Editing Biofilm (section)

== Uses and impact ==
=== In medicine ===
It is suggested that around two-thirds of bacterial infections in humans involve biofilms.<ref name="Del Pozo"/><ref name="Lazar">{{cite journal | vauthors = Lazar V | title = Quorum sensing in biofilms—how to destroy the bacterial citadels or their cohesion/power? | journal = Anaerobe | volume = 17 | issue = 6 | pages = 280–5 | date = December 2011 | pmid = 21497662 | doi = 10.1016/j.anaerobe.2011.03.023 }}</ref> Infections associated with the biofilm growth usually are challenging to eradicate.<ref>{{cite book|title=Biofilm infections|date=2011|publisher=Springer| vauthors = Bjarnsholt T, Jensen PØ, Moser C, Høiby N |isbn=978-1-4419-6083-2|location=New York|oclc=682907381}}</ref> This is mostly due to the fact that mature biofilms display [[antimicrobial tolerance]], and immune response evasions.<ref name="medical biofilms" /><ref name="JMB"/> Biofilms often form on the inert surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices.<ref>{{cite journal | vauthors = Auler ME, Morreira D, Rodrigues FF, Abr Ao MS, Margarido PF, Matsumoto FE, Silva EG, Silva BC, Schneider RP, Paula CR | title = Biofilm formation on intrauterine devices in patients with recurrent vulvovaginal candidiasis | journal = Medical Mycology | volume = 48 | issue = 1 | pages = 211–6 | date = February 2010 | pmid = 20055746 | doi = 10.3109/13693780902856626 | doi-access = free }}</ref> Some of the most difficult infections to treat are those associated with the use of medical devices.<ref name="Del Pozo"/><ref name="niamhcurran"/>

The rapidly expanding worldwide industry for biomedical devices and tissue engineering related products is already at $180&nbsp;billion per year, yet this industry continues to suffer from microbial colonization. No matter the sophistication, microbial infections can develop on all medical devices and tissue engineering constructs.<ref name="medical biofilms">{{cite journal | vauthors = Bryers JD | title = Medical biofilms | journal = Biotechnology and Bioengineering | volume = 100 | issue = 1 | pages = 1–18 | date = May 2008 | pmid = 18366134 | pmc = 2706312 | doi = 10.1002/bit.21838 }}</ref> 60-70% of [[hospital-acquired infection]]s are associated with the implantation of a biomedical device.<ref name="medical biofilms" /> This leads to 2 million cases annually in the U.S., costing the healthcare system over $5&nbsp;billion in additional healthcare expenses.<ref name="medical biofilms" />

The level of antibiotic resistance in a biofilm is much greater than that of non-biofilm bacteria, and can be as much as 5,000 times greater.<ref name="Del Pozo">{{cite journal | vauthors = Del Pozo JL, Rouse MS, Patel R | title = Bioelectric effect and bacterial biofilms. A systematic review | journal = The International Journal of Artificial Organs | volume = 31 | issue = 9 | pages = 786–795 | date = September 2008 | pmid = 18924090 | pmc = 3910516 | doi = 10.1177/039139880803100906 }}</ref> The extracellular matrix of biofilm is considered one of the leading factors that can reduce the penetration of antibiotics into a biofilm structure and contributes to antibiotic resistance.<ref>{{cite journal | vauthors = Vuotto C, Longo F, Balice MP, Donelli G, Varaldo PE | title = Antibiotic Resistance Related to Biofilm Formation in Klebsiella pneumoniae | journal = Pathogens | volume = 3 | issue = 3 | pages = 743–758 | date = September 2014 | pmid = 25438022 | pmc = 4243439 | doi = 10.3390/pathogens3030743 | doi-access = free }}</ref> Further, it has been demonstrated that the evolution of resistance to antibiotics may be affected by the biofilm lifestyle.<ref>{{cite journal | vauthors = Santos-Lopez A, Marshall CW, Scribner MR, Snyder DJ, Cooper VS | title = Evolutionary pathways to antibiotic resistance are dependent upon environmental structure and bacterial lifestyle | journal = eLife | volume = 8 | pages = e47612 | date = September 2019 | pmid = 31516122 | pmc = 6814407 | doi = 10.7554/eLife.47612 | doi-access = free }}</ref> [[Bacteriophage]] therapy can disperse the biofilm generated by antibiotic-resistant bacteria.<ref name="pmid38188636">{{cite journal |vauthors=Pai L, Patil S, Liu S, Wen F |title=A growing battlefield in the war against biofilm-induced antimicrobial resistance: insights from reviews on antibiotic resistance |journal=Front Cell Infect Microbiol |volume=13 |issue= |pages=1327069 |date=2023 |pmid=38188636 |pmc=10770264 |doi=10.3389/fcimb.2023.1327069 |doi-access=free |url=}}</ref>

