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Journal articles on the topic 'Biofilm monitoring'
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1
Lewandowski, Z., and H. Beyenal. "Biofilm monitoring: a perfect solution in search of a problem." Water Science and Technology 47, no. 5 (March 1, 2003): 9–18. http://dx.doi.org/10.2166/wst.2003.0267.
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The main problem with monitoring biofilms is data interpretation. Biofilm heterogeneity causes monitored parameters to vary from location to location in the same biofilm, and it is difficult to assess to what extent these variations are caused by biofilm heterogeneity and to what extent they reflect other properties of the biofilm. We have used the concept of discretized biofilms, which is an integrated system of biofilm monitoring and data interpretation, to assess the effect of biofilm heterogeneity on biofilm activity. Using this approach we have estimated that a heterogeneous biofilm can be ten times more active, in terms of glucose consumption rate, than a homogeneous biofilm of the same thickness but with uniformly distributed density.
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Schmid, T., U. Panne, C. Haisch, and R. Niessner. "Biofilm monitoring by photoacoustic spectroscopy." Water Science and Technology 47, no. 5 (March 1, 2003): 25–29. http://dx.doi.org/10.2166/wst.2003.0271.
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The use of photoacoustic spectroscopy (PAS) as a new biofilm monitoring technique is presented. Growth and detachment of biofilms at three different positions inside a flow channel were monitored by photoacoustic measurements in the visible spectral range (λ = 532 nm). The experimental approach allows the investigation of the influence of various process parameters (e.g. pH or flow conditions) on growth and detachment of biofilms. In addition, the distribution of the attached biomass can be monitored by depth-resolved photoacoustic measurements.
3
Power, M. E., J. C. Araujo, J. R. van der Meer, H. Harms, and O. Wanner. "Monitoring sulfate-reducing bacteria in heterotrophic biofilms." Water Science and Technology 39, no. 7 (April 1, 1999): 49–56. http://dx.doi.org/10.2166/wst.1999.0326.
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To a laboratory reactor, in which heterotrophic biofilms were grown on stainless steel coupons under aerobic conditions, sulfate-reducing bacteria (SRB) were added in order to elucidate whether and how these microorganisms were going to establish themselves in the biofilm. Polymerase chain reaction for the dissimilatory sulfite reductase gene and in situ hybridization with probes directed against 16S ribosomal RNA were used to detect the SRB in the biofilm. Both methods proved to be suitable tools for monitoring the SRB in these experiments, which lasted seven days. In a first series of experiments, in which the SRB were added after a biofilm had already developed, the SRB could be detected only one day after addition. No evidence was found that the SRB penetrated the biofilm and established themselves in the anaerobic niches which were present. In a second series of experiments, in which the SRB were inoculated together with a seed of aerobic heterotrophic microorganisms, the SRB were present in the biofilm over the whole biofilm depth and for the duration of the experiment. The study suggests that colonization of the steel coupons by the SRB added to the bulk fluid is hampered by the already developed biofilm, even though the heterogeneous biofilm structure and anaerobic zones in the biofilm depth offer the possibility for the SRB to penetrate and establish themselves.
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Fysun, Olga, Alen Maher, Holger Brehm, Bernd Wilke, and Horst Christian Langowski. "Monitoring of Biofilm Development on Surfaces Using an Electrochemical Method." Solid State Phenomena 262 (August 2017): 492–95. http://dx.doi.org/10.4028/www.scientific.net/ssp.262.492.
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Bioleaching is the extraction of metals from ore by microorganisms. Initial attachment and formation of biofilm by microorganisms are very important for the bioleaching due to the mineral oxidation processes. However, very few techniques were proposed to monitor initial stage of biofilms in real time. Therefore, the aim of this work was to probe an electrochemical method on the bacterial biofilm model under the laboratory conditions. It was found that electrochemical method can be suggested for the real time detection of initial phase of P. polymyxa biofilm formation by observation of the potential increase. However, detection of biofilm development at late stages was not successful due to the decrease of the electrochemical potential by full coverage of the test surface. Nevertheless, this technique is supposed as a promising method for early stage detection of desirable biofilms of acidophilic iron oxidizing microorganisms in bioleaching.
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Janknecht, Peter, and Luis F. Melo. "Online Biofilm Monitoring." Reviews in Environmental Science and Bio/Technology 2, no. 2-4 (2003): 269–83. http://dx.doi.org/10.1023/b:resb.0000040461.69339.04.
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Li, J., and P. L. Bishop. "Monitoring the influence of toxic compounds on microbial denitrifying biofilm processes." Water Science and Technology 47, no. 5 (March 1, 2003): 211–16. http://dx.doi.org/10.2166/wst.2003.0323.
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Microelectrode measurements were conducted to obtain nitrate, pH and redox potential profiles within anoxic denitrifying biofilms. The influence of a toxic organic compound (acid orange 7) on biofilm microprofiles was also monitored using microelectrodes. The data provide evidence that the denitrifying biofilms were stratified into an anoxic layer and an anaerobic layer. The anaerobic zone might provide a niche for the biodegradation of recalcitrant organic compounds in biofilms. It was found that acid orange 7 and its biodegradation byproducts had only a slight impact on biofilm nitrate, pH and redox potential profiles.
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Fuchs, S., T. Haritopoulou, M. Schäfer, and M. Wilhelmi. "Heavy metals in freshwater ecosystems introduced by urban rainwater runoff - monitoring of suspended solids, river sediments and biofilms." Water Science and Technology 36, no. 8-9 (October 1, 1997): 277–82. http://dx.doi.org/10.2166/wst.1997.0679.
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Sediments, suspended solids and biofilm samples at different locations of the River Alb near Karlsruhe were analysed for their heavy metal content (Pb, Cu, Cd). The main task of this study was to validate the biofilm method by comparing the measured pollution with the results of long term monitoring programs based on sediments and suspended solid samples. All compartments of the surveyed systems showed increasing heavy metal concentrations towards highly urbanised areas. The translation of data into pollution classes detected similar pollution situations for sediments and biofilms. The presented biofilm method recommends itself as a practicable instrument for assessing the heavy metal pollution in freshwater ecosystems. The easy sampling-technique, the low variability in the detected values and the ecological relevance of biofilms are the obvious advantages of this biofilm monitoring.
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Artiga, P., V. Oyanedel, J. M. Garrido, and R. Mendez. "A novel titrimetric method for monitoring toxicity on nitrifying biofilms." Water Science and Technology 47, no. 5 (March 1, 2003): 205–9. http://dx.doi.org/10.2166/wst.2003.0321.
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A titrimetric method for monitoring toxicity in suspended biomass was applied in order to measure the activity of nitrifying biofilms and to determine the effect of several toxic compounds on the biofilm. Three typical tannery compounds, quebracho extract, NaCl and Cr+3 were selected to study their toxicity on the biofilms. The results obtained showed an acceptable repeatability of the method for all the toxicants tested with an average standard deviation of less than 10%. Biofilm systems showed higher resistance to the toxicants, when the results obtained using suspended nitrifying biomass, were compared with those found in the literature. The IC50 obtained with quebracho was 8.8 g/L of quebracho extract, while around 65% of maximum activity was attained with 8.7 g/L of NaCl or 120 mg/L Cr+3. The quebracho extract, NaCl and Cr+3 were 26%, 38% and 18%, respectively, less toxic in the biofilm system than for a suspended biomass culture.
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Sultan, Andi Rofian, Mehri Tavakol, Nicole A. Lemmens-den Toom, Peter D. Croughs, Nelianne J. Verkaik, Annelies Verbon, and Willem J. B. van Wamel. "Real time monitoring of Staphylococcus aureus biofilm sensitivity towards antibiotics with isothermal microcalorimetry." PLOS ONE 17, no. 2 (February 16, 2022): e0260272. http://dx.doi.org/10.1371/journal.pone.0260272.
