun X, et al. Relationship between bacterial biofilm and clinical features of patients with chronic rhinosinusitis. Eur Arch Otorhinolaryngol 2012;269(1):155-163.
Algburi A, Comito N, Kashtanov D, et al. Control of biofilm formation: antibiotics and beyond. Appl Environ Microbiol 2017;83(6):e00165-17.
Donelli G (Ed). Biofilm-based healthcare-associated infections, volume 1. Cham: Springer International Publishing: Imprint: Springer, 2015.
Singh R, Paul D, Jain RK. Biofilms: implications in bioremediation. Trends in Microbiol 2006;14(9):389-397.