It has been shown that the introduction of a small current of electricity to the liquid surrounding a biofilm, together with small amounts of antibiotic can reduce the level of antibiotic resistance to levels of non-biofilm bacteria. This is termed the '''bioelectric effect'''.<ref name="Del Pozo"/><ref name="Kim">{{cite journal | vauthors = Kim YW, Subramanian S, Gerasopoulos K, Ben-Yoav H, Wu HC, Quan D, Carter K, Meyer MT, Bentley WE, Ghodssi R | title = Effect of electrical energy on the efficacy of biofilm treatment using the bioelectric effect | journal = npj Biofilms and Microbiomes | volume = 1 | pages = 15016 | date = 2015 | pmid = 28721233 | pmc = 5515217 | doi = 10.1038/npjbiofilms.2015.16 }}</ref> The application of a small [[DC current]] on its own can cause a biofilm to detach from its surface.<ref name="Del Pozo"/> A study showed that the type of current used made no difference to the bioelectric effect.<ref name="Kim"/>

=== In industry ===
{{See also|Biofilms in industry}}
Biofilms can also be harnessed for constructive purposes. For example, many [[sewage treatment]] plants include a [[secondary treatment]] stage in which waste water passes over biofilms grown on filters, which extract and digest organic compounds. In such biofilms, bacteria are mainly responsible for removal of organic matter ([[Biochemical oxygen demand|BOD]]), while [[protozoa]] and [[rotifer]]s are mainly responsible for removal of suspended solids (SS), including pathogens and other microorganisms. [[Slow sand filter]]s rely on biofilm development in the same way to filter surface water from lake, spring or river sources for drinking purposes. What is regarded as clean water is effectively a waste material to these microcellular organisms. Biofilms can help eliminate petroleum oil from contaminated oceans or marine systems. The oil is eliminated by the [[microbial biodegradation|hydrocarbon-degrading]] activities of communities of [[hydrocarbonoclastic bacteria]] (HCB).<ref name="chapter9">{{cite book |title=Microbial Biodegradation: Genomics and Molecular Biology |vauthors=Martins dos Santos VA, Yakimov MM, Timmis KN, Golyshin PN |publisher=Horizon Scientific Press |year=2008 |isbn=978-1-904455-17-2 |pages=[https://archive.org/details/microbialbiodegr0000unse/page/1971 1971] |chapter=Genomic Insights into Oil Biodegradation in Marine Systems |chapter-url=https://books.google.com/books?id=wx6v3TIkzXUC&pg=PA1971 | veditors = Díaz E |url=https://archive.org/details/microbialbiodegr0000unse/page/1971}}</ref>
Biofilms are used in [[microbial fuel cells]] (MFCs) to generate electricity from a variety of starting materials, including complex organic waste and renewable biomass.<ref name="LearGLewisGD" /><ref>{{cite journal |vauthors = Wang VB, Chua SL, Cai Z, Sivakumar K, Zhang Q, Kjelleberg S, Cao B, Loo SC, Yang L |title = A stable synergistic microbial consortium for simultaneous azo dye removal and bioelectricity generation |journal = Bioresource Technology |volume = 155 |pages = 71–76 |date = March 2014 |pmid = 24434696 |doi = 10.1016/j.biortech.2013.12.078 |bibcode = 2014BiTec.155...71W }}</ref><ref>{{cite journal |vauthors = Wang VB, Chua SL, Cao B, Seviour T, Nesatyy VJ, Marsili E, Kjelleberg S, Givskov M, Tolker-Nielsen T, Song H, Loo JS, Yang L |title = Engineering PQS biosynthesis pathway for enhancement of bioelectricity production in pseudomonas aeruginosa microbial fuel cells |journal = PLOS ONE |volume = 8 |issue = 5 |pages = e63129 |year = 2013 |pmid = 23700414 |pmc = 3659106 |doi = 10.1371/journal.pone.0063129 |doi-access = free |bibcode = 2013PLoSO...863129W }}</ref>
Biofilms are also relevant for the improvement of metal dissolution in [[bioleaching]] industry,<ref name="pmid23720034">{{cite journal |vauthors = Vera M, Schippers A, Sand W |title = Progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation—part A |journal = Appl. Microbiol. Biotechnol. |volume = 97 |issue = 17 |pages = 7529–41 |date = September 2013 |pmid = 23720034 |doi = 10.1007/s00253-013-4954-2 |s2cid = 17677624 }}</ref> and aggregation of microplastics pollutants for convenient removal from the environment.<ref>{{Cite journal | vauthors = Chan SY, Wong MW, Kwan BT, Fang JK, Chua SL |date=2022-10-12 |title=Microbial–Enzymatic Combinatorial Approach to Capture and Release Microplastics |journal=Environmental Science & Technology Letters |volume=9 |issue=11 |language=en |pages=975–982 |doi=10.1021/acs.estlett.2c00558 |bibcode=2022EnSTL...9..975C |s2cid=252892619 |issn=2328-8930}}</ref><ref>{{Cite journal | vauthors = Liu SY, Leung MM, Fang JK, Chua SL |date=2021-01-15 |title=Engineering a microbial 'trap and release' mechanism for microplastics removal |journal=Chemical Engineering Journal |language=en |volume=404 |pages=127079 |doi=10.1016/j.cej.2020.127079 |bibcode=2021ChEnJ.40427079L |hdl=10397/88307 |s2cid=224972583 |issn=1385-8947|hdl-access=free }}</ref>