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Biofilm-associated infections with Staphylococcus aureus are difficult to treat even after administration of antibiotics that according to the standard susceptibility assays are effective. Currently, the assays used in the clinical laboratories to determine the sensitivity of S. aureus towards antibiotics are not representing the behaviour of biofilm-associated S. aureus, since these assays are performed on planktonic bacteria. In research settings, microcalorimetry has been used for antibiotic susceptibility studies. Therefore, in this study we investigated if we can use isothermal microcalorimetry to monitor the response of biofilm towards antibiotic treatment in real-time. We developed a reproducible method to generate biofilm in an isothermal microcalorimeter setup. Using this system, the sensitivity of 5 methicillin-sensitive S. aureus (MSSA) and 5 methicillin-resistant S. aureus (MRSA) strains from different genetic lineages were determined towards: flucloxacillin, cefuroxime, cefotaxime, gentamicin, rifampicin, vancomycin, levofloxacin, clindamycin, erythromycin, linezolid, fusidic acid, co-trimoxazole, and doxycycline. In contrast to conventional assays, our calorimetry-based biofilm susceptibility assay showed that S. aureus biofilms, regardless MSSA or MRSA, can survive the exposure to the maximum serum concentration of all tested antibiotics. The only treatment with a single antibiotic showing a significant reduction in biofilm survival was rifampicin, yet in 20% of the strains, emerging antibiotic resistance was observed. Furthermore, the combination of rifampicin with flucloxacillin, vancomycin or levofloxacin was able to prevent S. aureus biofilm from becoming resistant to rifampicin. Isothermal microcalorimetry allows real-time monitoring of the sensitivity of S. aureus biofilms towards antibiotics in a fast and reliable way.
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Savilov, E. D., E. V. Anganova, O. A. Noskova, and A. V. Dukhanina. "Bacteria Biofilms in Purulent-Septic Infections." Acta Biomedica Scientifica 4, no. 5 (November 14, 2019): 38–42. http://dx.doi.org/10.29413/abs.2019-4.5.6.
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The causative agents of many infectious diseases can exist in the form of biofilms.The aim of the workis to study of the frequency of occurrence and the degree of activity of biofilm formation of microorganisms isolated from different locus in purulent-septic infections.Materials and methods.Fifteen strains isolated from patients with purulent-septic infections were examined. Biofilms were determined by the ability to adsorption a crystalviolet to ethanol.Results. 73,3 ± 11,4 % strains had biofilms (including gram-negative bacteria – 69,2 ± 11,9 %; Staphylococcus – 100,0 %; p < 0,05).The degree of activity of formation of biofilm by gram-negative bacteria was higher than Staphylococcus (0,302 ± 0,04 и 0,134 ± 0,01 units of optical density; p < 0,01). The highest activity of formation of biofilm was detected in K. pneumoniae isolated from patients with sepsis. Strains from clinically important locus (blood, sputum, wound discharge, abdominal fluid) had biofilms in 75,0 %; from locus of monitoring – 66,7 %. The pathogens isolated from locus of the monitoring were characterized by an average degree of activity of biofilm formation (0,180–0,360 units of optical density). Strains from clinically important locus (blood and sputum from patients with sepsis) had a highdegree of biofilm formation (more than 0,360 units of optical density). Conclusion. In most cases, strains were characterized by the presence of biofilms and differed in degrees activity of biofilm formation depending on locus.
11
Bohn, A., B. Zippel, J. S. Almeida, and J. B. Xavier. "Stochastic modeling for characterisation of biofilm development with discrete detachment events (sloughing)." Water Science and Technology 55, no. 8-9 (April 1, 2007): 257–64. http://dx.doi.org/10.2166/wst.2007.266.
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The monitoring of biofilm development at a small-scale is often observed to be a stochastic process. This raises important issues concerning the reproducibility of biofilm growth monitoring experiments. By realising that there are limits to the latter, a model of biofilm accumulation curves that takes into account the dynamics of seemingly random fluctuations resulting from sloughing events is proposed. The model is derived from a stochastic differential equation (SDE) based on the logistic equation, adding a stochastic term for the sloughing events and measurement noise. Experimental light absorbance data that correlate with biofilm biomass obtained from the development of phototrophic biofilms are analysed to illustrate the use of SDE modeling.
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CHUMKHUNTHOD, P., H. SCHRAFT, and M. W. GRIFFITHS. "Rapid Monitoring Method to Assess Efficacy of Sanitizers against Pseudomonas putida Biofilms." Journal of Food Protection 61, no. 8 (August 1, 1998): 1043–46. http://dx.doi.org/10.4315/0362-028x-61.8.1043.
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Biofilms of luminescent Pseudomonas putida were developed on rubber surfaces by incubation in brain heart infusion (BHI) broth. Scanning electron microscopy (SEM) and epifluorescence microscopy (EFM) were used to examine biofilm formation. To test the efficacy of two sanitizers commonly employed in dairy plants for CIP (cleaning in place) procedures, a novel bioluminescence method and aerobic plating were used to enumerate cells. Immediately after the sanitizer treatments an apparent 5-log reduction of biofilm-associated cells was determined. However, when the samples were resuscitated for 18 h in BHI broth, high numbers of cells were detected which reached levels close to those of nontreated controls. The results demonstrated that neither sanitizer could completely eliminate biofilm-associated P. putida. The microbial bioluminescence method proved to be the best way for assessing effectiveness of sanitizers against microbial biofilms.
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Simões, Lúcia Chaves, Manuel Simões, and Maria João Vieira. "A comparative study of drinking water biofilm monitoring with flow cell and Propella™ bioreactors." Water Supply 12, no. 3 (May 1, 2012): 334–42. http://dx.doi.org/10.2166/ws.2011.139.
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Monitoring of drinking water (DW) biofilm formation under different process conditions was performed using two distinct bioreactors: a Propella™ and a flow cell system. Biofilms were grown on polyvinyl chloride (PVC) and stainless steel (SS) coupons under laminar (Reynolds number: 2000) and turbulent (Reynolds number: 11000) flow. The parameters analysed were the numbers of total and cultivable bacteria. The impact of different process conditions was assessed after the biofilms reached steady-state. The number of total bacteria was mostly higher than those cultivable. Biofilm steady-state was achieved in 3 days in both bioreactors with adhesion surfaces under turbulent flow. Under laminar flow it was only achieved in 6 days. The numbers of total and cultivable bacteria in turbulent flow-generated biofilms were similar in both bioreactors, regardless of the adhesion surface tested. Under laminar flow, the Propella™ bioreactor allowed the formation of steady-state biofilms with a higher number of total and cultivable bacteria than the flow cell system. Comparing the effects of the flow regime on biofilm accumulation, only turbulent flow-generated biofilms formed on the flow cell system had a higher amount of total and cultivable bacteria than those formed under laminar flow. In terms of adhesion surface effects, a higher number of total and cultivable cells were found on PVC surfaces compared to SS when biofilms were formed in the flow cell system. Biofilm formation on PVC and SS was similar in the Propella™ system for both flow regimes.
14
Pang, Chee Meng, and Wen-Tso Liu. "Biological Filtration Limits Carbon Availability and Affects Downstream Biofilm Formation and Community Structure." Applied and Environmental Microbiology 72, no. 9 (September 2006): 5702–12. http://dx.doi.org/10.1128/aem.02982-05.
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ABSTRACT Carbon removal strategies have gained popularity in the mitigation of biofouling in water reuse processes, but current biofilm-monitoring practices based on organic-carbon concentrations may not provide an accurate representation of the in situ biofilm problem. This study evaluated a submerged microtiter plate assay for direct and rapid monitoring of biofilm formation by subjecting the plates to a continuous flow of either secondary effluent (SE) or biofilter-treated secondary effluent (BF). This method was very robust, based on a high correlation (R 2 = 0.92) between the biomass (given by the A 600 in the microtiter plate assay) and the biovolume (determined from independent biofilms developed on glass slides under identical conditions) measurements, and revealed that the biomasses in BF biofilms were consistently lower than those in SE biofilms. The influence of the organic-carbon content on the biofilm community composition and succession was further evaluated using molecular tools. Terminal restriction fragment length polymorphism analysis of 16S rRNA genes revealed a group of pioneer colonizers, possibly represented by Sphingomonadaceae and Caulobacter organisms, to be common in both SE and BF biofilms. However, differences in organic-carbon availabilities in the two water samples eventually led to the selection of distinct biofilm communities. Alphaproteobacterial populations were confirmed by fluorescence in situ hybridization to be enriched in SE biofilms, while Betaproteobacteria were dominant in BF biofilms. Cloning analyses further demonstrated that microorganisms adapted for survival under low-substrate conditions (e.g., Aquabacterium, Caulobacter, and Legionella) were preferentially selected in the BF biofilm, suggesting that carbon limitation strategies may not achieve adequate biofouling control in the long run.
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Klopper, Kyle B., Elanna Bester, and Gideon M. Wolfaardt. "Listeria monocytogenes Biofilms Are Planktonic Cell Factories despite Peracetic Acid Exposure under Continuous Flow Conditions." Antibiotics 12, no. 2 (January 19, 2023): 209. http://dx.doi.org/10.3390/antibiotics12020209.
