Biofilm

For biographic motion picture, see Biographical film.

Staphylococcus aureus biofilm on an indwelling catheter
Probable cyanobacteria in the vertical section of a silicified biofilm from the Lower Cretaceous. Very shallow hypersaline environment of the Urgonian carbonate platform of Provence, south eastern France.
IUPAC definition

Aggregate of microorganisms in which cells that are frequently embedded within a self-produced matrix of extracellular polymeric substances (EPSs) adhere to each other and/or to a surface.

  • A biofilm is a system that can be adapted internally to environmental conditions by its inhabitants.
  • The self-produced matrix of extracellular polymeric substances, which is also referred to as slime, is a polymeric conglomeration generally composed of extracellular biopolymers in various structural forms.[1]

A biofilm is a syntrophic community of microorganisms in which cells stick to each other and often also to a surface.[2][3] These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs).[2][3] The cells within the biofilm produce the EPS components, which are typically a polymeric combination of extracellular polysaccharides, proteins, lipids and DNA.[2][3][4] Because they have a three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes".[5][6]

Biofilms may form on living (biotic) or non-living (abiotic) surfaces and can be common in natural, industrial, and hospital settings.[3][7] They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium.[8] Biofilms can form on the teeth of most animals as dental plaque, where they may cause tooth decay and gum disease.

Microbes form a biofilm in response to a number of different factors,[9] which may include cellular recognition of specific or non-specific attachment sites on a surface, nutritional cues, or in some cases, by exposure of planktonic cells to sub-inhibitory concentrations of antibiotics.[10][11] A cell that switches to the biofilm mode of growth undergoes a phenotypic shift in behavior in which large suites of genes are differentially regulated.[12]

A biofilm may also be considered a hydrogel, which is a complex polymer that contains many times its dry weight in water. Biofilms are not just bacterial slime layers but biological systems; the bacteria organize themselves into a coordinated functional community. Biofilms can attach to a surface such as a tooth or rock, and may include a single species or a diverse group of microorganisms. Subpopulations of cells within the biofilm differentiate to perform various activities for motility, matrix production, and sporulation, supporting the overall success of the biofilm.[13] The biofilm bacteria can share nutrients and are sheltered from harmful factors in the environment, such as desiccation, antibiotics, and a host body's immune system. A biofilm usually begins to form when a free-swimming, planktonic bacterium attaches to a surface.[14][page needed]

  1. ^ Vert M, Doi Y, Hellwich KH, Hess M, Hodge P, Kubisa P, et al. (2012). "Terminology for biorelated polymers and applications (IUPAC Recommendations 2012)". Pure and Applied Chemistry. 84 (2): 377–410. doi:10.1351/PAC-REC-10-12-04.
  2. ^ a b c López D, Vlamakis H, Kolter R (July 2010). "Biofilms". Cold Spring Harbor Perspectives in Biology. 2 (7): a000398. doi:10.1101/cshperspect.a000398. PMC 2890205. PMID 20519345.
  3. ^ a b c d Hall-Stoodley L, Costerton JW, Stoodley P (February 2004). "Bacterial biofilms: from the natural environment to infectious diseases". Nature Reviews. Microbiology. 2 (2): 95–108. doi:10.1038/nrmicro821. PMID 15040259. S2CID 9107205.
  4. ^ Aggarwal S, Stewart PS, Hozalski RM (January 2016). "Biofilm Cohesive Strength as a Basis for Biofilm Recalcitrance: Are Bacterial Biofilms Overdesigned?". Microbiology Insights. 8 (Suppl 2): 29–32. doi:10.4137/MBI.S31444. PMC 4718087. PMID 26819559.
  5. ^ Watnick P, Kolter R (May 2000). "Biofilm, city of microbes". Journal of Bacteriology. 182 (10): 2675–9. doi:10.1128/jb.182.10.2675-2679.2000. PMC 101960. PMID 10781532.
  6. ^ "Building Codes for Bacterial Cities | Quanta Magazine". Quanta Magazine. Archived from the original on 26 July 2017. Retrieved 25 July 2017.
  7. ^ Lear G, Lewis GD, eds. (2012). Microbial Biofilms: Current Research and Applications. Caister Academic Press. ISBN 978-1-904455-96-7.
  8. ^ O'Toole GA, Kolter R (May 1998). "Initiation of biofilm formation in Pseudomonas fluorescens WCS365 proceeds via multiple, convergent signalling pathways: a genetic analysis". Molecular Microbiology. 28 (3): 449–61. doi:10.1046/j.1365-2958.1998.00797.x. PMID 9632250. S2CID 43897816.
  9. ^ O'Toole GA, Kolter R (October 1998). "Flagellar and twitching motility are necessary for Pseudomonas aeruginosa biofilm development". Molecular Microbiology. 30 (2): 295–304. doi:10.1046/j.1365-2958.1998.01062.x. PMID 9791175. S2CID 25140899.
  10. ^ Karatan E, Watnick P (June 2009). "Signals, regulatory networks, and materials that build and break bacterial biofilms". Microbiology and Molecular Biology Reviews. 73 (2): 310–47. doi:10.1128/MMBR.00041-08. PMC 2698413. PMID 19487730.
  11. ^ Hoffman LR, D'Argenio DA, MacCoss MJ, Zhang Z, Jones RA, Miller SI (August 2005). "Aminoglycoside antibiotics induce bacterial biofilm formation". Nature. 436 (7054): 1171–5. Bibcode:2005Natur.436.1171H. doi:10.1038/nature03912. PMID 16121184. S2CID 4404961. (primary source)
  12. ^ An D, Parsek MR (June 2007). "The promise and peril of transcriptional profiling in biofilm communities". Current Opinion in Microbiology. 10 (3): 292–6. doi:10.1016/j.mib.2007.05.011. PMID 17573234.
  13. ^ Momeni B (June 2018). "Division of Labor: How Microbes Split Their Responsibility". Current Biology. 28 (12): R697–R699. Bibcode:2018CBio...28.R697M. doi:10.1016/j.cub.2018.05.024. PMID 29920261. S2CID 49315067.
  14. ^ Case C, Funke B, Tortora G. Microbiology An Introduction (tenth ed.).