Biofilms最新文献

{"title":"Power output enhancement in ceramic, mL-scale Microbial Fuel Cell","authors":"I. Gajda, Buddhi Arjuna Mendis, J. Greenman, I. Ieropoulos","doi":"10.5194/biofilms9-159","DOIUrl":"https://doi.org/10.5194/biofilms9-159","url":null,"abstract":"<p>A microbial fuel cell (MFC) is a renewable energy converter, which transforms organic biomass directly into electricity, using biofilm-electrode metabolic interaction within a bioelectrochemical cell. Efficiency of this transformation can be enhanced through miniaturisation. Miniaturisation of MFCs offers higher surface-area-to-volume ratio and improved mass transfer.</p>\u0000<p>The development of mL-scale; power dense and low cost MFCs, are of great interest in diverse areas of research, ranging from modern bio-robotics, internet-of-things devices, electrical energy generation, remote sensing to wastewater treatment and mineral recovery. The biofilms increased ability in converting organic pollutants into electric power more efficiently, makes mL-sized MFCs attractive for the development of multi-modular stacks and usable off-grid power sources with an ability of enhanced wastewater treatment. This work focuses on small scale MFCs; i) minimising the distance between feeding stream and the biofilm, ii) construction and analysis of a &#160;millilitre scale prototype, using a low cost ceramic separator for higher energy recovery efficiency and sensitivity enhancement to substrates and pollutants. The study aims to test efficient cathode modifications, using graphene ink and magnetite (Fe₃O₄); in order to improve the oxygen reduction reaction (ORR). This in turn is envisioned in an increase of the output, reaching comparable power levels to the larger MFC prototypes tested so far. The additives are chosen such that, &#160;both graphene and iron&#8211;based oxides are known from the literature to be catalysts for electrochemical processes, this work focusses on their incorporation into the open-to air cathode in novel, low cost MFC bioreactors.</p>\u0000<p>The miniaturised MFC construction constituted of an in-house fabricated small scale ceramic cylinder of internal volume of 3.88 mL. An anode, made of carbon veil fibre with a coating of activated carbon powder, was placed inside the ceramic cylinder, while the cathode was attached to the outer surface of the structure. Three types of cathodes were tested: i) activated carbon as the control (AC), ii) AC with a graphene ink coating (AC+G) and iii) AC with graphene ink and magnetite powder blend (AC+G+M). Experiments were conducted in triplicate using activated sludge and urine inoculum and thereafter continuously supplemented with 100% real human urine. The results show that the control produced up to 0.85 mW (219 W/m³), while AC+G produced 1.22 mW (312 W/m³), and AC+G+M 1.12 (288 W/m³) which is a 44 % and a 32 % increase respectively in comparison to the control. Comparison of linear sweep voltammetry (LSV) showed superior performance of both modified electrodes against the unmodified AC cathode; further resulting in an enhancement of ORR reaction rate. Power outputs from this work show over 14 times improvement in power density levels in comparison t","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49138848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneities in biofilms from clinical isolates under flow conditions","authors":"C. Cardenas, R. Rusconi","doi":"10.5194/biofilms9-113","DOIUrl":"https://doi.org/10.5194/biofilms9-113","url":null,"abstract":"Pancreatic cancer is the fourth leading cause of cancer death worldwide. The most common sign of presentation of pancreatic cancer is obstructive jaundice, which prevents the drainage of bile into the intestines and it is often associated with decreased survival in patients. Nowadays more than 70% of the patients with biliary obstructive jaundice is treated by biliary stenting; however, biliary stenting disrupts the natural anatomic barrier between the biliary and the gastrointestinal tract, strongly increasing the risk of a bacterial infection. Moreover, duodenal bacteria, by gaining access into the biliary system, can adhere to the stent surface and develop biofilms. Nevertheless, very little is known about the growth of biofilms on the stents and their role in infectious post-operative complications. In particular, the biliary system is an inherently fluid mechanical environment, where the gallbladder provides the driving pressure and the flow rate of the bile going through the ducts