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Listeria monocytogenes biofilms are ubiquitous in the food-processing environment, where they frequently show resistance against treatment with disinfectants such as peracetic acid (PAA) due to sub-lethal damage resulting in biofilm persistence or the formation of secondary biofilms. L. monocytogenes serovar ½a EGD-e biofilms were cultivated under continuous flow conditions at 10 °C, 22 °C, and 37 °C and exposed to industrially relevant PAA concentrations. The effect of PAA on biofilm metabolic activity and biomass was monitored in real-time using the CEMS-BioSpec system, in addition to daily measurement of biofilm-derived planktonic cell production. Biofilm-derived planktonic cell yields proved to be consistent with high yields during biofilm establishment (≥106 CFU.mL−1). The exposure of biofilms to the minimum inhibitory PAA concentration (0.16%) resulted in only a brief disruption in whole-biofilm metabolic activity and biofilm biomass accumulation. The recovered biofilm accumulated more biomass and greater activity, but cell yields remained similar. Increasing concentrations of PAA (0.50%, 1.5%, and 4.0%) had a longer-lasting inhibitory effect. Only the maximum dose resulted in a lasting inhibition of biofilm activity and biomass–a factor that needs due consideration in view of dilution in industrial settings. Better disinfection monitoring tools and protocols are required to adequately address the problem of Listeria biofilms in the food-processing environment, and more emphasis should be placed on biofilms serving as a “factory” for cell proliferation rather than only a survival mechanism.
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Araujo, J. C., G. Brucha, J. R. Campos, and R. F. Vazoller. "Monitoring the development of anaerobic biofilms using fluorescent in situ hybridization and confocal laser scanning microscopy." Water Science and Technology 41, no. 12 (June 1, 2000): 69–77. http://dx.doi.org/10.2166/wst.2000.0243.
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In this study we investigated the development of anaerobic biofilm using a laboratory reactor. We were especially interested in comparing the organization of anaerobic cells (particularly those that are very common in domestic sewage sludge) in a hydrophilic (glass) versus a hydrophobic (polypropylene) surface. Fluorescent in situ hybridization (FISH) with domain and group specific probes directed against 16S ribosomal RNA were used to quantify microbial composition in the biofilm. FISH and confocal laser scanning microscopy (CLSM) were used to elucidate spatial distribution of microbes in the biofilms. Two experiments were carried out, one with pure methanogenic organisms and the other with a microbial anaerobic consortium. The pure methanogen cultures, Methanobacterium formicicum (DSM 1535); Methanosaeta concilli (DSM 3671) and Methanosarcina barkeri (DSM 800) were used to seed the modified Robbins Device (MRD) to allow the development of biofilms on polypropylene and glass surfaces during the 9-days experiment. The results showed that all the three species were colonizing both surfaces after two and nine days of experimental period. In another experiment, with polypropylene coupons only, MRD was seeded with a microbial anaerobic consortium and biofilm formation was studied during 11 days. At the end of this period, the biofilms generated were of uneven thickness with areas of minimal or no surface coverage and areas where the biofilm attained a thickness of 7.0 to 9.0 μm as revealed by CLSM. The results showed that the modified Robbins Device together with the fluorescent in situ hybridization and confocal laser scanning microscopy are suitable tools to study anaerobic biofilm development in different kinds of support materials.
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Alvarez-Ordóñez, Avelino, Laura M. Coughlan, Romain Briandet, and Paul D. Cotter. "Biofilms in Food Processing Environments: Challenges and Opportunities." Annual Review of Food Science and Technology 10, no. 1 (March 25, 2019): 173–95. http://dx.doi.org/10.1146/annurev-food-032818-121805.
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This review examines the impact of microbial communities colonizing food processing environments in the form of biofilms on food safety and food quality. The focus is both on biofilms formed by pathogenic and spoilage microorganisms and on those formed by harmless or beneficial microbes, which are of particular relevance in the processing of fermented foods. Information is presented on intraspecies variability in biofilm formation, interspecies relationships of cooperativism or competition within biofilms, the factors influencing biofilm ecology and architecture, and how these factors may influence removal. The effect on the biofilm formation ability of particular food components and different environmental conditions that commonly prevail during food processing is discussed. Available tools for the in situ monitoring and characterization of wild microbial biofilms in food processing facilities are explored. Finally, research on novel agents or strategies for the control of biofilm formation or removal is summarized.
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Schaefer, L. M., V. S. Brözel, and S. N. Venter. "Fate of Salmonella Typhimurium in laboratory-scale drinking water biofilms." Journal of Water and Health 11, no. 4 (August 6, 2013): 629–35. http://dx.doi.org/10.2166/wh.2013.208.
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Investigations were carried out to evaluate and quantify colonization of laboratory-scale drinking water biofilms by a chromosomally green fluorescent protein (gfp)-tagged strain of Salmonella Typhimurium. Gfp encodes the green fluorescent protein and thus allows in situ detection of undisturbed cells and is ideally suited for monitoring Salmonella in biofilms. The fate and persistence of non-typhoidal Salmonella in simulated drinking water biofilms was investigated. The ability of Salmonella to form biofilms in monoculture and the fate and persistence of Salmonella in a mixed aquatic biofilm was examined. In monoculture S. Typhimurium formed loosely structured biofilms. Salmonella colonized established multi-species drinking water biofilms within 24 hours, forming micro-colonies within the biofilm. S. Typhimurium was also released at high levels from the drinking water-associated biofilm into the water passing through the system. This indicated that Salmonella could enter into, survive and grow within, and be released from a drinking water biofilm. The ability of Salmonella to survive and persist in a drinking water biofilm, and be released at high levels into the flow for recolonization elsewhere, indicates the potential for a persistent health risk to consumers once a network becomes contaminated with this bacterium.
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Netsch, Andreas, Harald Horn, and Michael Wagner. "On-Line Monitoring of Biofilm Accumulation on Graphite-Polypropylene Electrode Material Using a Heat Transfer Sensor." Biosensors 12, no. 1 (December 30, 2021): 18. http://dx.doi.org/10.3390/bios12010018.
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Biofilms growing on electrodes are the heart piece of bioelectrochemical systems (BES). Moreover, the biofilm morphology is key for the efficient performance of BES and must be monitored and controlled for a stable operation. For the industrial use of BES (i.e., microbial fuel cells for energy production), monitoring of the biofilm accumulation directly on the electrodes during operation is desirable. In this study a commercially available on-line heat transfer biofilm sensor is applied to a graphite-polypropylene (C-PP) pipe and compared to its standard version where the sensor is applied to a stainless-steel pipe. The aim was to investigate the transferability of the sensor to a carbonaceous material (C-PP), that are preferably used as electrode materials for bioelectrochemical systems, thereby enabling biofilm monitoring directly on the electrode surface. The sensor signal was correlated to the gravimetrically determined biofilm thickness in order to identify the sensitivity of the sensor for the detection and quantification of biofilm on both materials. Results confirmed the transferability of the sensor to the C-PP material, despite the sensor sensitivity being decreased by a factor of approx. 5 compared to the default biofilm sensor applied to a stainless-steel pipe.
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Romero, Danitza Xiomara, Oscar VÃctor Cárdenas, and MarÃa Teresa Ãlvarez. "Detection of ALS3 and EAP1 gene expresssion in Candida albicans and Candida maltosa biofilms by FISH." JOURNAL OF ADVANCES IN BIOTECHNOLOGY 6, no. 2 (December 14, 2016): 848–57. http://dx.doi.org/10.24297/jbt.v6i2.4374.
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Biofilm is regarded as universal forms of microorganism life in aquatic and industrial wastewater systems as well as in a large number of environments and medical devices relevant for public health, where the exact mechanisms by which biofilm-associated microorganisms elicit infection diseases are still poorly understood. Candida biofilm formation is regulated by different mechanisms where adhesins play a clue role in the yeast attachment to certain surfaces. These adhesins are encoding by ALS3, HWP1 and EAP1 genes among others and they are also considered as Candida virulence factors. Methodologies use to study biofilm productions are intended to verify the biofilm composition, formation steps, tridimensional structure and might facilitate the monitoring of biofilm regarding, antibiotic resistance, degradations, inhibitors, enhanciement biofilm formation and other features. Here, FISH expression a modified method to detect gene expression in situ was used in order to detect ALS3, HWP1 and EAP1 in C. albicans and C. maltosa biofilms, constituting a useful tool to monitor biofilm formations. In this regard, ALS3 expression was identified in C. albicans and C. maltosa biofilms.