=== Food industry ===
Biofilms have become problematic in several food industries due to the ability to form on plants and during industrial processes.<ref name=ref1>{{cite journal | title = Biofilm formation in food industries: A food safety concern |journal=Food Control|volume=31|issue=2|date=June 2013| vauthors = Srey S, Jahid ID, Ha SD |pages =572–585|issn= 0956-7135|doi=10.1016/j.foodcont.2012.12.001 }}</ref> Bacteria can survive long periods of time in water, animal manure, and soil, causing biofilm formation on plants or in the processing equipment.<ref>T. Tarver, "Biofilms: A Threat to Food Safety – IFT.org", Ift.org, 2016.</ref> The buildup of biofilms can affect the heat flow across a surface and increase surface corrosion and frictional resistance of fluids.<ref name=ref2>{{cite journal | vauthors = Kumar CG, Anand SK | title = Significance of microbial biofilms in food industry: a review | journal = International Journal of Food Microbiology | volume = 42 | issue = 1–2 | pages = 9–27 | date = June 1998 | pmid = 9706794 | doi = 10.1016/s0168-1605(98)00060-9 }}</ref> These can lead to a loss of energy in a system and overall loss of products.<ref name=ref2 /> Along with economic problems, biofilm formation on food poses a health risk to consumers due to the ability to make the food more resistant to disinfectants<ref name=ref1 /> As a result, from 1996 to 2010 the [[Centers for Disease Control and Prevention]] estimated 48 million foodborne illnesses per year.<ref name=ref1 /> Biofilms have been connected to about 80% of bacterial infections in the United States.<ref name=ref1 />