depends on the resistance between the gallbladder and the downstream end of the common bile duct. The average flow rate of the bile ranges between approximately 0.5 to 5 ml/min, which depends if the body is fasting or after a meal; this flow rate then corresponds – in the case for example of plastic stents, which are typically 2-4 mm in luminal diameter – to a maximum flow velocity of about 1-40 mm/s and to a shear rate at the inner surface of the stent of 1-80 s. Therefore, the mechanical stress induced by the bile flow in the stent is likely to play a significant role in the formation of biofilms, as shown by our data. Six clinically relevant isolates from preoperative biliary stents were selected to be grown inside microfluidic channels at different flow rates, in which bacterial attachment and biofilm dynamics were recorded and quantified. We found that fluid flow largely influences biofilm morphology in all the isolates, for which the conditions of flow and shear stress that trigger heterogeneities in biofilm structure have been determined. These results will help us to improve our understanding of biofilm formation in the presence of fluid dynamic environments and eventually consider optimal parameters of flow in the design of medical devices.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41692434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of an industry related biofilm into a proxy model community – Challenges around Field and lab based microbial growth analysis","authors":"Damon C. Brown, R. Turner","doi":"10.5194/biofilms9-52","DOIUrl":"https://doi.org/10.5194/biofilms9-52","url":null,"abstract":"<p>In the oil and gas industry, internal corrosion represents one of the major threats to asset lifetime and integrity. Of the types of internal corrosion, microbiologically influenced corrosion (MIC) is the most difficult to predict and monitor due to the unpredictable nature of microbial growth and the minimal metal loss resulting in through wall failure (pitting). MIC results from biofilm communities interacting directly and indirectly with the metal. Due to the structure and nature of these pipelines, directly monitoring sessile growth is impossible. As a result, most MIC monitoring is done through planktonic cells retrieved from fluid samples as a proxy for sessile populations.</p>\u0000<p>Growth curves are one of the most fundamental methods of quantitatively assessing microbial growth. In the lab, pure cultures are measured using optical densities, biomass staining, direct microscopic counting and counting colony forming units (CFU) on specialized media while more advanced techniques involve quantitative PCR (qPCR) of key genes. While PCR technologies are more easily transferred from the field to the lab, CFU counts are impossible in the field. Alternatives to the CFU are colorimetric activity assays such as &#8220;bug bottles&#8221; or biological activity reaction test (BART) bottles but aren&#8217;t sensitive and require long incubation times. More sensitive assays such as ATP measurements are also used but can be misleading as high metabolically active samples will give higher cell count equivalents than a metabolically slow community of an identical size.</p>\u0000<p>To systematically evaluate a best practice, we conducted growth curves in a lab scenario using six pure cultures and techniques predominantly used in the field to determine how these techniques compare and accurately measure microbial growth. The six species used are Acetobacterium woodii, Bacillus subtilis, Desulfovibrio vulgaris, Geoalkalibacter subterraneus, Pseudomonas putida and Thauera aromatica. The techniques used are optical density at 600 nm, ATP activity measurements using a luciferase-based assay, DNA concentration and 16S rRNA copy numbers.</p>\u0000<p>It was found that most lines of data follow the expected sigmoidal growth curve to varying degrees for all species. OD₆₀₀ readings follow the expected sigmoidal curves, exhibiting a lag phase, log growth phase and a stationary phase. ATP peaks during mid log phase and quickly declines, never showing a distinct stationary phase, while DNA concentrations closely follow the OD₆₀₀ readings but decline to death phase more rapidly. qPCR of the 16S rRNA genes revealed this data followed the same trends but was less susceptible to fluctuations.</p>\u0000<p>Assessing microbial biofilms in the environment and on anthropogenic industrial infrastructure is extremely challenging given sampling, storage and transportation to the lab.