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Brunetti, Giuseppe, Donato Conteduca, Mario Nicola Armenise, and Caterina Ciminelli. "Novel Micro-Nano Optoelectronic Biosensor for Label-Free Real-Time Biofilm Monitoring." Biosensors 11, no. 10 (September 29, 2021): 361. http://dx.doi.org/10.3390/bios11100361.
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According to the World Health Organization forecasts, AntiMicrobial Resistance (AMR) is expected to become one of the leading causes of death worldwide in the following decades. The rising danger of AMR is caused by the overuse of antibiotics, which are becoming ineffective against many pathogens, particularly in the presence of bacterial biofilms. In this context, non-destructive label-free techniques for the real-time study of the biofilm generation and maturation, together with the analysis of the efficiency of antibiotics, are in high demand. Here, we propose the design of a novel optoelectronic device based on a dual array of interdigitated micro- and nanoelectrodes in parallel, aiming at monitoring the bacterial biofilm evolution by using optical and electrical measurements. The optical response given by the nanostructure, based on the Guided Mode Resonance effect with a Q-factor of about 400 and normalized resonance amplitude of about 0.8, allows high spatial resolution for the analysis of the interaction between planktonic bacteria distributed in small colonies and their role in the biofilm generation, calculating a resonance wavelength shift variation of 0.9 nm in the presence of bacteria on the surface, while the electrical response with both micro- and nanoelectrodes is necessary for the study of the metabolic state of the bacteria to reveal the efficacy of antibiotics for the destruction of the biofilm, measuring a current change of 330 nA when a 15 µm thick biofilm is destroyed with respect to the absence of biofilm.
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Artyukh, T. V., T. N. Sokolova, and V. M. Sheibak. "MODERN METHODS FOR RESEARCHING MICROBIAL BIOFILMS OF THE ENTEROBACTERIACEAE FAMILY." Hepatology and Gastroenterology 5, no. 1 (June 10, 2021): 30–36. http://dx.doi.org/10.25298/2616-5546-2021-5-1-30-36.
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The article outlines the main methods of studying microbial biofilms, which make it possible to reveal: the patterns of biofilm formation by microorganisms of the Enterobacteriaceae family, genetic programs regulating the processes of film formation, qualitative and quantitative characteristics of the components of microbial communities, the influence of external factors on the stages of biofilm formation and dispersion. The study of the phenomenon of film formation in combination with monitoring the resistance of intestinal microorganisms in the biofilm to antibacterial drugs will make it possible to get closer to understanding the role of biofilms in the course of infectious processes of a microbial origin.
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Ronan, Patrick, Otini Kroukamp, Steven N. Liss, and Gideon Wolfaardt. "A Novel System for Real-Time, In Situ Monitoring of CO2 Sequestration in Photoautotrophic Biofilms." Microorganisms 8, no. 8 (July 31, 2020): 1163. http://dx.doi.org/10.3390/microorganisms8081163.
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Climate change brought about by anthropogenic CO2 emissions has created a critical need for effective CO2 management solutions. Microalgae are well suited to contribute to efforts aimed at addressing this challenge, given their ability to rapidly sequester CO2 coupled with the commercial value of their biomass. Recently, microalgal biofilms have garnered significant attention over the more conventional suspended algal growth systems, since they allow for easier and cheaper biomass harvesting, among other key benefits. However, the path to cost-effectiveness and scaling up is hindered by a need for new tools and methodologies which can help evaluate, and in turn optimize, algal biofilm growth. Presented here is a novel system which facilitates the real-time in situ monitoring of algal biofilm CO2 sequestration. Utilizing a CO2-permeable membrane and a tube-within-a-tube design, the CO2 sequestration monitoring system (CSMS) was able to reliably detect slight changes in algal biofilm CO2 uptake brought about by light–dark cycling, light intensity shifts, and varying amounts of phototrophic biomass. This work presents an approach to advance our understanding of carbon flux in algal biofilms, and a base for potentially useful innovations to optimize, and eventually realize, algae biofilm-based CO2 sequestration.
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Flemming, H. C. "Role and levels of real-time monitoring for successful anti-fouling strategies - an overview." Water Science and Technology 47, no. 5 (March 1, 2003): 1–8. http://dx.doi.org/10.2166/wst.2003.0265.
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Biofouling is a biofilm problem and any anti-fouling strategy will be greatly improved if the site and extent of biofilm growth can be monitored. A suitable monitoring system will provide early warning capacity and allow for specific optimization of countermeasures. As water samples do not give reliable information about biofilms, surface sampling is mandatory. Conventional biofilm monitoring techniques rely on removal of material from representative sites or on analysis of test surfaces which have been exposed. This procedure is time consuming and, depending on the parameters to be measured, requires skilled laboratory personnel. There is a strong demand for direct, on-line, in situ, continuous, non-destructive real-time information about biofilms in a system. Such demands can only be fulfilled by physical or physico-chemical methods, a number of which have already been successfully applied for biofilm monitoring. It is important, however, to be aware of the actual parameter they refer to in order to interpret the data properly. Three levels of information can be identified: (i) systems which detect increase and decrease of material accumulating on a surface but cannot differentiate between biomass and other components of a deposit, (ii) systems which provide biological information and distinguish between biotic and abiotic material, and (iii) systems which provide detailed chemical information. Examples for all three levels are presented and discussed.
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Hrubanova, Kamila, Vladislav Krzyzanek, Jana Nebesarova, Filip Ruzicka, Zdenek Pilat, and Ota Samek. "Monitoring Candida parapsilosis and Staphylococcus epidermidis Biofilms by a Combination of Scanning Electron Microscopy and Raman Spectroscopy." Sensors 18, no. 12 (November 22, 2018): 4089. http://dx.doi.org/10.3390/s18124089.
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The biofilm-forming microbial species Candida parapsilosis and Staphylococcus epidermidis have been recently linked to serious infections associated with implanted medical devices. We studied microbial biofilms by high resolution scanning electron microscopy (SEM), which allowed us to visualize the biofilm structure, including the distribution of cells inside the extracellular matrix and the areas of surface adhesion. We compared classical SEM (chemically fixed samples) with cryogenic SEM, which employs physical sample preparation based on plunging the sample into various liquid cryogens, as well as high-pressure freezing (HPF). For imaging the biofilm interior, we applied the freeze-fracture technique. In this study, we show that the different means of sample preparation have a fundamental influence on the observed biofilm structure. We complemented the SEM observations with Raman spectroscopic analysis, which allowed us to assess the time-dependent chemical composition changes of the biofilm in vivo. We identified the individual spectral peaks of the biomolecules present in the biofilm and we employed principal component analysis (PCA) to follow the temporal development of the chemical composition.
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Persyn, Aranka, Ona Rogiers, Matthias Brock, Greetje Vande Velde, Mohamed Lamkanfi, Ilse D. Jacobsen, Uwe Himmelreich, Katrien Lagrou, Patrick Van Dijck, and Soňa Kucharíková. "Monitoring of Fluconazole and Caspofungin Activity against In Vivo Candida glabrata Biofilms by Bioluminescence Imaging." Antimicrobial Agents and Chemotherapy 63, no. 2 (November 12, 2018): e01555-18. http://dx.doi.org/10.1128/aac.01555-18.
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ABSTRACT Candida glabrata can attach to various medical implants and forms thick biofilms despite its inability to switch from yeast to hyphae. The current in vivo C. glabrata biofilm models only provide limited information about colonization and infection and usually require animal sacrifice. To gain real-time information from individual BALB/c mice, we developed a noninvasive imaging technique to visualize C. glabrata biofilms in catheter fragments that were subcutaneously implanted on the back of mice. Bioluminescent C. glabrata reporter strains (lucOPT 7/2/4 and lucOPT 8/1/4), free of auxotrophic markers, expressing a codon-optimized firefly luciferase were generated. A murine subcutaneous model was used to follow real-time in vivo biofilm formation in the presence and absence of fluconazole and caspofungin. The fungal load in biofilms was quantified by CFU counts and by bioluminescence imaging (BLI). C. glabrata biofilms formed within the first 24 h, as documented by the increased number of device-associated cells and elevated bioluminescent signal compared with adhesion at the time of implant. The in vivo model allowed monitoring of the antibiofilm activity of caspofungin against C. glabrata biofilms through bioluminescent imaging from day four after the initiation of treatment. Contrarily, signals emitted from biofilms implanted in fluconazole-treated mice were similar to the light emitted from control-treated mice. This study gives insights into the real-time development of C. glabrata biofilms under in vivo conditions. BLI proved to be a dynamic, noninvasive, and sensitive tool to monitor continuous biofilm formation and activity of antifungal agents against C. glabrata biofilms formed on abiotic surfaces in vivo.
