Relevant bibliographies by topics / Bacterial polymers

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
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  6. Reports

Academic literature on the topic 'Bacterial polymers'

Author: Grafiati
Published: 7 February 2023

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Journal articles on the topic "Bacterial polymers"

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Secor, Patrick R., Lia A. Michaels, Anina Ratjen, Laura K. Jennings, and Pradeep K. Singh. "Entropically driven aggregation of bacteria by host polymers promotes antibiotic tolerance inPseudomonas aeruginosa." Proceedings of the National Academy of Sciences 115, no. 42 (October 1, 2018): 10780–85. http://dx.doi.org/10.1073/pnas.1806005115.

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Bacteria causing chronic infections are generally observed living in cell aggregates suspended in polymer-rich host secretions, and bacterial phenotypes induced by aggregated growth may be key factors in chronic infection pathogenesis. Bacterial aggregation is commonly thought of as a consequence of biofilm formation; however the mechanisms producing aggregation in vivo remain unclear. Here we show that polymers that are abundant at chronic infection sites cause bacteria to aggregate by the depletion aggregation mechanism, which does not require biofilm formation functions. Depletion aggregation is mediated by entropic forces between uncharged or like-charged polymers and particles (e.g., bacteria). Our experiments also indicate that depletion aggregation of bacteria induces marked antibiotic tolerance that was dependent on the SOS response, a stress response activated by genotoxic stress. These findings raise the possibility that targeting conditions that promote depletion aggregation or mechanisms of depletion-mediated tolerance could lead to new therapeutic approaches to combat chronic bacterial infections.
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van Loosdrecht, M. C. M., M. A. Pot, and J. J. Heijnen. "Importance of bacterial storage polymers in bioprocesses." Water Science and Technology 35, no. 1 (January 1, 1997): 41–47. http://dx.doi.org/10.2166/wst.1997.0008.

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In waste water treatment processes microorganisms are subjected to a feast and famine regime. For sequencing batch processes this is often even more pronounced. Based on literature reports and own research it is hypothesized that in general microorganisms respond to these feast-famine regimes by accumulating storage polymers (polyhydroxyalkanoates) when substrate is present. The storage polymers are used for growth when the external substrate is depleted. In this manner the organisms are capable to balance their growth. A general hypothesis explaining polymer formation is developed. The advantages and disadvantages of this formation of storage polymers for the operation of SBR processes is discussed.
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Carrasco-Acosta, Marina, Marta Santos-Garcia, and Pilar Garcia-Jimenez. "Marine Bacteria Associated with Colonization and Alteration of Plastic Polymers." Applied Sciences 12, no. 21 (November 1, 2022): 11093. http://dx.doi.org/10.3390/app122111093.

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The aim of this work was molecular identification of bacteria associated with marine sand at the drift line, where most plastic debris is deposited, and evaluation of the alteration of plastic polymers by them. Bacterial communities growing on plastic polymer surfaces may differentially cause surface alteration through exopolysaccharide production. This alteration can be analyzed by changes in spectra regions of colonized polymers compared to uncolonized polymers using Fourier Transform Infrared Spectroscopy (FTIR). In this study, bacteria located in sand at the drift line above sea water, where microplastics are most abundant, were isolated and identified through 16S rRNA. Six of the identified species produced exopolysaccharides, namely Bacillus thuringiensis, B. cereus, Bacillus sp. Proteus penneri, Alcaligenes faecalis and Myroides gitamensis. These bacteria species were inoculated into plates, each containing two frequently reported types of polymers at the drift line. Specifically, the two types of plastic polymers used were polypropylene and polystyrene spheres in whole and mechanically crushed states. Differences in bacterial growth were reported as inferred from weight increase of polypropylene and polystyrene spheres after 1-year long culture. Results also showed that Alcaligenes faecalis, Bacillus cereus and Proteus penneri colonized polypropylene spheres and modified spectra regions of FTIR. It is concluded that bacteria located in sand can be considered plastic-altering bacteria as changes in FTIR-spectra of polymers can be related to bioalteration.
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Deng, Shuhua, Anfu Chen, Weijia Chen, Jindi Lai, Yameng Pei, Jiahua Wen, Can Yang, et al. "Fabrication of Biodegradable and Biocompatible Functional Polymers for Anti-Infection and Augmenting Wound Repair." Polymers 15, no. 1 (December 28, 2022): 120. http://dx.doi.org/10.3390/polym15010120.

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The problem of bacteria-induced infections threatens the lives of many patients. Meanwhile, the misuse of antibiotics has led to a significant increase in bacterial resistance. There are two main ways to alleviate the issue: one is to introduce antimicrobial agents to medical devices to get local drug releasing and alleviating systemic toxicity and resistance, and the other is to develop new antimicrobial methods to kill bacteria. New antimicrobial methods include cationic polymers, metal ions, hydrophobic structures to prevent bacterial adhesion, photothermal sterilization, new biocides, etc. Biodegradable biocompatible synthetic polymers have been widely used in the medical field. They are often used in tissue engineering scaffolds as well as wound dressings, where bacterial infections in these medical devices can be serious or even fatal. However, such materials usually do not have inherent antimicrobial properties. They can be used as carriers for drug delivery or compounded with other antimicrobial materials to achieve antimicrobial effects. This review focuses on the antimicrobial behavior, preparation methods, and biocompatibility testing of biodegradable biocompatible synthetic polymers. Degradable biocompatible natural polymers with antimicrobial properties are also briefly described. Finally, the medical applications of these polymeric materials are presented.
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Ringenberg, L., A. Winkel, O. Kufelt, P. Behrens, M. Stiesch, and W. Heuer. "The Effectiveness of Poly-(4-vinyl-N-hexylpyridiniumbromide) as an Antibacterial Implant Coating: AnIn VitroStudy." International Journal of Dentistry 2011 (2011): 1–11. http://dx.doi.org/10.1155/2011/859140.

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The clinical success of osseointegrated dental implants depends on the strong attachment of the surrounding hard and soft tissues. Bacterial adhesion on implant surfaces can cause inflammatory reactions and may influence healing and long-term success of dental implants. Promising implant coatings should minimize bacterial adhesion, but allow epithelial and connective tissue attachment. Therefore, the present study has examined the bioactive effect of poly-(4-vinyl-N-hexylpyridiniumbromide) regarding typical oral bacteria as well as cytotoxicitiy to human cells considering different methods of connecting polymers to silicate-containing surfaces. The results revealed that the application of putative antibacterial and biocompatible polymer in coating strategies is affected by a variety of parameters. Published findings regarding reduced bacterial adhesion could not be verified using oral pathogens whereas hexylated polymers seem problematic for strong adhesion of soft tissue. Concerning innovative coatings for dental implants basic aspects (surface roughness, thickness, alkylation, combination with other polymers) have to be considered in further investigations.
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Fujiwara, Natsumi, Hiromichi Yumoto, Koji Miyamoto, Katsuhiko Hirota, Hiromi Nakae, Saya Tanaka, Keiji Murakami, Yasusei Kudo, Kazumi Ozaki, and Yoichiro Miyake. "2-Methacryloyloxyethyl phosphorylcholine (MPC)-polymer suppresses an increase of oral bacteria: a single-blind, crossover clinical trial." Clinical Oral Investigations 23, no. 2 (May 16, 2018): 739–46. http://dx.doi.org/10.1007/s00784-018-2490-2.