&#160; This work begins to establish best practices for growth of environmental communities ","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71171329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of temperature gradients on AOB/NOB competition in MABR biofilms","authors":"Patricia Perez, Emily Clements, C. Picioreanu, R. Nerenberg","doi":"10.5194/biofilms9-111","DOIUrl":"https://doi.org/10.5194/biofilms9-111","url":null,"abstract":"<p>The membrane aerated biofilm reactor (MABR) is an emerging wastewater treatment technology that can greatly decrease energy requirements for wastewater treatment. It consists of cassettes of air-supplying, hollow-fiber membranes that can retrofit existing activated sludge processes. MABR behavior differs from conventional biofilm processes due to the counter-diffusion of the electron donor (ammonia) and acceptor (oxygen).</p>\u0000<p>&#160;</p>\u0000<p>Partial nitrification (PN), or partial nitrification Anammox (PNA), can further improve MABR energy efficiency and cost effectiveness.&#160; To achieve this, ammonia oxidizing bacteria (AOB) must outcompete nitrite-oxidizing bacteria (NOB). &#160;High temperatures favor AOB, but it is not feasible to heat the wastewater influent.&#160; However, high-temperature compressed air can be supplied to the membrane lumen, increasing temperatures inside the biofilm without increasing the bulk temperatures. No previous research has addressed temperature gradients in biofilms, which can lead to gradients in&#160; biodegradation kinetics, diffusivities, and O₂ solubility.</p>\u0000<p>&#160;</p>\u0000<p>The objective of this research was to explore the effect of temperature gradients in MABR biofilms, especially with respect to PN. We used a one-dimensional multi-species biofilm model, which considers the MABR physical and biochemical behavior, especially with respect to temperature. The model was implemented using COMSOL Multiphysics. We also used bench-scale experiments to explore the effect of biofilm temperature gradients on MABR nitrification and PN performances and microbial community structure.</p>\u0000<p>&#160;</p>\u0000<p>Model simulations showed that MABR biofilms exposed to a temperature gradient from 20 &#186;C (biofilm interior) to 10 &#186;C (bulk liquid) had a 60% increase in nitrification rates compared with biofilms at 10 &#186;C. More importantly, the model predicted a complete out competition of NOBs within the biofilm.</p>\u0000<p>&#160;</p>\u0000<p>Preliminary experimental results confirm a significant (105%) increase in nitrification fluxes with a temperature of 30&#186;C compared to ambient temperatures (20&#186;C). Future experiments will validate the model predicted effects of biofilm temperature gradients on nitrification fluxes and microbial community structure.</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44229771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of enzymatic detergents to remove biofilms in food industries","authors":"M. Berga, Irene Ylla, M. Latorre","doi":"10.5194/biofilms9-132","DOIUrl":"https://doi.org/10.5194/biofilms9-132","url":null,"abstract":"In the last decade concern about the presence of biofilms in food processing plants has increased. Biofilms in the environment of food processing plants represent a threat to food quality, safety and shelf-life. These biofilms can host pathogenic bacteria such as Listeria, Salmonella and Campylobacter, as well as spoilage microorganisms. Additionally, biofilms show some degree of resistance to conventional detergents and disinfectants that hinders their removal and favors regrowth. Therefore, there is a need for sanitizing products and protocols that are highly efficient at removing biofilms and suitable for food processing plants. Enzymatic detergents have recently been introduced as an alternative to conventional products against biofilms in food processing plants. These detergents contain one or more enzymes that disrupt the EPS of the biofilms, making the microorganisms present in the biofilm more vulnerable to disinfectants. Enzymatic detergents have been proofed to be more efficient in degrading biofilms than conventional detergents reducing both, EPS content and bacterial counts. Finally, higher efficiency on biofilm removal was observed after completing the entire sanitizing procedure (cleaning + disinfection) using an enzymatic detergent than a conventional detergent. These tests confirm the great potential of enzymatic detergents to remove biofilms.