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Schlafer, Sebastian, Javier E. Garcia, Matilde Greve, Merete K. Raarup, Bente Nyvad, and Irene Dige. "Ratiometric Imaging of Extracellular pH in Bacterial Biofilms with C-SNARF-4." Applied and Environmental Microbiology 81, no. 4 (December 12, 2014): 1267–73. http://dx.doi.org/10.1128/aem.02831-14.
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ABSTRACTpH in the extracellular matrix of bacterial biofilms is of central importance for microbial metabolism. Biofilms possess a complex three-dimensional architecture characterized by chemically different microenvironments in close proximity. For decades, pH measurements in biofilms have been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit the monitoring of horizontal pH gradients in biofilms in real time. Quantitative fluorescence microscopy can overcome these problems, but none of the hitherto employed methods differentiated accurately between extracellular and intracellular microbial pH and visualized extracellular pH in all areas of the biofilms. Here, we developed a method to reliably monitor extracellular biofilm pH microscopically with the ratiometric pH-sensitive dye C-SNARF-4, choosing dental biofilms as an example. Fluorescent emissions of C-SNARF-4 can be used to calculate extracellular pH irrespective of the dye concentration. We showed that at pH values of <6, C-SNARF-4 stained 15 bacterial species frequently isolated from dental biofilm and visualized the entire bacterial biomass inin vivo-grown dental biofilms with unknown species composition. We then employed digital image analysis to remove the bacterial biomass from the microscopic images and adequately calculate extracellular pH values. As a proof of concept, we monitored the extracellular pH drop inin vivo-grown dental biofilms fermenting glucose. The combination of pH ratiometry with C-SNARF-4 and digital image analysis allows the accurate monitoring of extracellular pH in bacterial biofilms in three dimensions in real time and represents a significant improvement to previously employed methods of biofilm pH measurement.
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Flemming, Hans-Curt, Adriana Tamachkiarowa, Joachim Klahre, and Jürgen Schmitt. "Monitoring of fouling and biofouling in technical systems." Water Science and Technology 38, no. 8-9 (October 1, 1998): 291–98. http://dx.doi.org/10.2166/wst.1998.0818.
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Biofouling is a problem in many different industrial fields, causing damage of product or interfering with production processes, ranging from drinking and purified water systems to paper manufacture, heat exchange or cosmetics, pharmaceutical, medical and electronic device industries. Timely countermeasures, optimization and efficacy control depend on monitoring of biofilm growth on surfaces. As water samples give no information about site and extent of biofilms, surface sampling is mandatory. The information about biofilm development should be recorded on line, in real time and non destructively in order to permit the kinetics of deposition or removal to be followed. Three physical methods are presented here: i) a fiber optical device, ii) a differential turbidity measurement device, and iii) an FTIR flow cell. The first two methods are based on light reflectance and detect the deposition of reflecting material. Thus, they are not specific for biofilms but they allow us to detect deposit formation in situ, non destructively and in real time. The third method gives information about the chemical nature of the deposit, allowing us to identify biological material. However, this increase of information requires a significantly higher technical effort.
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Keller, Sara, Gareth LuTheryn, Michael Gray, Eleanor P. Stride, Robin O. Cleveland, and Constantin Coussios. "Spatio-temporal evaluation of anti-biofilm cavitation activity by passive acoustic mapping." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A247—A248. http://dx.doi.org/10.1121/10.0016162.
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Bacterial biofilms present a major challenge to achieving effective antibiotic therapy, as these sessile communities of microbes confer protection to bacteria by decreasing antibiotic efficacy. Focused ultrasound can mechanically disrupt biofilms, offering a new ‘drug-free’ antibiotic paradigm. The goal of this work is to validate, quantify, and optimize the role of acoustic cavitation in the biofilm disruption process through spatiotemporal monitoring of cavitation activity. A clinical isolate strain of Staphylococcus aureus from native valve endocarditis was cultured for 72 hours within a flow channel to form a biofilm. A 1.1 MHz spherically focused transducer was used to expose the biofilm from below at a 45° angle. The in situ acoustic field was characterized with a fibre-optic hydrophone. A calibrated 5–11 MHz linear array was placed 25 mm above the biofilm in order to record acoustic emissions during biofilm disruption from which passive acoustic maps of cavitation could be derived. Biofilms were exposed to 4.5 MPa peak rarefactional pressure (derated), 10,000 cycles, at a 1 Hz PRF. Qualitative reduction of biofilms was assessed by live/dead staining with Syto 9/propidium iodide, which was correlated with cavitation activity observed in the passive acoustic maps.
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Liu, Hong, Xun Liu, and Ning Ding. "An Innovative in Situ Monitoring of Sulfate Reduction within a Wastewater Biofilm by H2S and SO42− Microsensors." International Journal of Environmental Research and Public Health 17, no. 6 (March 19, 2020): 2023. http://dx.doi.org/10.3390/ijerph17062023.
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Microelectrodes can be used to obtain chemical profiles within biofilm microenvironments. For example, sulfate (SO42−) and hydrogen sulfide (H2S) microelectrodes can be used to study sulfate reduction activity in this context. However, there is no SO42− microelectrode available for studying sulfate reduction in biofilms. In this study, SO42− and H2S microelectrodes were fabricated and applied in the measurement of a wastewater membrane-aerated biofilm (MAB) to investigate the in situ sulfate reduction activity. Both the SO42− and H2S microelectrodes with a tip diameter of around 20 micrometers were successfully developed and displayed satisfying selectivity to SO42− and H2S, respectively. The Nernstian slopes of calibration curves of the fabricated SO42− electrodes were close to −28.1 mV/decade, and the R2 values were greater than 98%. Within the selected concentration range from 10−5 M (0.96 mg/L) to 10−2 M (960 mg/L), the response of the SO42− microelectrode was log-linearly related to its concentration. The successfully fabricated SO42− microelectrode was combined with the existing H2S microelectrode and applied on an environmental wastewater biofilm sample to investigate the sulfate reduction activity within it. The H2S and SO42− microelectrodes showed stable responses and good performance, and the decrease of SO42− with an accompanying increased of H2S within the biofilm indicated the in situ sulfate reduction activity. The application of combined SO42− and H2S microelectrodes in wastewater biofilms could amend the current understanding of sulfate reduction and sulfur oxidation within environmental biofilms based on only H2S microelectrodes.
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Ntarlagiannis, Dimitrios, and Andrew Ferguson. "SIP response of artificial biofilms." GEOPHYSICS 74, no. 1 (January 2009): A1—A5. http://dx.doi.org/10.1190/1.3031514.
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In recent years, research into the use of geophysical methods for monitoring microbial activity within the subsurface has advanced. One of the most promising methods, induced polarization (IP), has indirectly shown sensitivity to changes in the presence of microbial cells and especially biofilms. The aim of this study is to conclusively show, and quantify if possible, the effect of biofilm accumulation on IP signals. To ensure the controlled formation of biofilm we created an “artificial” alginate gel biofilm, which was introduced into an experimental column at varying amounts. The IP response was measured throughout. Our initial results showed that the IP method is sensitive to biofilm accumulation, after a certain point, and could potentially be used to monitor such microbial structures remotely. Further research with real biofilms under more natural conditions is needed to validate our results.
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Zimmerleiter, Robert, Elisabeth Leiss-Holzinger, Eva Maria Wagner, Kathrin Kober-Rychli, Martin Wagner, and Markus Brandstetter. "Inline biofilm monitoring based on near-infrared spectroscopy with ultracompact spectrometer technology." NIR news 31, no. 7-8 (December 2020): 9–13. http://dx.doi.org/10.1177/0960336020978716.
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In this article, we demonstrate a promising inline near-infrared measurement scheme for 24/7 biofilm monitoring based on cost-effective microelectromechanical system-based spectrometer technology. The shown near-infrared spectral data, acquired at a beer-canning line during a representative time span of 10 days, are analyzed by means of principal component analysis and the performance of the monitoring system and its capability to identify biofilms on its sensor surface are investigated by comparing spectral response with results of offline polymerase chain reaction measurements of smear samples. Correlations between presence of a biofilm and its thickness with scores on PC1 and PC2, respectively, were observed.
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Islam, M. Shahinoor, Yanyan Zhang, Kerry N. McPhedran, Yang Liu, and Mohamed Gamal El-Din. "Next-Generation Pyrosequencing Analysis of Microbial Biofilm Communities on Granular Activated Carbon in Treatment of Oil Sands Process-Affected Water." Applied and Environmental Microbiology 81, no. 12 (April 3, 2015): 4037–48. http://dx.doi.org/10.1128/aem.04258-14.