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Abstract Objectives The biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC)-polymers, which mimic a biomembrane, reduce protein adsorption and bacterial adhesion and inhibit cell attachment. The aim of this study is to clarify whether MPC-polymer can suppress the bacterial adherence in oral cavity by a crossover design. We also investigated the number of Fusobacterium nucleatum, which is the key bacterium forming dental plaque, in clinical samples. Materials and methods This study was a randomized, placebo-controlled, single-blind, crossover study, with two treatment periods separated by a 2-week washout period. We conducted clinical trial with 20 healthy subjects to evaluate the effect of 5% MPC-polymer mouthwash after 5 h on oral microflora. PBS was used as a control. The bacterial number in the gargling sample before and after intervention was counted by an electronic bacterial counter and a culture method. DNA amounts of total bacteria and F. nucleatum were examined by q-PCR. Results The numbers of total bacteria and oral streptcocci after 5 h of 5% MPC-polymer treatment significantly decreased, compared to the control group. Moreover, the DNA amounts of total bacteria and F. nucleatum significantly decreased by 5% MPC-polymer mouthwash. Conclusions We suggest that MPC-polymer coating in the oral cavity may suppress the oral bacterial adherence. Clinical relevance MPC-polymer can be a potent compound for the control of oral microflora to prevent oral infection.
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Tyagi, Anju, and Abhijit Mishra. "Methacrylamide based antibiotic polymers with no detectable bacterial resistance." Soft Matter 17, no. 12 (2021): 3404–16. http://dx.doi.org/10.1039/d0sm02176h.

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We report the synthesis of methacrylamide-based polymers with high antibacterial efficacy and selectivity. The polymers disrupt bacterial membranes and are less susceptible to the development of resistance in bacteria.
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Maruthapandi, Moorthy, Arumugam Saravanan, Akanksha Gupta, John H. T. Luong, and Aharon Gedanken. "Antimicrobial Activities of Conducting Polymers and Their Composites." Macromol 2, no. 1 (February 9, 2022): 78–99. http://dx.doi.org/10.3390/macromol2010005.

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Conducting polymers, mainly polyaniline (PANI) and polypyrrole (PPY) with positive charges bind to the negatively charged bacterial membrane to interfere with bacterial activities. After this initial electrostatic adherence, the conducting polymers might partially penetrate the bacterial membrane and interact with other intracellular biomolecules. Conducting polymers can form polymer composites with metal, metal oxides, and nanoscale carbon materials as a new class of antimicrobial agents with enhanced antimicrobial properties. The accumulation of elevated oxygen reactive species (ROS) from composites of polymers-metal nanoparticles has harmful effects and induces cell death. Among such ROS, the hydroxyl radical with one unpaired electron in the structure is most effective as it can oxidize any bacterial biomolecules, leading to cell death. Future endeavors should focus on the combination of conducting polymers and their composites with antibiotics, small peptides, and natural molecules with antimicrobial properties. Such arsenals with low cytotoxicity are expected to eradicate the ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.
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Sharma, Hemlata, Jyoti Pal, and Deepesh Kumar Neelam. "Bacterial Extracellular Polymers: A Review." Journal of Pure and Applied Microbiology 15, no. 3 (July 17, 2021): 1072–82. http://dx.doi.org/10.22207/jpam.15.3.28.

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Prokaryotic microbial cells especially bacteria are highly emphases for their exopolysaccharides (EPS) production. EPS are the higher molecular weight natural extracellular compounds observe at the surface of the bacterial cells. Nowadays bacterial EPS represent rapidly emerging as new and industrially important biomaterials because it having tremendous physical and chemical properties with novel functionality. Due to its industrial demand as well as research studies the different extraction processes have been discovered to remove the EPS from the microbial biofilm. The novelties of EPS are also based on the microbial habitat conditions such as higher temperature, lower temperature, acidic, alkaliphilic, saline, etc. Based on its chemical structure they can be homopolysaccharide or heteropolysaccharide. EPSs have a wide range of applications in various industries such as food, textile, pharmaceutical, heavy metal recovery, agriculture, etc. So, this review focus on the understanding of the structure, different extraction processes, biosynthesis and genetic engineering of EPS as well as their desirable biotechnological applications.
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TAKAI, Mitsuo, and Tomoki ERATA. "Natural Polymers. Bacterial Cellulose." Kobunshi 47, no. 6 (1998): 382–85. http://dx.doi.org/10.1295/kobunshi.47.382.

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Dissertations / Theses on the topic "Bacterial polymers"

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Adebayo, Olajumoke O. "Evaluation of bacterial polymers as protective agents for sensitive probiotic bacteria." Thesis, University of Wolverhampton, 2018. http://hdl.handle.net/2436/621096.

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Probiotics are live microorganisms which when administered in adequate amounts confer one or more health benefits on the host. Different processing conditions, the acidic condition of the stomach and exposure to hydrolytic enzymes affect the viability and efficacy of probiotic organisms. This study investigated the protective effects of two biopolymers poly-gamma-glutamic acid (γ-PGA) and bacterial cellulose (BC) on probiotics during freeze drying and during exposure to simulated intestinal juices and bile salts. The antibacterial property of Bifidobacterium strains was also investigated against four pathogenic bacteria. γ-PGA, a naturally occurring biopolymer was produced by two bacteria (Bacillus subtilis ATCC 15245 and B. licheniformis ATCC 9945a) in GS and E media, γ-PGA yields of about 14.11g/l were achieved in shake flasks and molecular weight of up to 1620 k Da was recorded, γ-PGA production was scaled up in a fermenter with B. subtilis using GS medium. BC, an edible biopolymer was produced by Gluconacetobacter xylinus ATCC 23770 in HS medium and a modified HS (MHS) medium. A yield of about 1.37g/l was recorded and BC production with MHS medium was used for probiotic application. B. longum NCIMB 8809 B. breve NCIMB 8807 and B. animalis NCIMB 702716 showed the best antimicrobial properties against the investigated pathogens. Survival of Bifidobacterium strains was improved when protected with powdered BC (PBC) although γ-PGA offered better protection than PBC. Viability of B. longum NCIMB 8809, B. breve NCIMB 8807 and B. animalis NCIMB 702716 in simulated gastric juice (SGJ) and simulated intestinal juice with bile salts was improved when protected with 5% γ-PGA and 5% γ-PGA+PBC with a reduction of < 1 Log CFU/ml while a reduction of ≤2 Log CFU/ml was recorded in PBC protected cells. Protecting Bifidobacterium strains with γ-PGA, PBC or a novel γ-PGA + PBC combination is a promising method to deliver probiotic bacteria to the target site in order to confer their health benefits on the host.
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Magennis, Eugene Peter. "Bacterial auto-nemesis : templating polymers for cell sequestration." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/14503/.

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The detection and control of microorganisms such as bacteria is important in a wide range of industries and clinical settings. Detection, binding and removal of such pathogenic contaminants can be achieved through judicious consideration of the targets which are available at or in the bacterial cell. Polymers have the ability to present a number of binding ligands for cell targeting on one macromolecule and so avidity of interaction can be greatly increased. The goal of the project was to test whether polymers generated with bacteria in situ would have their composition significantly altered to determine if a templating process was occurring. It was also anticipated that the templated polymers would have better re-binding properties than those produced in the absence of bacteria. A series of chemical functionalities were analysed for their binding properties to bacteria. The functionalities were chosen with consideration to the cell surface characteristics. Further to identification of the most binding and least binding functionalities the polymers were tested for their cytotoxicity against bacteria and human epithelial cells. Concentration ranges were determined which could facilitate bacterial binding and templating yet minimise the lethality of the processes. Templated polymers of the bacteria were generated using a novel method of atom transfer radical polymerisation (ATRP) which we have termed bacterial activated atom transfer radical polymerisation (b-ATRP). This polymerisation method has maximised the potential for templating processes to occur during the polymerisation. Templated polymers differed in both their composition and their binding behaviour to non-templated polymers. The bacterial organic reduction process has also been demonstrated to have greater scope for use within the organic chemistry field as demonstrated by the use of this system to enable in "click-chemistry" via the reduction of copper.
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Freebairn, David Alexander. "Electrical control of bacterial adherence to conducting polymers." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680117.