In [[produce]], microorganisms attach to the surfaces and biofilms develop internally.<ref name=ref1 /> During the washing process, biofilms resist sanitization and allow bacteria to spread across the produce,<ref name=ref1 /> especially via kitchen utensils.<ref>{{cite journal | vauthors = Kwok TY, Ma Y, Chua SL | title = Biofilm dispersal induced by mechanical cutting leads to heightened foodborne pathogen dissemination | journal = Food Microbiology | volume = 102 | pages = 103914 | date = April 2022 | pmid = 34809940 | doi = 10.1016/j.fm.2021.103914 | hdl = 10397/100037 | s2cid = 244234814 | hdl-access = free }}</ref> This problem is also found in ready-to-eat foods, because the foods go through limited cleaning procedures before consumption<ref name=ref1 /> Due to the perishability of dairy products and limitations in cleaning procedures, resulting in the buildup of bacteria, dairy is susceptible to biofilm formation and contamination.<ref name=ref1 /><ref name=ref2 /> The bacteria can spoil the products more readily and contaminated products pose a health risk to consumers. One species of bacteria that can be found in various industries and is a major cause of foodborne disease is ''[[Salmonella]]''.<ref name=ref3>{{cite journal | vauthors = Mizan F | year = 2015| title = Microbial biofilms in seafood: A food-hygiene challenge | journal = Food Microbiology| volume = 49| pages = 41–55| doi = 10.1016/j.fm.2015.01.009| pmid = 25846914}}</ref> Large amounts of Salmonella contamination can be found in the poultry processing industry as about 50% of ''Salmonella'' strains can produce biofilms on poultry farms.<ref name=ref1 /> ''Salmonella'' increases the risk of foodborne illnesses when the poultry products are not cleaned and cooked correctly. ''Salmonella'' is also found in the seafood industry where biofilms form from seafood borne pathogens on the seafood itself as well as in water.<ref name=ref3 /> Shrimp products are commonly affected by ''Salmonella'' because of unhygienic processing and handling techniques<ref name=ref3 /> The preparation practices of shrimp and other seafood products can allow for bacteria buildup on the products.<ref name=ref3 />

New forms of cleaning procedures are being tested to reduce biofilm formation in these processes which will lead to safer and more productive food processing industries. These new forms of cleaning procedures also have a profound effect on the environment, often releasing toxic gases into the groundwater reservoirs.<ref name=ref2 /> As a response to the aggressive methods employed in controlling biofilm formation, there are a number of novel technologies and chemicals under investigation that can prevent either the proliferation or adhesion of biofilm-secreting microbes. Latest proposed biomolecules presenting marked anti-biofilm activity include a range of metabolites such as bacterial [[rhamnolipid]]s<ref>{{cite journal| vauthors = De Araujo LV, Abreu F, Lins U, Santa Anna LM, Nitschke M, Freire DM |date=January 2011|title=Rhamnolipid and surfactin inhibit Listeria monocytogenes adhesion|journal=Food Research International|volume=44|issue=1|pages=481–488|doi=10.1016/j.foodres.2010.09.002}}</ref> and even plant-<ref>{{cite journal | vauthors = Wang X, Yao X, Zhu Z, Tang T, Dai K, Sadovskaya I, Flahaut S, Jabbouri S | title = Effect of berberine on Staphylococcus epidermidis biofilm formation | journal = International Journal of Antimicrobial Agents | volume = 34 | issue = 1 | pages = 60–6 | date = July 2009 | pmid = 19157797 | doi = 10.1016/j.ijantimicag.2008.10.033 }}</ref> and animal-derived [[alkaloid]]s.<ref>{{cite journal | vauthors = Carvalho DB, Fox EG, Santos DG, Sousa JS, Freire DM, Nogueira FC, Domont GB, Castilho LV, Machado EA | title = Fire Ant Venom Alkaloids Inhibit Biofilm Formation | journal = Toxins | volume = 11 | issue = 7 | pages = 420 | date = July 2019 | pmid = 31323790 | pmc = 6669452 | doi = 10.3390/toxins11070420 | doi-access = free }}</ref>

=== In aquaculture ===
{{Further|Aquaculture}}
[[File:Screen Shot 2017-12-13 at 1.40.19 PM.png|thumb|A biofilm from the [[Dead Sea]]]]