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ABSTRACTThe development of biodegradation treatment processes for oil sands process-affected water (OSPW) has been progressing in recent years with the promising potential of biofilm reactors. Previously, the granular activated carbon (GAC) biofilm process was successfully employed for treatment of a large variety of recalcitrant organic compounds in domestic and industrial wastewaters. In this study, GAC biofilm microbial development and degradation efficiency were investigated for OSPW treatment by monitoring the biofilm growth on the GAC surface in raw and ozonated OSPW in batch bioreactors. The GAC biofilm community was characterized using a next-generation 16S rRNA gene pyrosequencing technique that revealed that the phylumProteobacteriawas dominant in both OSPW and biofilms, with further in-depth analysis showing higher abundances ofAlpha- andGammaproteobacteriasequences. Interestingly, many known polyaromatic hydrocarbon degraders, namely,Burkholderiales,Pseudomonadales,Bdellovibrionales, andSphingomonadales, were observed in the GAC biofilm. Ozonation decreased the microbial diversity in planktonic OSPW but increased the microbial diversity in the GAC biofilms. Quantitative real-time PCR revealed similar bacterial gene copy numbers (>109gene copies/g of GAC) for both raw and ozonated OSPW GAC biofilms. The observed rates of removal of naphthenic acids (NAs) over the 2-day experiments for the GAC biofilm treatments of raw and ozonated OSPW were 31% and 66%, respectively. Overall, a relatively low ozone dose (30 mg of O3/liter utilized) combined with GAC biofilm treatment significantly increased NA removal rates. The treatment of OSPW in bioreactors using GAC biofilms is a promising technology for the reduction of recalcitrant OSPW organic compounds.
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Kononenko, A. B., D. A. Bannikova, S. V. Britova, I. B. Pavlova, D. N. Nabiullina, and E. P. Savinova. "MONITORING OF FORMATION OF BIOFILMS BY OPPORTUNISTIC AND PATHOGENIC BACTERIA." Problems of Veterinary Sanitation, Hygiene and Ecology 1, no. 2 (2019): 174–82. http://dx.doi.org/10.36871/vet.san.hyg.ecol.201902011.
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The aim of the work is monitoring the formation of biofilms by opportunistic and pathogenic microorganisms. Materials and methods. The cultures of the genera Salmonella, Escherichia, Yersinia, Proteus, Citrobacter, Enterobacter, Prtovidenzia, Morganella, Klebsiella, Cronobacter, Pseudomonas, Bacillus, Staphylococcus were used in the work. The studied microorganisms were cultured in polystyrene 96-well plates. For this purpose, a daily culture of microorganisms was introduced into the wells with meat-peptone broth, having previously established a concentration of 104 mc / ml, and incubated for 24...96 hours at temperature of 37 °C. Then the medium with plankton cells was removed from the wells. 200 μl of filtered 0,1% crystal violet solution was poured into the wells of the plate and the plates were kept for 10...15 min at room temperature. Then dye was removed from the wells. Unbound dye was thoroughly washed with saline or distilled water. The plates were turned over on filter paper and dried. The presence and density of biomatrix (biofilm) was determined visually by the intensity of staining the surfaces of plates. Then, for the extraction of paint from the film, 200 μl of 96% ethanol was added to the wells and the optical density was measured on KFK-3KM spectrophotometer at a wavelength of 590 nm. Results of research. The results of the experiments allowed us to assert that within 48 hours of cultivation microorganisms form a mature biofilm, which can serve as a model for studying the process of biofilm formation. Biofilm of microorganisms of different taxonomic groups differs in density. In addition, even bacteria belonging to the same genus, under the same conditions, can form a biofilm, the density of which differs by 30...60%.
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Helmi, Karim, Sylvain Skraber, Christophe Gantzer, Raphaël Willame, Lucien Hoffmann, and Henry-Michel Cauchie. "Interactions of Cryptosporidium parvum, Giardia lamblia, Vaccinal Poliovirus Type 1, and Bacteriophages φX174 and MS2 with a Drinking Water Biofilm and a Wastewater Biofilm." Applied and Environmental Microbiology 74, no. 7 (February 15, 2008): 2079–88. http://dx.doi.org/10.1128/aem.02495-07.
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ABSTRACT Biofilms colonizing surfaces inside drinking water distribution networks may provide a habitat and shelter to pathogenic viruses and parasites. If released from biofilms, these pathogens may disseminate in the water distribution system and cause waterborne diseases. Our study aimed to investigate the interactions of protozoan parasites (Cryptosporidium parvum and Giardia lamblia [oo]cysts) and viruses (vaccinal poliovirus type 1, φX174, and MS2) with two contrasting biofilms. First, attachment, persistence, and detachment of the protozoan parasites and the viruses were assessed with a drinking water biofilm. This biofilm was allowed to develop inside a rotating annular reactor fed with tap water for 7 months prior to the inoculation. Our results show that viable parasites and infectious viruses attached to the drinking water biofilm within 1 h and persisted within the biofilm. Indeed, infectious viruses were detected in the drinking water biofilm up to 6 days after the inoculation, while viral genome and viable parasites were still detected at day 34, corresponding to the last day of the monitoring period. Since viral genome was detected much longer than infectious particles, our results raise the question of the significance of detecting viral genomes in biofilms. A transfer of viable parasites and viruses from the biofilm to the water phase was observed after the flow velocity was increased but also with a constant laminar flow rate. Similar results regarding parasite and virus attachment and detachment were obtained using a treated wastewater biofilm, suggesting that our observations might be extrapolated to a wide range of environmental biofilms and confirming that biofilms can be considered a potential secondary source of contamination.
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Aliyeva, Saida, James N. Petersen, Bong-Jae Park, and Nehal I. Abu-Lail. "Paenibacillus Naphthalenovorans Biofilms Interact with and Degrade Naphthalene as Observed using Various Microscopy Techniques." Journal of Environmental Science and Engineering Technology 7 (March 8, 2019): 6–15. http://dx.doi.org/10.12974/2311-8741.2019.07.02.
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The role of Paenibacillus naphthalenovorans biofilm formation in degrading a model polycyclic aromatic hydrocarbon (PAH) (naphthalene) was investigated via an array of microscopy techniques. The early stages of biofilm formation near a naphthalene crystal that was deposited on a glass coverslip were assayed qualitatively by growing the biofilms in batch bioreactors using either a rich carbon medium or a medium which contained naphthalene as a lone carbon source. Our results demonstrated that the biofilm selectively grew immediately adjacent to the edge of the PAH crystal, leading to a biofilm that facilitated the PAH degradation. Moreover, because PAH compounds are often found in capillary spaces in the subsurface, quantitative capillary-experiments were executed to evaluate the ability of P. naphthalenovorans biofilms in the degradation of a capillary-bound PAH contaminant. These capillary-experiments demonstrated that a biofilm forms at the pore’s opening, and that, when compared to a diffusion process in a liquid medium, this biofilm substantially increased the rate at which the PAH is cleared from the pore. These results provide an enhanced understanding of the means of biofilm adhesion and development in a presence of the model PAH compound investigated. Moreover, the work presented here demonstrates approaches not used before for monitoring biofilm formation.
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Pokharel, Khilasa, Bishwa Raj Dawadi, and Lok Bahadur Shrestha. "Role of Biofilm in Bacterial Infection and Antimicrobial Resistance." Journal of Nepal Medical Association 60, no. 253 (August 31, 2022): 836–40. http://dx.doi.org/10.31729/jnma.7580.
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Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. Microbial flora which produces biofilm manifests an altered growth rate and transcribes genes that provide them resistance to antimicrobial and host immune systems. Biofilms protect the invading bacteria against the immune system of the host via impaired activation of phagocytes and the complement system. Biofilm-producing isolates showed greater multidrug resistance than non-biofilm producers. Biofilm causes antibiotic resistance through processes like chromosomally encoded resistant genes, restriction of antibiotics, reduction of growth rate, and host immunity. Biofilm formation is responsible for the development of superbugs like methicillin-resistant Staphylococcus aureus, vancomycin-resistant Staphylococcus aureus, and metallo-beta-lactamase producing Pseudomonas aeruginosa. Regular monitoring of antimicrobial resistance and maintaining hygiene, especially in hospitalized patients are required to control biofilm-related infections in order to prevent antimicrobial resistance.