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In this thesis, low direct currents (DC) have been shown to successfully reduce bacterial adherence to conducting polymers in unique electrically modified flow devices without the aid of an antimicrobial agent. However, alternating currents (AC) and radio-frequency currents (RF) were not found to be effective. The design and manufacture of these new DC and RF flow devices has been comprehensively documented within, accompanied by relevant standard operating procedures and experimental designs. Additionally, the thesis includes a review of seminal bioelectric literature and discusses the potential for exciting future developments in this multidisciplinary field of research. These findings are ultimately intended to facilitate the design of new indwelling medical devices (IMDs) as well as electrically sterilized polymer surfaces for a wide range of far-reaching applications in industries where bacterial biofilms proliferate
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Kajornatiyudh, Sittiporn. "Bacterial extracellular polymers and flocculation of activated sludges." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/52313.

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The extracellular polymers produced by bacteria play an important role in bacterial aggregation or bacterial flocculation in secondary waste treatment. The mechanisms responsible for this floc formation are thought to be polymer induced adsorption and interparticle bridging among bacterial cells or between bacterial cells and inorganic colloids. The efficiency of the processes following flocculation in the treatment line such as sedimentation, sludge thickening, and sludge dewatering depends on the extent of this bacterial flocculation. In this research, sludge samples from under various substrate conditions were examined for type, molecular weight, physical characteristics„ and quantity of extracellular polymers so that the general characteristics of the various polymers could be established. An attempt was made to determine if a relationship exists between the state of bacterial aggregation and the polymer characteristics. This research also investigated the sludge physical properties. The effect of various parameters such as pH, divalent cation (mixture and concentration), and mixing (period and intensity) on dewatering properties were studied. A major goal of this study was to develop a flocculation model for activated sludge. This model could be used to determine if plants can increase the efficiency of waste treatment and sludge thickening and sludge dewatering processes.
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Atabek, Arzu. "Investigating bacterial outer membrane polymers and bacterial interactions with organic molecules using atomic force microscopy." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-082206-162049/.

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Wendels, Sophie. "Synthesis and elaboration of new biobased hemostatic adhesives from bacterial polymers." Thesis, Strasbourg, 2021. http://www.theses.fr/2021STRAE006.

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Les polyuréthanes (PU) sont une des principales familles de polymères démontrant des propriétés variées pour de multiples applications. Ces propriétés leurs ont permis d’être utilisés dans le domaine du biomédical depuis des décennies. Avec le développement actuel de nombreuses molécules issues de la biomasse, les possibilités d’innovation dans les matériaux biosourcés sont multiples. Aujourd’hui, des PUs aux propriétés avancées sont développés. Cependant, il y a toujours un manque de solutions plus respectueuses de l’environnement et efficaces comme adhésifs hémostatiques. Ainsi, ce travail a porté sur l’élaboration d’une nouvelle série d’adhésifs biosourcés PU à partir de différentes biomasses telles que les polymères bactériens et les huiles végétales, mais pas seulement. Plusieurs séries d’adhésifs ont été préparées et caractérisées, et proposent une large gamme de propriétés spécifiques aux adhésifs tels que la viscosité, le temps de réaction, l’adhésion tissulaire et l’éxothermie. De plus, des systèmes correspondant à l’état chimique final des adhésifs au contact des tissus ont été préparés et caractérisés. Selon la formulation, les propriétés physico-chimiques, thermiques et mécaniques peuvent être adaptées à différents tissus. La cytotoxicité et la dégradation, qui sont des paramètres clés pour une utilisation dans le biomédical, ont également été évaluées
Polyurethanes (PUs) are a major family of polymers used in a large range of fields. Moreover, they display a wide spectrum of physico-chemical, mechanical and structural properties. In this regard, they have shown suitable for biomedical applications and are used in this domain since decades. The current variety of biomass available has extended the diversity of starting materials for the elaboration of new biobased macromolecular architectures, allowing the development of biobased PUs with advanced properties. Nowadays, there is a need for more environmentally friendly and effective solutions for tissue adhesive purposes. In this frame, new renewably sourced PU-based hemostatic adhesives have been successfully designed. Chosen biomasses were mainly from bacterial ressources and vegetable oils, but not only. Many different adhesive formulations were obtained and characterized, and the developed adhesives offer a broad range of specific properties such as viscosity, curing time, tissue adhesion and exothermy. PUs, corresponding to the final adhesives chemical state in contact with the tissue, were also prepared and studied. They exhibited tailored physico-chemical, thermal and mechanical properties, close to diverse tissue native mechanical properties. Cytotoxicity and degradation, which are key parameters for biomedical applications, were also investigated
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Boltz, Joshua. "The Kinetics of Particulate Substrate Utilization by Bacterial Films." ScholarWorks@UNO, 2005. http://scholarworks.uno.edu/td/254.

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There is a need to develop a mathematical expression capable of describing the removal of particulate chemical oxygen demand (PCOD) from wastewaters in biological film systems. In this context, organic particles that are maintained in suspension (i.e., not removed during normal settling) are the focus of experimentation, modeling, and discussion. The goal of this research project is to study the kinetics of PCOD removal from wastewaters by bacterial films, or biofilms. To achieve this objective, a bench-scale rotating disc biofilm reactor (RDBR) was operated using methanol (dissolved substrate), Min-U-Sil 10 (inorganic particulates), and Maizena corn starch (organic particulates) dissolved/suspended in the influent stream. The effect of the ratio of biofilm area to volumetric flow rate passing through the RDBR on the concentration of substrate remaining in the final effluent was determined, and the kinetic relationship was established for both dissolved substrate and particle removal. Exocellular polymeric substances (EPS) were extracted and quantified in order to explain the role of biological flocculation, or bioflocculation, in particulate removal. In the literature, Fick's first law and zero-order kinetics have described the diffusion and biochemical reaction of soluble substrate within the bacterial film matrix (when completely penetrated), respectively. The present study confirms this kinetic behavior for various influent methanol concentrations. On the other hand, the removal of particulates, organic and inorganic, adheres to first-order reaction kinetics. These findings, coupled with the identification of EPS, attribute bioflocculation as the primary removal mechanism of particulates. A mass balance on the biofilm reactor allowed for the development of a comprehensive rate expression for substrate consumption by biofilms when both dissolved and particulate substrates are available. Total chemical oxygen demand (TCOD) is comprised of dissolved chemical oxygen demand (DCOD) and PCOD, each of which can be readily determined through laboratory analysis. An equation was developed that accurately describes the disappearance of TCOD by the bioflocculation of PCOD and consumption of DCOD in the bench scale RDBR.
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Zakrisson, Johan. "The mechanics of adhesion polymers and their role in bacterial attachment." Doctoral thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-109524.