In [[shellfish]] and [[algal]] [[aquaculture]], [[biofouling]] microbial species tend to block nets and cages and ultimately outcompete the farmed species for space and food.<ref>{{cite journal | vauthors = Braithwaite RA, McEvoy LA | title = Marine biofouling on fish farms and its remediation | journal = Advances in Marine Biology | volume = 47 | pages = 215–252 | year = 2004 | pmid = 15596168 | doi = 10.1016/S0065-2881(04)47003-5 | isbn = 978-0-12-026148-2 }}</ref> Bacterial biofilms start the colonization process by creating microenvironments that are more favorable for biofouling species. In the marine environment, biofilms could reduce the hydrodynamic efficiency of ships and propellers, lead to pipeline blockage and sensor malfunction, and increase the weight of appliances deployed in seawater.<ref name="pmid17497196">{{cite journal | vauthors = Qian PY, Lau SC, Dahms HU, Dobretsov S, Harder T | title = Marine biofilms as mediators of colonization by marine macroorganisms: implications for antifouling and aquaculture | journal = Marine Biotechnology | volume = 9 | issue = 4 | pages = 399–410 | date = 2007 | pmid = 17497196 | doi = 10.1007/s10126-007-9001-9 | bibcode = 2007MarBt...9..399Q | s2cid = 7614961 }}</ref> Numerous studies have shown that biofilm can be a reservoir for potentially pathogenic bacteria in freshwater aquaculture.<ref name="pmid23851087">{{cite journal | vauthors = Cai W, De La Fuente L, Arias CR | title = Biofilm formation by the fish pathogen Flavobacterium columnare: development and parameters affecting surface attachment | journal = Applied and Environmental Microbiology | volume = 79 | issue = 18 | pages = 5633–42 | date = September 2013 | pmid = 23851087 | pmc = 3754160 | doi = 10.1128/AEM.01192-13 | bibcode = 2013ApEnM..79.5633C }}</ref><ref>{{cite journal|year=2004|title=Identification of bacterial pathogens in biofilms of recirculating aquaculture systems|journal=Journal of Aquatic Food Product Technology|volume=13|pages=125–133|doi=10.1300/j030v13n01_11|vauthors = King RK, Flick Jr GJ, Pierson D, Smith SA, Boardman GD, ((Coale Jr CW))|issue=1 |bibcode=2004JAFPT..13a.125K |s2cid=83791439}}</ref><ref>{{cite journal|year=2006|title=Biofilm development within a larval rearing tank of the tropical rock lobster, Panulirus ornatus|journal=Aquaculture|volume=260|issue=1–4|pages=27–38|doi=10.1016/j.aquaculture.2006.06.023|vauthors = Bourne DG, Høj L, Webster NS, Swan J, Hall MR|bibcode=2006Aquac.260...27B }}</ref><ref>{{cite journal | vauthors = Wietz M, Hall MR, Høj L | title = Effects of seawater ozonation on biofilm development in aquaculture tanks | journal = Systematic and Applied Microbiology | volume = 32 | issue = 4 | pages = 266–77 | date = July 2009 | pmid = 19446976 | doi = 10.1016/j.syapm.2009.04.001 | bibcode = 2009SyApM..32..266W }}</ref> Moreover, biofilms are important in establishing infections on the fish.<ref>{{cite journal | vauthors = Liu YS, Deng Y, Chen CK, Khoo BL, Chua SL | title = Rapid detection of microorganisms in a fish infection microfluidics platform | journal = Journal of Hazardous Materials | volume = 431 | pages = 128572 | date = June 2022 | pmid = 35278965 | doi = 10.1016/j.jhazmat.2022.128572 | bibcode = 2022JHzM..43128572L | s2cid = 247136872 }}</ref> As mentioned previously, biofilms can be difficult to eliminate even when antibiotics or chemicals are used in high doses.<ref>{{cite journal|year=1994|title=Mass mortality of Penaeus monodon larvae due to antibiotic-resistant Vibrio harveyi infection|journal=Aquaculture|volume=128|issue=3–4|pages=203–209|doi=10.1016/0044-8486(94)90309-3|vauthors = Karunasagar I, Pai R, Malathi G|bibcode=1994Aquac.128..203K }}</ref><ref name="pmid1917879">{{cite journal | vauthors = Lawrence JR, Korber DR, Hoyle BD, Costerton JW, Caldwell DE | title = Optical sectioning of microbial biofilms | journal = Journal of Bacteriology | volume = 173 | issue = 20 | pages = 6558–67 | date = October 1991 | pmid = 1917879 | pmc = 208993 | doi = 10.1128/jb.173.20.6558-6567.1991 }}</ref> The role that biofilm plays as reservoirs of bacterial fish pathogens has not been explored in detail but it certainly deserves to be studied.