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CHABOWSKI, KONRAD, ADAM FELIKS JUNKA, PATRYCJA SZYMCZYK, TOMASZ PIASECKI, ANDRZEJ SIERAKOWSKI, BEATA MĄCZYŃSKA, and KAROL NITSCH. "The application of impedance microsensors for real-time analysis of Pseudomonas aeruginosa biofilm formation." Polish Journal of Microbiology 64, no. 2 (2015): 115–20. http://dx.doi.org/10.33073/pjm-2015-017.
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Biofilms formed by nosocomial pathogens represent a major threat to patients undergoing invasive procedures. As prophylaxis remains the most efficient anti-biofilm option, it is of paramount importance to develop diagnostic tools able to detect biofilm at the early stage of formation. The present study investigates the ability of impedance microsensors to detect Pseudomonas aeruginosa biofilm presence using the impedance spectroscopy method. The measured data were analyzed using Electrical Equivalent Circuit modelling (EEC). It allowed to recognize conduction and polarization phenomena on the sensors surface and in its environment. The impedance assay results, confirmed by means of electron microscopy and quantitative cultures, indicate that specific EEC parameters may be used for monitoring the development of pseudomonal biofilm.
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Valle, Jaione, Sandra Da Re, Solveig Schmid, David Skurnik, Richard D'Ari, and Jean-Marc Ghigo. "The Amino Acid Valine Is Secreted in Continuous-Flow Bacterial Biofilms." Journal of Bacteriology 190, no. 1 (November 2, 2007): 264–74. http://dx.doi.org/10.1128/jb.01405-07.
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ABSTRACT Biofilms are structured communities characterized by distinctive gene expression patterns and profound physiological changes compared to those of planktonic cultures. Here, we show that many gram-negative bacterial biofilms secrete high levels of a small-molecular-weight compound, which inhibits the growth of only Escherichia coli K-12 and a rare few other natural isolates. We demonstrate both genetically and biochemically that this molecule is the amino acid valine, and we provide evidence that valine production within biofilms results from metabolic changes occurring within high-density biofilm communities when carbon sources are not limiting. This finding identifies a natural environment in which bacteria can encounter high amounts of valine, and we propose that in-biofilm valine secretion may be the long-sought reason for widespread but unexplained valine resistance found in most enterobacteria. Our results experimentally validate the postulated production of metabolites that is characteristic of the conditions associated with some biofilm environments. The identification of such molecules may lead to new approaches for biofilm monitoring and control.
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Flemming, Hans-Curt, Thomas Griebe, and Gabriela Schaule. "Antifouling strategies in technical systems – a short review." Water Science and Technology 34, no. 5-6 (September 1, 1996): 517–24. http://dx.doi.org/10.2166/wst.1996.0591.
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The undesired deposition of microorganisms and the formation of biofilms is called “biofouling”. The consequences of biofouling for water purification, transport and storage are considerable both economically and ecologically. Countermeasures against biofouling include three steps: i) detection, ii) sanitization and iii) prevention of biofouling. The detection has to refer to surfaces. Cell counts in water water samples do not reflect the location or the extent of biofilms. Biocides display only limited value in terms of removal of biofouling layers. First, biofilm organisms are protected against biocides and tolerate 10 to 1000-fold higher concentrations. Second, water systems usually cannot be kept sterile. Thus, dead biofilms provide nutrients and suitable surfaces for further growth of cells imported with the raw water. Cleaning of a system is an integral part of sanitization and even more important than disinfection. It has to be based on a designed strategy. Efficiency control is mandatory and has to occur on representative surfaces. The prevention of biofouling is frequently achieved by continuously dosage of biocides. However, this is only possible with suitable raw waters and many failures are reported. Chlorine is still the biocide most frequently used. Concerns about effectivity and environmental protection give rise to other strategies. “Good housekeeping” is recommended as a general countermeasure. It includes frequent cleaning, efficiency control, biofilm monitoring, limitation of nutrients, maintenance of high shear forces, and a cleaning-friendly design. “Biofouling” is operationally defined and refers to biofilm development which exceeds a given “threshold of interference”. Keeping biofilm development below that threshold offers a new strategy, which considers biofouling as a biofilm reactor in the wrong place. Nutrient limitation is an option to curb biofilm development in sensitive areas. If large colonization areas are offered elsewhere than in the system to be protected, biofilms will develop there, sequestering dissolved nutrients and turning them into immobilized biomass in a place where it can be handled more easily than, e.g., inside a heat exchanger or a membrane module. Combined with effective monitoring techniques, a biocide-free antifouling-strategy can be realized.
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Heredero-Bermejo, Irene, Natalia Gómez-Casanova, Sara Quintana, Juan Soliveri, Francisco Javier de la Mata, Jorge Pérez-Serrano, Javier Sánchez-Nieves, and José Luis Copa-Patiño. "In Vitro Activity of Carbosilane Cationic Dendritic Molecules on Prevention and Treatment of Candida Albicans Biofilms." Pharmaceutics 12, no. 10 (September 25, 2020): 918. http://dx.doi.org/10.3390/pharmaceutics12100918.
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Candida spp. are one of the most common fungal pathogens. Biofilms formed by Candidaalbicans offer resistance mechanisms against most antifungal agents. Therefore, development of new molecules effective against these microorganisms, alone or in combination with antifungal drugs, is extremely necessary. In the present work, we carried out a screening process of different cationic carbosilane dendritic molecules against C. albicans. In vitro activity against biofilm formation and biofilms was tested in both Colección Española de Cultivos Tipo (CECT) 1002 and clinical C. albicans strains. Cytotoxicity was studied in human cell lines, and biofilm alterations were observed by scanning electron microscopy (SEM). Antifungal activity of the carbosilane dendritic molecules was assessed by monitoring cell viability using both established and novel cell viability assays. One out of 14 dendritic molecules tested, named BDSQ024, showed the highest activity with a minimum biofilm inhibitory concentration (MBIC) for biofilm formation and a minimum biofilm damaging concentration (MBDC) for existing biofilm of 16–32 and 16 mg/L, respectively. Synergy with amphotericin (AmB) and caspofungin (CSF) at non-cytotoxic concentrations was found. Therefore, dendritic compounds are exciting new antifungals effective at preventing Candida biofilm formation and represent a potential novel therapeutic agent for treatment of C. albicans infection in combination with existing clinical antifungals.
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Triveni, Alasthimannahalli Gangadhara, Mendem Suresh Kumar, Chavadi Manjunath, Channappa T. Shivannavar, and Subhaschandra M. Gaddad. "Biofilm formation by clinically isolated Staphylococcus Aureus from India." Journal of Infection in Developing Countries 12, no. 12 (December 31, 2018): 1062–66. http://dx.doi.org/10.3855/jidc.10671.
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Introduction: Staphylococcal biofilms are prominent cause for acute and chronic infection both in hospital and community settings across the world. Current study explores biofilm formation by Staphylococcus aureus isolates from clinical samples by different methods.
Methodology: Standard techniques used for the characterization of S.aureus. Qualitative and quantitative biofilm formation was assessed by Congo red Agar, Tube and Microtiter plate methods.
Results: A total of 188 clinical isolates of S.aureus were screened for biofilm formation and 72 (38.29%) of them were found to be biofilm producers, 34 (18.08%) strong, 38 (20.21%) moderate. The remaining 116 (61.7%) were weak/ non biofilm producers. Maximum biofilm formers were recorded in pus samples (39.06%), followed by isolates from blood (38.23%) and urine (34.61%). Statistical analysis for the formation of biofilm indicated that Microtiter plate method is the most sensitive and specific method for screening biofilm production.
Conclusions: Biofilm formation is one of the influential virulence factor in staphylococcal pathogenesis and persistence. Microtiter plate and Congo red agar remain as reliable methods for the qualitative and quantitative estimation of biofilm formation. Monitoring of biofilm formation in various etiological agents will help in determining the severity of infection.
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Reyes-Romero, D. F., O. Behrmann, G. Dame, and G. A. Urban. "Dynamic thermal sensor for biofilm monitoring." Sensors and Actuators A: Physical 213 (July 2014): 43–51. http://dx.doi.org/10.1016/j.sna.2014.03.032.
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Biggs, Catherine, and Giovanni Pavanello. "Detecting, monitoring and controlling biofilm formation." Membrane Technology 2014, no. 3 (March 2014): 9–10. http://dx.doi.org/10.1016/s0958-2118(14)70064-3.
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Nakagawa, Ryoichi, Kai Saito, Hideyuki Kanematsu, Hidekazu Miura, Masatou Ishihara, Dana M. Barry, Takeshi Kogo, et al. "Impedance Characteristics of Monolayer and Bilayer Graphene Films with Biofilm Formation and Growth." Sensors 22, no. 9 (May 6, 2022): 3548. http://dx.doi.org/10.3390/s22093548.