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Bacterial resistance to antibiotics is increasing at a high rate in both developing and developed countries. To circumvent the problem of drug-resistant bacterial pathogens, we need to develop new effective methods, substances, and materials that can disarm and prevent them from causing infections. However, to do this we first need to find new possible targets in bacteria to approach and novel strategies to apply.Escherichia coli (E. coli) bacteria is a normal member of the intestinal microflora of humans and mammals, but frequently cause diverse intestinal and external diseases by means of virulence factors, which leads to hundreds of million sick people each year with a high mortality rate. An E. coli bacterial infection starts with adhesion to a host cell using cell surface expressed adhesion polymers, called adhesion pili. Depending on the local environment different types of pili are expressed by the bacteria. For example, bacteria found in the gastrointestinal tract commonly express different pili in comparison to those found in the urinary tract and respiratory tract. These pili, which are vital for bacterial adhesion, thereby serve as a new possible approach in the fight against bacterial infections by targeting and disabling these structures using novel chemicals. However, in order to develop such chemicals, better understanding of these pili is needed.Optical tweezers (OT) can measure and apply forces up to a few hundred pN with sub-pN force resolution and have shown to be an excellent tool for investigating mechanical properties of adhesion pili. It has been found that pili expressed by E. coli have a unique and complex force-extension response that is assumed to be important for the ability of bacteria to initiate and maintain attachment to the host cells. However, their mechanical functions and the advantage of specific mechanical functions, especially in the initial attachment process, have not yet been fully understood.In this work, a detailed description of the pili mechanics and their role during cell adhesion is presented. By using results from optical tweezers force spectroscopy experiments in combination with physical modeling and numerical simulations, we investigated how pili can act as “shock absorbers” through uncoiling and thereby lower the fluid force acting on a bacterium. Our result demonstrate that the dynamic uncoiling capability of the helical part of the adhesion pili modulate the force to fit the optimal lifetime of its adhesin (the protein that binds to the receptor on the host cell), ensuring a high survival probability of the bond.iiiSince the attachment process is in proximity of a surface we also investigated the influence of tether properties and the importance of different surface corrections and additional force components to the Stokes drag force during simulations. The investigation showed that the surface corrections to the Stokes drag force and the Basset force cannot be neglected when simulating survival probability of a bond, since that can overestimate the probability by more than an order of magnitude.Finally, a theoretical and experimental framework for two separate methods was developed. The first method can detect the presence of pili on single cells using optical tweezers. We verified the method using silica microspheres coated with a polymer brush and E. coli bacteria expressing; no pili, P pili, and type 1 pili, respectively. The second method was based on digital holography microscopy. Using the diffraction of semi-transparent object such as red blood cells, we showed that this method can reconstruct the axial position and detect morphological changes of cells.
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Parikh, Sanjai Jagadeep. "A Spectroscopic Study of Bacterial Polymers Mediating Cell Adhesion and Mineral Transformations." Diss., Tucson, Ariz. : University of Arizona, 2006. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1456%5F1%5Fm.pdf&type=application/pdf.

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Flo, Trude Helen. "Receptors involved in cell activation by defined uronic acid polymers and bacterial components." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Medicine, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-39.

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PAPER 1

In the first paper we show that reducing the average molecular weight from ~350 kDa to <6kDa by acid hydrolysis diminished the cell-stimulating activity of poly-M, measured as TNFproduction from human monocytes. However, the activity of the resulting oligomers (M-blocks) was greatly enhanced when covalently attached to particles (plastic beads or biodegradable albumin particles). Similar results were obtained with detoxified/deacylated LPS (DLPS) and glucuronic acid polymers (C6OXY), but not with G-blocks that by themselves are not active. These results suggest that the supramolecular structure affects the potency of polysaccharide stimuli, and that M-blocks attached to biodegradable albumin particles could possibly be exploited as an immunostimulant for protection against various diseases.

PAPER 2

In paper 2, according to the reviewers suggestion, the designation M-polymers of different molecular size was used in place of poly-M (~350 kDa) and M-blocks (~3 kDa). In this study we demonstrated that M-blocks and DLPS attached to particles engaged different receptors than soluble poly-M and DLPS in activation of monocytes. By using blocking mAbs to CD14, CD11b and CD18, we found that particulate stimuli employed the β2- integrin CD11b/CD18 in addition to the shared CD14 for signaling TNF-production. Moreover, whereas poly-M only bound to CD14-expressing CHO-cells, M-particles preferentially bound to CHO-cells expressing β2-integrins. However, the DLPS- and M-particles failed to activate NF-κB-translocation in CHO-cells co-transfected with CD14 and β2-integrins, suggesting that additional molecules are required for activation of CHO-cells. The major conclusion drawn from this work is that the supramolecular structure, in addition to influence the potency, affects the cellular receptor engagement by carbohydrates like poly-M and DLPS. This points to the importance of comparing the mechanisms involved in activation of immune cells by soluble bacterial components and whole bacteria to achieve a better understanding of inflammatory diseases like sepsis.

PAPER 3

Poly-M activates cells in a CD14-dependent manner, but CD14 is linked to the membrane with a GPI-anchor and mediates activation by interaction with other, signal-transducing molecules, like the TLRs. By using blocking mAbs to TLR2 (generated in our lab, paper 5) and TLR4, we found that both receptors were involved in mediating TNF-production from human monocytes in response to poly-M. Furthermore, TLR4 mutant (C3H/HeJ) and knockout (TLR4-/-) murine macrophages were completely non-responsive to poly-M, whereas TLR2-deficient macrophages showed reduced TNF-responses. These findings indicate that CD14, TLR2 and TLR4 on primary cells all participate in cytokine-induction by poly-M, and that TLR4 may be necessary for activation.

PAPER 4

In addition to CD14, β2-integrins have been implicated in LPS-induced cellular activation, and in this study we compared the involvement of CD14 and β2-integrins in TNF-production and NF-κB-activation induced by LPS and GBS cell wall fragments. With blocking mAbs to CD14 and CD18 we found that LPS and GBS cell walls shared CD14, but in addition the cell walls employed CD11/CD18 in mediating TNF-production from human monocytes. Both stimuli specifically induced NF-κB-translocation in CD14-transfected CHO-cells, but only LPS could activate cells transfected with CD11/CD18. The lack of response to GBS cell walls in CD11/CD18-transfected CHO-cells indicated that the cell walls need CD14 for cell activation. Further in paper 4 we demonstrate the ability of GBS cell walls to activate LPS-hyporesponsiv C3H/HeJ mouse macrophages, suggesting that LPS and GBS cell walls employ different receptors/signaling mechanisms in murine macrophages.

PAPER 5

When it was discovered that human TLR2 and TLR4 are involved in microbial recognition, we started to generate a mouse mAb to human TLR2, and in paper 5 we report the production and characterization of the mAb TL2.1. We subsequently used this mAb to evaluate the role of TLR2 in mediating activation by heat-killed GBS and L monocytogenes. L. monocytogenes, but not GBS, activated TLR2-transfected CHO-cells to IL-6-production, and the response was inhibited by TL2.1. A CD14 mAb and TL2.1 both inhibited TNF-production from monocytes induced by L. monocytogenes, but neither mAb affected the TNF-response triggered by GBS. Our results suggest that CD14 and TLR2 are engaged in cell activation by L. monocytogenes, but that neither receptor seem to be involved in activation by GBS. This study was the first to show that human TLR2 can discriminate between two G+ bacteria.

PAPER 6

In paper 6 we report the generation of a new TLR2 mAb, TL2.3, that stained with the same specificity as TL2.1 (anti-TLR2, paper 5). We used these mAbs to investigate the expression of TLR2 protein in human cells. We found that TLR2 was highly expressed in blood monocytes, less in granulocytes, and not present in lymphocytes. The protein level was measured on quiescent and activated cells by extra- and intracellular flow cytometry, and by immunoprecipitation of TLR2 from metabolic S35-labeled cells. Surprisingly, TLR2 protein was detected in activated B-cells located in lymphoid germinal centers, indicating that subsets of lymphocytes may express TLR2. We further show that TLR2 protein was differentially regulated on monocytes and granulocytes after exposure to LPS, pro- or anti-inflammatory cytokines. However, we could not correlate the regulation of TLR2 to cellular responses, as for instance the three anti-inflammatory cytokines TGFβ, IL-4 and IL-10 all inhibited lipopeptideinduced TNF-production, but either did not affect, reduced, or increased the level of surface TLR2, respectively. Thus, the biological significance of TLR2-regulation remains to be found.