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44443519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Driving factors for bioclogging of pores and porous media","authors":"Dorothee L. Kurz, E. Secchi, R. Stocker, J. Jiménez‐Martínez","doi":"10.5194/biofilms9-23","DOIUrl":"https://doi.org/10.5194/biofilms9-23","url":null,"abstract":"Understanding the interplay between hydrodynamics and biogeochemical processes is of growing importance in environmental applications and studies, especially in the fields of bioremediation and ecology. The majority of the microbial communities living in soil have a surface-attached lifestyle, allowing them to form biofilms. The biofilm growth influences pore geometries by clogging them and thus redirecting the flow, which in return affects biofilm development and local mass transport. After initially clogging single pores, the biofilm structure expands to larger clusters before eventually clogging the porous medium entirely. We study these processes with a soil-born microorganism, Bacillus subtilis, in microfluidic devices mimicking porous media to get a mechanistic understanding of the driving factors of bioclogging of porous media on different scales.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47775200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selective antibiofilm properties of nano-ZnO and nano-ZnO/Ag coated surfaces","authors":"Merilin Rosenberg, M. Visnapuu, H. Vija, V. Kisand, K. Kasemets, A. Kahru, A. Ivask","doi":"10.5194/biofilms9-74","DOIUrl":"https://doi.org/10.5194/biofilms9-74","url":null,"abstract":"Merilin Rosenberg, Meeri Visnapuu, Heiki Vija, Vambola Kisand, Kaja Kasemets, Anne Kahru, and Angela Ivask National Institute of Chemical Physics and Biophysics, Laboratory of Environmental Toxicology, Estonia (rosenbergmerilin@gmail.com) Tallinn University of Technology, Department of Chemistry and Biotechnology, Estonia University of Tartu, Institute of Physics, Estonia Estonian Academy of Sciences, Estonia University of Tartu, Institute of Molecular and Cell Biology, Estonia","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45149123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance imaging (MRI) as non-invasive approach for quantifying the transport of particulate organic matter within a bed of settled aerobic granules","authors":"F. Ranzinger, Maximilian Matern, M. Layer, G. Guthausen, M. Wagner, N. Derlon, H. Horn","doi":"10.5194/biofilms9-101","DOIUrl":"https://doi.org/10.5194/biofilms9-101","url":null,"abstract":"Florian Ranzinger, Maximilian Matern, Manuel Layer, Gisela Guthausen, Michael Wagner, Nicolas Derlon, and Harald Horn KIT, Engler-Bunte-Institut, Wasserchemie und Wassertechnologie, Germany (florian.ranzinger@kit.edu) Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600, Dübendorf, Switzerland Institute for Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology, Adenauerring 20b, 76131, Karlsruhe, Germany Karlsruhe Institute of Technology, Institute of Biological Interfaces (IBG-1), Hermann-von-Helmholtz-Platz 1, 76344, EggensteinLeopoldshafen, Germany DVGW Research Laboratories, Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71171276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recombinant Protein Production and Plasmid Stability in Escherichia coli Biofilms","authors":"L. Gomes, G. Monteiro, F. Mergulhão","doi":"10.5194/biofilms9-65","DOIUrl":"https://doi.org/10.5194/biofilms9-65","url":null,"abstract":"<p><em>Escherichia coli</em> biofilms have a great biotechnological potential since this organism has been one of the preferred hosts for recombinant protein production for the past decades and it has been successfully used in metabolic engineering for the production of high-value compounds.</p>\u0000<p>In a previous study, we have demonstrated that the non-induced enhanced green fluorescent protein (eGFP) expression from <em>E. coli</em> biofilm cells was 30-fold higher than in the planktonic state without any optimization of cultivation parameters [1]. The aim of the present work was to evaluate the effect of chemical induction with isopropyl &#946;-D-1-thiogalactopyranoside (IPTG) on the expression of eGFP by planktonic and biofilm cells of <em>E. coli</em> JM109(DE3) transformed with a plasmid containing a T7 promoter.