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Biofilms are the result of bacterial activity. When the number of bacteria (attached to materials’ surfaces) reaches a certain threshold value, then the bacteria simultaneously excrete organic polymers (EPS: extracellular polymeric substances). These sticky polymers encase and protect the bacteria. They are called biofilms and contain about 80% water. Other components of biofilm include polymeric carbon compounds such as polysaccharides and bacteria. It is well-known that biofilms cause various medical and hygiene problems. Therefore, it is important to have a sensor that can detect biofilms to solve such problems. Graphene is a single-atom-thick sheet in which carbon atoms are connected in a hexagonal shape like a honeycomb. Carbon compounds generally bond easily to graphene. Therefore, it is highly possible that graphene could serve as a sensor to monitor biofilm formation and growth. In our previous study, monolayer graphene was prepared on a glass substrate by the chemical vapor deposition (CVD) method. Its biofilm forming ability was compared with that of graphite. As a result, the CVD graphene film had the higher sensitivity for biofilm formation. However, the monolayer graphene has a mechanical disadvantage when used as a biofilm sensor. Therefore, for this new research project, we prepared bilayer graphene with high mechanical strength by using the CVD process on copper substrates. For these specimens, we measured the capacitance component of the specimens’ impedance. In addition, we have included a discussion about the possibility of applying them as future sensors for monitoring biofilm formation and growth.
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Schaefer, Susanne, Jakob Walther, Dorina Strieth, Roland Ulber, and Ulrich Bröckel. "Insights into the Development of Phototrophic Biofilms in a Bioreactor by a Combination of X-ray Microtomography and Optical Coherence Tomography." Microorganisms 9, no. 8 (August 16, 2021): 1743. http://dx.doi.org/10.3390/microorganisms9081743.
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As productive biofilms are increasingly gaining interest in research, the quantitative monitoring of biofilm formation on- or offline for the process remains a challenge. Optical coherence tomography (OCT) is a fast and often used method for scanning biofilms, but it has difficulty scanning through more dense optical materials. X-ray microtomography (μCT) can measure biofilms in most geometries but is very time-consuming. By combining both methods for the first time, the weaknesses of both methods could be compensated. The phototrophic cyanobacterium Tolypothrix distorta was cultured in a moving bed photobioreactor inside a biocarrier with a semi-enclosed geometry. An automated workflow was developed to process µCT scans of the biocarriers. This allowed quantification of biomass volume and biofilm-coverage on the biocarrier, both globally and spatially resolved. At the beginning of the cultivation, a growth limitation was detected in the outer region of the carrier, presumably due to shear stress. In the later phase, light limitations could be found inside the biocarrier. µCT data and biofilm thicknesses measured by OCT displayed good correlation. The latter could therefore be used to rapidly measure the biofilm formation in a process. The methods presented here can help gain a deeper understanding of biofilms inside a process and detect any limitations.
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Salazar, Jordi, Miquel-Àngel Amer, Antoni Turó, Nagore Castro, Marc Navarro, Sara Soto, Yaiza Gabasa, Yuly López, and Juan-Antonio Chávez. "Real-Time Detection of the Bacterial Biofilm Formation Stages Using QCM-Based Sensors." Chemosensors 11, no. 1 (January 14, 2023): 68. http://dx.doi.org/10.3390/chemosensors11010068.
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Bacterial biofilms are a major cause of harm related to medical infections and biofouling. Thus, 80% of total infections are caused by biofilm-forming microorganisms. Consequently, knowledge of biofilm formation stages is crucial to develop effective treatments to prevent their formation in medical implants, tools, and devices. For this purpose, quartz crystal microbalance (QCM) sensors are becoming a good alternative to analytical methods for the real-time monitoring of bacterial growth in liquid media culture. In a previous paper, the authors described an affordable multi-channel measurement instrument based on QCM sensors. However, in order to validate its correct operation, complementary experimental measurements based on bacterial biofilm growth were performed. In this work, the experimental measurements that allow the identification of the different biofilm formation stages are described. The results obtained are discussed.
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Kadurugamuwa, Jagath L., Lin Sin, Eddie Albert, Jun Yu, Kevin Francis, Monica DeBoer, Michael Rubin, Carole Bellinger-Kawahara, T. R. Parr,, and Pamela R. Contag. "Direct Continuous Method for Monitoring Biofilm Infection in a Mouse Model." Infection and Immunity 71, no. 2 (February 2003): 882–90. http://dx.doi.org/10.1128/iai.71.2.882-890.2003.
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ABSTRACT We have developed a rapid, continuous method for real-time monitoring of biofilms, both in vitro and in a mouse infection model, through noninvasive imaging of bioluminescent bacteria colonized on Teflon catheters. Two important biofilm-forming bacterial pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, were made bioluminescent by insertion of a complete lux operon. These bacteria produced significant bioluminescent signals for both in vitro studies and the development of an in vivo model, allowing effective real-time assessment of the physiological state of the biofilms. In vitro viable counts and light output were parallel and highly correlated (S. aureus r = 0.98; P. aeruginosa r = 0.99) and could be maintained for 10 days or longer, provided that growth medium was replenished every 12 h. In the murine model, subcutaneous implantation of the catheters (precolonized or postimplant infected) was well tolerated. An infecting dose of 10 3 to 10 5 CFU/catheter for S. aureus and P. aeruginosa resulted in a reproducible, localized infection surrounding the catheter that persisted until the termination of the experiment on day 20. Recovery of the bacteria from the catheters of infected animals showed that the bioluminescent signal corresponded to the CFU and that the lux constructs were highly stable even after many days in vivo. Since the metabolic activity of viable cells could be detected directly on the support matrix, nondestructively, and noninvasively, this method is especially appealing for the study of chronic biofilm infections and drug efficacy studies in vivo.
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Li, Qian, Rui Yong Zhang, Beate A. Krok, Mario Vera, and Wolfgang Sand. "Biofilm Formation of Sulfobacillus thermosulfidooxidans on Pyrite in the Presence of Leptospirillum ferriphilum." Advanced Materials Research 1130 (November 2015): 141–44. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.141.
Full textAbstract:
In this study, initial attachment to and biofilm formation of Sulfobacillusthermosulfidooxidans DSM 9293T on pyrite in the presence of Leptospirillumferriphilum DSM 14647T were investigated. Interactions of S.thermosulfidooxidansT and L.ferriphilumT were studied by means of monitoring attachment behavior and biofilm formation on pyrite. Our preliminary results showed that 1): Pre-established biofilms of L.ferriphilumT had effects on attachment of S. thermosulfidooxidansT to pyrite; 2): physical contact between cells of L. ferriphilumT and S. thermosulfidooxidansT on pyrite were visible 3): Pyrite leaching by cells of S. thermosulfidooxidansT was inhibited by the presence of inactive cells of L.ferriphilumT.
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Renslow, R. S., J. T. Babauta, P. D. Majors, H. S. Mehta, R. J. Ewing, T. W. Ewing, K. T. Mueller, and H. Beyenal. "A biofilm microreactor system for simultaneous electrochemical and nuclear magnetic resonance techniques." Water Science and Technology 69, no. 5 (December 26, 2013): 966–73. http://dx.doi.org/10.2166/wst.2013.802.
Full textAbstract:
Nuclear magnetic resonance (NMR) techniques are ideally suited for the study of biofilms and for probing their microenvironments because these techniques allow for noninvasive interrogation and in situ monitoring with high resolution. By combining NMR with simultaneous electrochemical techniques, it is possible to sustain and study live biofilms respiring on electrodes. Here, we describe a biofilm microreactor system, including a reusable and a disposable reactor, that allows for simultaneous electrochemical and NMR techniques (EC-NMR) at the microscale. Microreactors were designed with custom radio frequency resonator coils, which allowed for NMR measurements of biofilms growing on polarized gold electrodes. For an example application of this system we grew Geobacter sulfurreducens biofilms on electrodes. EC-NMR was used to investigate growth medium flow velocities and depth-resolved acetate concentration inside the biofilm. As a novel contribution we used Monte Carlo error analysis to estimate the standard deviations of the acetate concentration measurements. Overall, we found that the disposable EC-NMR microreactor provided a 9.7 times better signal-to-noise ratio over the reusable reactor. The EC-NMR biofilm microreactor system can ultimately be used to correlate extracellular electron transfer rates with metabolic reactions and explore extracellular electron transfer mechanisms.