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Books on the topic "Bacterial polymers"

1

International Symposium on Bacterial Polyhydroxyalkanoates (5th 1996 Davos, Switzerland). 1996 International Symposium on Bacterial Polyhydroxyalkanoates. Ottawa: NRC Research Press, 1997.

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Ross, Shari. The importance of bacterial roles in the degradation of phaeocystis polymers. Bellingham, WA: Huxley College of Environmental Studies, Western Washington University, 2000.

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Speicherung von Polyhydroxyfettsäuren in schwefelfreien Purpurbakterien: Charakterisierung der Polymere und der PHB-Synthese-Gene sowie Beziehung zur Photoproduktion von Wasserstoff. Göttingen: Unitext, 1992.

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D, Knudsen Walter, and Bruns Sam S, eds. Bacterial DNA, DNA polymerase, and DNA helicases. Hauppauge, NY: Nova Science, 2009.

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5

Turner, Helen Louise. The use of polymerase chain reaction in determining the mechanism of bacterial resistence to fluoroquinolone antibiotics. Birmingham: University of Birmingham, 1995.

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Vekshin, N. L. Biophysics of DNA-antibiotic complexes. Hauppauge, N.Y: Nova Science Publishers, 2010.

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L, Hershberger Charles, Queener Stephen W, Hegeman George, American Society for Microbiology, and ASM Conference on the Genetics and Molecular Biology of Industrial Microorganisms (4th : 1988 : Bloomington, Ind.), eds. Genetics and molecular biology of industrial microorganisms. Washington, D.C: American Society for Microbiology, 1989.

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Amos, Linda A., and Jan Löwe. Prokaryotic Cytoskeletons: Filamentous Protein Polymers Active in the Cytoplasm of Bacterial and Archaeal Cells. Springer, 2017.

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Amos, Linda A., and Jan Löwe. Prokaryotic Cytoskeletons: Filamentous Protein Polymers Active in the Cytoplasm of Bacterial and Archaeal Cells. Springer, 2018.

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Microbial extracellular polymeric substances: Characterization, structure, and function. Berlin: Springer, 1999.

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Book chapters on the topic "Bacterial polymers"

1

Gooch, Jan W. "Bacterial Corrosion." In Encyclopedic Dictionary of Polymers, 62. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_975.

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Gooch, Jan W. "Bacterial Conjunctivitis." In Encyclopedic Dictionary of Polymers, 877. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13219.

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Gooch, Jan W. "Bacterial Endocarditis." In Encyclopedic Dictionary of Polymers, 877. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13220.

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Gooch, Jan W. "Bacterial Enteritis." In Encyclopedic Dictionary of Polymers, 877. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13221.

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Gooch, Jan W. "Bacterial Lawn." In Encyclopedic Dictionary of Polymers, 877. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13222.

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Gooch, Jan W. "Bacterial Meningitis." In Encyclopedic Dictionary of Polymers, 877. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13223.

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Marković, Zoran M., and Biljana M. Todorović Marković. "Novel Antimicrobial Strategies to Combat Biomaterial Infections." In Urinary Stents, 305–13. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04484-7_24.

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AbstractBacteria are present in nature everywhere and the combat with them has the major priority especially in various industrial settings (i.e. food industry) or medical devices. It was established earlier that most of bacteria found in nature exist in the form of biofilms (attached to surface of different objects and not as free floating organisms).There are several possible strategies to reduce or prevent bacterial infections among different populations: patients and medical staff. One of the alternative strategies independent of human labor, is to produce antibacterial coatings to reduce or eliminate bacteria colonization on surfaces by leaching of biocides, antibacterial surfaces with deposited metals such as copper, silver or gold, formation of superhydrophobic surfaces and surfaces encapsulated by photoactive nanoparticles.A new light triggered strategies to combat bacterial infections and possible usage of photoactive polymers for these purposes. Photoactive antibacterial polymers are highly promising solution for novel medical devices. To enable their wise usage for the treatment of urinary infections some changes must be made. For example, the effectiveness of photoactive polymers inside human body can be increased by incorporation of micron sized electronic devices (light emitting diode, light detector, pH sensor, radio frequent device) into polymer matrices.
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Rodríguez-Hernández, Juan. "Bacterial Infections: Few Concepts." In Polymers against Microorganisms, 13–37. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-47961-3_2.

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Bhavaniramya, Sundaresan, Selvaraju Vishnupriya, and Dharmar Baskaran. "Significance of Bacterial Polyhydroxyalkanoates in Rhizosphere." In Microbial Polymers, 235–49. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0045-6_11.

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Pa’e, N., I. I. Muhamad, Z. Hashim, and A. H. M. Yusof. "Bacterial Cellulose Nanocomposites." In Bio-based Polymers and Nanocomposites, 87–105. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05825-8_5.

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Conference papers on the topic "Bacterial polymers"

1

Sano, Michael B., Rafael V. Davalos, and Paul Gatenholm. "Dielectrophoretic Microweaving: Biofabrication of Aligned Bacterial Nanocellulose for Regenerative Medicine." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206787.

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The use of natural and synthetic polymers as scaffolding material for regenerative medicine is far from clinical translation for most tissue applications. This is due primarily to lack of manufacturing control over mechanical properties and 3D architecture which promote cell attachment and proliferation. Cellulose, a natural polymer produced by the majority of plants, can be assembled into nanofibrils by bacteria. The advantage of bacterial cellulose is that it has unique biocompatibility, mechanical integrity, hydroexpansivity, and is stable under a wide range of conditions [1]. It is thus ideal as a scaffolding material on which to seed cells for regenerative medicine applications. The bacteria Acetobacter Xylinum produces nanoscale cellulose ribbons at an average rate of 2μm/min [2].
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Kuznetsov, Ivan A., Warren Jasper, Srinivasan Rasipuram, Andrey V. Kuznetsov, Alan Brown, and Alexei V. Saveliev. "Development of Plasma Textile for Nanoparticle Filtration and Bacterial Deactivation." In ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icnmm2012-73019.

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A novel woven textile material capable of generating stable low temperature plasma was created. This resulted in enhancing the capture efficiency of nanoparticles when the material was used as a filter as well as exhibiting anti-bacterial properties. The primary supposition of the study is that a micro-plasma array can be embedded into a textile fabric to induce a plasma sheath that filters and deactivates bacterial pathogens coming into contact with the fabric. The work proceeded through a series of steps: (1) determining the optimal type of plasma discharge; (2) finding the ideal wire electrode material, radii and placement to achieve stable uniform generation of non-thermal plasmas; (3) modeling the electric field surrounding the electrodes to evaluate the impact of an insulating textile on the electrode system; (4) testing various polymers and developing a plasma textile based on electrode geometries found in experimentation; (5) measuring the filtration efficiencies of the plasmas using a differential mobility and a condensation particle counter; and (6) testing the textile fabric’s ability to deactivate bacteria. The work confirmed the existence of sustainable, uniform plasma on the surface of the developed fabric capable of capturing over 98% of bacteria-sized particles and deactivating tested bacteria.
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Ravndal, Kristin T., and Roald Kommedal. "Modelling particle degradation and intermediate dynamics in a dispersed activated sludge microcosm." In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192002.