</p>\u0000<p>It was shown that induction negatively affected the growth and viability of planktonic cultures, and eGFP production did not increase. Recombinant protein production was not limited by gene dosage or by transcriptional activity. Results suggest that plasmid maintenance at high copy number imposes a metabolic burden that precludes high level expression of the recombinant protein. In biofilm cells, the inducer avoided the overall decrease in the amount of expressed eGFP, although this was not correlated with the gene dosage. Higher specific production levels were always attained with biofilm cells and it seems that while induction of biofilm cells shifts their metabolism towards the maintenance of recombinant protein concentration, in planktonic cells the cellular resources are directed towards plasmid replication and growth [2].</p>\u0000<p>It is expected that this work will be of great value to elucidate the mechanisms of induction on recombinant protein production, especially in biofilm cells which have shown potential to be used as protein factories.</p>\u0000<p>&#160;</p>\u0000<p>&#160;</p>\u0000<p>References:</p>\u0000<p>[1] Gomes, L.C., & Mergulh&#227;o, F.J. (2017) Heterologous protein production in <em>Escherichia coli</em> biofilms: A non-conventional form of high cell density cultivation. <em>Process Biochemistry, 57, 1-8</em>. https://doi.org/10.1016/j.procbio.2017.03.018</p>\u0000<p>[2] Gomes, L., Monteiro, G., & Mergulh&#227;o, F. (2020). The Impact of IPTG Induction on Plasmid Stability and Heterologous Protein Expression by <em>Escherichia coli</em> Biofilms. <em>International Journal of Molecular Sciences, 21(2), 576</em>. https://doi.org/10.3390/ijms21020576</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71171467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functionalising antibiotics with nitroxides as an effective broad-spectrum biofilm eradication strategy.","authors":"Anthony D. Verderosa, K. Fairfull‐Smith, Makrina Totsika","doi":"10.5194/biofilms9-12","DOIUrl":"https://doi.org/10.5194/biofilms9-12","url":null,"abstract":"<p><strong>Background:</strong></p>\u0000<p>The adhesion of planktonic bacteria to a surface (biotic or abiotic), and their subsequent ability to aggregate into multicellular communities called biofilms, is a major driving force of failing antibiotic therapy and persistence in chronic infections caused by a variety of pathogens (e.g., <em>Pseudomonas aeruginosa</em>, <em>Escherichia coli</em>, and <em>Staphylococcus aureus)</em>&#160;and plaguing healthcare systems worldwide. Biofilms are estimated to be involved in over 80% of all microbial infections in humans, and commonly exhibit extreme resistance to conventional antimicrobial treatments. Consequently, there is an urgent need for novel antimicrobial agents, which target biofilm residing cells. Here, we present the development and evaluation of a new generation of dual-acting nitroxide functionalised antibiotics with potent biofilm eradication activity.</p>\u0000<p><strong>Methodology:</strong></p>\u0000<p>Synthetic organic chemistry was utilised to produce a new generation of nitroxide functionalised antibiotics with targeted biofilm eradication capabilities. These compounds were tested for biofilm eradication and/or dispersal of several bacterial species using the MBEC^TM device, a reproducible high-throughput static biofilm formation system. Mature biofilms were treated with serial dilutions of the specific test agent(s) and recovered bacterial numbers were quantified by absorbance spectroscopy at 600 nm or plating for viable cell counts. Treated biofilms were also stained with Live/Dead (SYTO-9/PI) bacterial viability kit and analysed by fluorescence and confocal laser scanning microscopy.</p>\u0000<p><strong>Results: </strong></p>\u0000<p>Nitroxide functionalised antibiotics exhibit potent biofilm-eradication activity against a variety of medically important pathogens, including <em>P. aeruginosa</em>, uropathogenic <em>E. coli</em>, and <em>S. aureus</em>. In Minimal Biofilm Eradication Concentration (MBEC) assays nitroxide functionalised antibiotics were 64-fold more potent against <em>S. aureus</em> biofilms, and at least 2-fold more potent against uropathogenic <em>E. coli</em> biofilms than the parent antibiotic ciprofloxacin.</p>\u0000<p><strong>Conclusions:</strong></p>\u0000<p>Currently, antibiotics are often entirely ineffective against biofilm infections. Nitroxide functionalised antibiotics represent a promising new strategy, which could circumvent the resistance of Gram-positive and Gram-negative biofilms to conventional treatments.</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44085262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}