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Municipal wastewater consists of a large fraction of particulate organic matter. During biological wastewater treatment these particles undergo extracellular depolymerisation before products are taken up by bacteria (MW < 0.6 kDa). Particle degradation and intermediate formation dynamics is important in process analysis of wastewater treatment as the transport regime differ. This work aims to develop a model for particle degradation that includes intermediate dynamics as observed in experimental work. A model for particle degradation including intermediate dynamics, bacterial growth and endogenous respiration is proposed. Particle hydrolysis was modelled using the particle breakup model. Depolymerisation products were separated into five different size groups: colloids; high, medium and low molecular weight (HMW, MMW and LMW) polymers; and one fraction for oligomers and monomers (SB). Depolymerisation of colloids, HMW and MMW polymers was modelled using first order kinetics. LMW polymer degradation was modelled using Michaelis-Menten kinetics, while growth was based on traditional Monod kinetics and endogenous respiration followed ASM3. The proposed model was implemented in AQUASIM for a batch reactor system, and parameter estimation by LSE fitting to experimental data on particulate starch degradation over 117 days in a dispersed biomass microcosm was performed. Validation of the model against experimental data gave a very good fit to the PBM. The intermediate dynamics seen in the experimental data was also qualitatively demonstrated by the model, with accumulation of HMW, MMW and LMW polymers in the bulk liquid. However, the accumulation of monomers and oligomers in the bulk liquid could not be reproduced in the suspended growth model proposed. Hence, a structured biomass model (biofilm) is suggested for future work.
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Derme, Tiziano, Daniela Mitterberger, and Umberto Di Tanna. "Growth Based Fabrication Techniques for Bacterial Cellulose: Three-Dimensional Grown Membranes and Scaffolding Design for Biological Polymers." In ACADIA 2016: Post-Human Frontiers. ACADIA, 2016. http://dx.doi.org/10.52842/conf.acadia.2016.488.

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Derme, Tiziano, Daniela Mitterberger, and Umberto Di Tanna. "Growth Based Fabrication Techniques for Bacterial Cellulose: Three-Dimensional Grown Membranes and Scaffolding Design for Biological Polymers." In ACADIA 2016: Post-Human Frontiers. ACADIA, 2016. http://dx.doi.org/10.52842/conf.acadia.2016.488.

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Bhaduri, S., S. K. Mitra, and A. Kumar. "Understanding Biofilm Growth Dynamics Within a Stagnant Culture of Sporosarcina Pasteurii." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36778.

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Biofilms are bacterial colonies that form at interfaces, where bacteria are encased in extracellular polymeric substances (EPS). Biofilms are ubiquitous in both artificial systems and our environment. Here we focus on understanding biofilm growth within a stagnant pool of confined diluted culture of the bacteria. Sporosarcina pasteurii is taken as the model bacterium for this study. The motivation behind the choice of this organism stems from the fact that S. Pasteurii has the unique ability to precipitate calcite inside the host media which has tremendous applications in reservoir and restoration engineering. As the biofilm evolves with time inside the confinement, the dynamics of transport is recorded continuously by an optical microscope and the data processed digitally to gain valuable insights into the bio-physical aspects of the system.
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Billings, Christopher, Changjie Cai, and Yingtao Liu. "Investigation of 3D Printed Antibacterial Nanocomposites for Improved Public Health." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-72092.

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Abstract Bacterial infections have been recognized as a critical challenge to public health, resulting in substantial morbidity, mortality, and enormous costs. In this paper, a digital light processing (DLP) based 3D printing system is employed to rapidly manufacture photocurable thermoset polymers and nanocomposites for potential antibacterial applications. This work shows how nanoparticles that present antibacterial properties can be added to traditional DLP manufacturing and their effects on the physical properties. In this paper, titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles in the 10 to 30-nm range are mixed with photocurable resins for rapid 3D printing and prototyping. The two resins used are a standard photopolymer rapid resin and an ABS-like photopolymer rapid resin. A 1% composite percentage is utilized to avoid the requirement of modification to the printing system due to greatly increased viscosity. Tensile testing data, contact angle data, and abrasion data are performed on a total of four different composites and two controls. These composites have shown a tensile strength of 29.53 MPa. At the 1% nanoparticle weight concentration, the 3D printing nanocomposites are transparent and demonstrate a complete penetration of particles throughout the entire print. The detailed experimental characterization will be conducted to understand the 3D printed material’s mechanical properties and microstructures fully. This research can enhance public health by providing a novel approach to control the spread of bacteria and other microbial.
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Zheng, Zhouyuan, Parth Bansal, and Yumeng Li. "Numerical Study on Antibacterial Effects of Bio-Inspired Nanostructured Surface." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23594.

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Abstract Natural bactericidal surfaces are found on the wings of cicada and dragonfly that compose of nanopatterns such as nanopillar arrays. Experimental studies have unveiled that the nanopillars can penetrate the bacterial walls or stretch them, resulting in the cell death. This offers an attractive “chemical-free” and wide-spectrum strategy to fight against bacteria-related infections and fouling, especially for implant-associated infections (IAIs). However, what is the fundamental mechanism and key factors governing the bactericidal performance of the nanostructured surface is the critical research questions need to be answered to realize its full potential. In this work, we developed mechanical single cell model of bacteria based on finite element analysis (FEA) to simulate the interactions between different strains of bacteria and the nanostructured surface. The nanostructured surface contains nanopillar arrays, which are made of polymer materials. Different strains of bacteria are simulated by adopting the corresponding geometry and material properties from experimental values. The mechanical responses of the bacteria cell on the nanopillar arrays with various configurations are studied based on estimated stress and strain distributions within the cell.
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Terzić, Jelena, Marina Stanković, and Olgica Stefanović. "ANTIBIOFILM ACTIVITY OF SELECTED PLANT SPECIES." In 1st INTERNATIONAL Conference on Chemo and BioInformatics. Institute for Information Technologies, University of Kragujevac, 2021. http://dx.doi.org/10.46793/iccbi21.280t.

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Bacterial biofilm is a complex community of bacterial cells enclosed in a polymer matrix and attached to a biotic or abiotic substrate. In this living form the bacteria are more resistant to antimicrobial agents than in the form of planktonic cells. Biofilm is a common cause of chronic infections in humans, so due to the growing resistance to antibiotics, alternative methods for controlling infections using medicinal plants have been proposed. In this study, the antibiofilm activity of ethanol and acetone extracts of plants Lamium album, Achillea millefolium and Agrimonia eupatoria against eight clinical isolates of human pathogenic bacteria was examined. Inhibition of biofilm formation was demonstrated using the crystal violet test and the effect on metabolic activity was confirmed by the use of resazurin dye test. Ethanol extract of L. album showed the greatest activity against P. aeruginosa (PA9) at a concentration of 20 mg/ml (> 80% of inhibition), while acetone extract acted at a concentration of 5 mg/ml (≥ 18%) against Klebsiella sp. (K9). At a concentration of 10 mg/ml, the ethanol extract of A. millefolium was effective against E. coli (E16) and P. aeruginosa (PA8) (> 70%), while the acetone extract was effective at 2.5 mg/ml (> 80%) against E. coli (E16). Ethanol and acetone extracts of A. eupatoria were effective at a concentration of 10 mg/ml (> 50%) against E. coli (E16). The antibiofilm activity of the tested plant extracts on certain clinical isolates indicates their great potential in the treatment of infections caused by biofilm-producing bacteria.
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Sultana, Sharmin, Md Sad Salabi Sawrav, Snygdha Rani Das, Mehfuz Alam, Md Abdul Aziz, Md Al-Amin Hossain, and Md Azizul Haque. "Isolation and Biochemical Characterization of Cellulase Producing Goat Rumen Bacteria." In International Conference on Emerging Trends in Engineering and Advanced Science. AIJR Publisher, 2022. http://dx.doi.org/10.21467/proceedings.123.12.

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Cellulose is the most prevalent polymer on the planet and has long been utilized for a variety of industrial applications. The study's goal was to screen and isolate cellulase-producing bacteria from the rumen of a goat collected from different location of Dinajpur district. To do so, rumen content samples from two distinct goats were collected. In this investigation, rumen cellulase-producing bacteria were isolated and characterized after serial dilution of five isolates up to six fold and inoculation into Nutrient agar. Following that, all of the isolates were underwent Methyl Red (MR) test & Voges-Proskauer (VP) test to identify organism’s metabolic pathway, Triple Sugar Iron Agar (TSI) Test to determine bacterial ability to utilize sugar, Motility Indole and Urease activity test (MIU) to determine motility, Urease utilization and can produce Indole or not, Citrate utilization test to utilize citrate as carbon and energy source, Oxidase test, Catalase test to check the presence of catalytic enzyme. The result revealed the colonial characterization of bacteria and also where proven all five isolates are promising enough and superior in quality to produce cellulose.
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Reports on the topic "Bacterial polymers"

1

Jelinek, Raz, Paul Dawson, Timothy Hanks, William Pennington, and Julie Northcutt. Bacterial sensors for food processing environments. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598157.bard.

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The overall objective of this project was to develop a new bacterial contaminant sensor based upon polydiacetylene(PDA) which is a unique polymer that changes color and configuration in response to external molecular stimuli. While this polymer has been well studied and has been shown to respond to bacterial stimuli in the laboratory, application to food processing environments has not been demonstrated. One hurdle in the application of biosensors in a food processing environment is interference of food sanitizers with the detection of bacteria. Common food sanitizers were evaluated for their response to PDA and different concentrations paving the way for use of modified PDAs developed by the research team to be used in food plants. Further development of PDA bacterial sensors focused on simplifying its application by immobilizing PDA on cotton and paper for use on swabs, wipes and dip papers. Increasing the sensitivity of PDAs was investigated by attaching fluorophores. Future and continued work will include the decoration of PDAs with apatmers to improve the specificity of the biosensor to food pathogens.
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Husson, Scott M., Viatcheslav Freger, and Moshe Herzberg. Antimicrobial and fouling-resistant membranes for treatment of agricultural and municipal wastewater. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598151.bard.

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This research project introduced a novel membrane coating strategy to combat biofouling, which is a major problem for the membrane-based treatment of agricultural and municipal wastewaters. The novelty of the strategy is that the membrane coatings have the unique ability to switch reversibly between passive (antifouling) and active (antimicrobial) fouling control mechanisms. This dual-mode approach differs fundamentally from other coating strategies that rely solely on one mode of fouling control. The research project had two complementary objectives: (1) preparation, characterization, and testing of dual-mode polymer nanolayers on planar surfaces and (2) evaluation of these nanolayers as membrane modifiers. The first objective was designed to provide a fundamental understanding of how polymer nanolayer chemistry and structure affect bacterial deposition and to demonstrate the reversibility of chemical switching. The second objective, which focused on membrane development, characterization, and testing, was designed to demonstrate methods for the production of water treatment membranes that couple passive and active biofouling control mechanisms. Both objectives were attained through synergistic collaboration among the three research groups. Using planar silicon and glass surfaces, we demonstrated using infrared spectroscopy that this new polymer coating can switch reversibly between the anti-fouling, zwitterion mode and an anti-microbial, quaternary amine mode. We showed that switching could be done more than 50 times without loss of activity and that the kinetics for switching from a low fouling zwitterion surface to an antimicrobial quaternary amine surface is practical for use. While a low pH was required for switching in the original polymer, we illustrated that by slightly altering the chemistry, it is possible to adjust the pH at which the switching occurs. A method was developed for applying the new zwitterionic surface chemistry onto polyethersulfone (PES) ultrafiltration membranes. Bacteria deposition studies showed that the new chemistry performed better than other common anti-fouling chemistries. Biofilm studies showed that PESultrafiltration membranes coated with the new chemistry accumulated half the biomass volume as unmodified membranes. Biofilm studies also showed that PES membranes coated with the new chemistry in the anti-microbial mode attained higher biofilm mortality than PES membranes coated with a common, non-switchablezwitterionic polymer. Results from our research are expected to improve membrane performance for the purification of wastewaters prior to use in irrigation. Since reduction in flux due to biofouling is one of the largest costs associated with membrane processes in water treatment, using dual-mode nanolayer coatings that switch between passive and active control of biofouling and enable detachment of attached biofoulants would have significant economic and societal impacts. Specifically, this research program developed and tested advanced ultrafiltration membranes for the treatment of wastewaters. Such membranes could find use in membrane bioreactors treating municipal wastewater, a slightly upgraded version of what presently is used in Israel for irrigation. They also may find use for pretreatment of agricultural wastewaters, e.g., rendering facility wastewater, prior to reverse osmosis for desalination. The need to desalinate such impaired waters water for unlimited agricultural use is likely in the near future.
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Morrison, Mark, and Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7695844.bard.

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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Rahimipour, Shai, and David Donovan. Renewable, long-term, antimicrobial surface treatments through dopamine-mediated binding of peptidoglycan hydrolases. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597930.bard.

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There is a need for renewable antimicrobial surface treatments that are semi- permanent, can eradicate both biofilms and planktonic pathogens over long periods of time and that do not select for resistant strains. This proposal describes a dopamine binding technology that is inexpensive, bio-friendly, non-toxic, and uses straight-forward commercially available products. The antimicrobial agents are peptidoglycanhydrolase enzymes that are non-toxic and highly refractory to resistance development. The goal of this project is to create a treatment that will be applicable to a wide variety of surfaces and will convey long-lasting antimicrobial activity. Although the immediate goal is to create staphylolytic surfaces, the technology should be applicable to any pathogen and will thus contribute to no less than 3 BARD priorities: 1) increased animal production by protecting animals from invasive and emerging diseases, 2) Antimicrobial food packaging will improve food safety and security and 3) sustainable bio- energy systems will be supported by coating fermentation vats with antimicrobials that could protect ethanolic fermentations from Lactobacillus contamination that reduces ethanol yields. The dopamine-based modification of surfaces is inspired by the strong adhesion of mussel adhesion proteins to virtually all types of surfaces, including metals, polymers, and inorganic materials. Peptidoglycanhydrolases (PGHs) meet the criteria of a surface bound antimicrobial with their site of action being extracellular peptidoglycan (the structural basis of the bacterial cell wall) that when breached causes osmotic lysis. As a proof of principle, we will develop technology using peptidoglycanhydrolase enzymes that target Staphylococcus aureus, a notoriously contagious and antimicrobial-resistant pathogen. We will test for susceptibility of the coating to a variety of environmental stresses including UV light, abrasive cleaning and dessication. In order to avoid resistance development, we intend to use three unique, synergistic, simultaneous staphylococcal enzyme activities. The hydrolases are modular such that we have created fusion proteins with three lytic activities that are highly refractory to resistance development. It is essential to use multiple simultaneous activities to avoid selecting for antimicrobial resistant strains. This strategy is applicable to both Gram positive and negative pathogens. We anticipate that upon completion of this award the technology will be available for commercialization within the time required to achieve a suitable high volume production scheme for the required enzymes (~1-2 years). We expect the modified surface will remain antimicrobial for several days, and when necessary, the protocol for renewal of the surface will be easily applied in a diverse array of environments, from food processing plants to barnyards.
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5

Lenz, Mark. RV POSEIDON Fahrtbericht / Cruise Report POS536/Leg 1. GEOMAR, October 2020. http://dx.doi.org/10.3289/geomar_rep_ns_56_2020.

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DIPLANOAGAP: Distribution of Plastics in the North Atlantic Garbage Patch Ponta Delgada (Portugal) – Malaga (Spain) 17.08. – 12.09.2019 The expedition POS 536 is part of a multi-disciplinary research initiative of GEOMAR investigating the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus will be on the vertical transfer of plastic debris from the surface and near-surface waters to the deep sea and on the processes that mediate this transport. The obtained data will help to develop quantitative models that provide information about the level of plastic pollution in the different compartments of the open ocean (surface, water column, seafloor). Furthermore, the effects of plastic debris on marine organisms in the open ocean will be assessed. The cruise will provide data about the: (1) abundance of plastic debris with a minimum size of 100 μm as well as the composition of polymer types in the water column at different depths from the sea surface to the seafloor including the sediment, (2) abundance and composition of plastic debris in organic aggregates (“marine snow”), (3) in pelagic and benthic organisms (invertebrates and fish) and in fecal pellets, (4) abundance and the identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.
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6

Beck, Aaron. RiverOceanPlastic: Land-ocean transfer of plastic debris in the North Atlantic, Cruise No. AL534/2, 05 March – 26 March 2020, Malaga (Spain) – Kiel (Germany). GEOMAR Helmholtz Centre for Ocean Research Kiel, 2020. http://dx.doi.org/10.3289/cr_al534-2.

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Cruise AL534/2 is part of a multi-disciplinary research initiative as part of the JPI Oceans project HOTMIC and sought to investigate the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus of the cruise was on the horizontal transfer of plastic debris from major European rivers into shelf regions and on the processes that mediate this transport. Stations were originally chosen to target the outflows of major European rivers along the western Europe coast between Malaga (Spain) and Kiel (Germany), although some modifications were made in response to inclement weather. In total, 16 stations were sampled along the cruise track. The sampling scheme was similar for most stations, and included: 1) a CTD cast to collect water column salinity and temperature profiles, and discrete samples between surface and seafloor, 2) sediment sampling with Van Veen grab and mini-multi corer (mini-MUC), 3) suspended particle and plankton sampling using a towed Bongo net and vertical WP3 net, and 4) surface neusten sampling using a catamaran trawl. At a subset of stations with deep water, suspended particles were collected using in situ pumps deployed on a cable. During transit between stations, surface water samples were collected from the ship’s underway seawater supply, and during calm weather, floating litter was counted by visual survey teams. The samples and data collected on cruise AL534/2 will be used to determine the: (1) abundance of plastic debris in surface waters, as well as the composition of polymer types, originating in major European estuaries and transported through coastal waters, (2) abundance and composition of microplastics (MP) in the water column at different depths from the sea surface to the seafloor including the sediment, (3) abundance and composition of plastic debris in pelagic and benthic organisms (invertebrates), (4) abundance and identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.
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7

Willis, C., F. Jorgensen, S. A. Cawthraw, H. Aird, S. Lai, M. Chattaway, I. Lock, E. Quill, and G. Raykova. A survey of Salmonella, Escherichia coli (E. coli) and antimicrobial resistance in frozen, part-cooked, breaded or battered poultry products on retail sale in the United Kingdom. Food Standards Agency, May 2022. http://dx.doi.org/10.46756/sci.fsa.xvu389.

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Frozen, breaded, ready-to-cook chicken products have been implicated in outbreaks of salmonellosis. Some of these outbreaks can be large. For example, one outbreak of Salmonella Enteritidis involved 193 people in nine countries between 2018 and 2020, of which 122 cases were in the UK. These ready-to-cook products have a browned, cooked external appearance, which may be perceived as ready-to-eat, leading to mishandling or undercooking by consumers. Continuing concerns about these products led FSA to initiate a short-term (four month), cross-sectional surveillance study undertaken in 2021 to determine the prevalence of Salmonella spp., Escherichia coli and antimicrobial resistance (AMR) in frozen, breaded or battered chicken products on retail sale in the UK. This study sought to obtain data on AMR levels in Salmonella and E. coli in these products, in line with a number of other FSA instigated studies of the incidence and nature of AMR in the UK food chain, for example, the systematic review (2016). Between the beginning of April and the end of July 2021, 310 samples of frozen, breaded or battered chicken products containing either raw or partly cooked chicken, were collected using representative sampling of retailers in England, Wales, Scotland and Northern Ireland based on market share data. Samples included domestically produced and imported chicken products and were tested for E. coli (including extended-spectrum beta-lactamase (ESBL)-producing, colistin-resistant and carbapenem-resistant E. coli) and Salmonella spp. One isolate of each bacterial type from each contaminated sample was randomly selected for additional AMR testing to determine the minimum inhibitory concentration (MIC) for a range of antimicrobials. More detailed analysis based on Whole Genome Sequencing (WGS) data was used to further characterise Salmonella spp. isolates and allow the identification of potential links with human isolates. Salmonella spp. were detected in 5 (1.6%) of the 310 samples and identified as Salmonella Infantis (in three samples) and S. Java (in two samples). One of the S. Infantis isolates fell into the same genetic cluster as S. Infantis isolates from three recent human cases of infection; the second fell into another cluster containing two recent cases of infection. Countries of origin recorded on the packaging of the five Salmonella contaminated samples were Hungary (n=1), Ireland (n=2) and the UK (n=2). One S. Infantis isolate was multi-drug resistant (i.e. resistant to three different classes of antimicrobials), while the other Salmonella isolates were each resistant to at least one of the classes of antimicrobials tested. E. coli was detected in 113 samples (36.4%), with counts ranging from <3 to >1100 MPN (Most Probable Number)/g. Almost half of the E. coli isolates (44.5%) were susceptible to all antimicrobials tested. Multi-drug resistance was detected in 20.0% of E. coli isolates. E. coli isolates demonstrating the ESBL (but not AmpC) phenotype were detected in 15 of the 310 samples (4.8%) and the AmpC phenotype alone was detected in two of the 310 samples (0.6%) of chicken samples. Polymerase Chain Reaction (PCR) testing showed that five of the 15 (33.3%) ESBL-producing E. coli carried blaCTX-M genes (CTX-M-1, CTX-M-55 or CTX-M-15), which confer resistance to third generation cephalosporin antimicrobials. One E. coli isolate demonstrated resistance to colistin and was found to possess the mcr-1 gene. The five Salmonella-positive samples recovered from this study, and 20 similar Salmonella-positive samples from a previous UKHSA (2020/2021) study (which had been stored frozen), were subjected to the cooking procedures described on the sample product packaging for fan assisted ovens. No Salmonella were detected in any of these 25 samples after cooking. The current survey provides evidence of the presence of Salmonella in frozen, breaded and battered chicken products in the UK food chain, although at a considerably lower incidence than reported in an earlier (2020/2021) study carried out by PHE/UKHSA as part of an outbreak investigation where Salmonella prevalence was found to be 8.8%. The current survey also provides data on the prevalence of specified AMR bacteria found in the tested chicken products on retail sale in the UK. It will contribute to monitoring trends in AMR prevalence over time within the UK, support comparisons with data from other countries, and provide a baseline against which to monitor the impact of future interventions. While AMR activity was observed in some of the E. coli and Salmonella spp. examined in this study, the risk of acquiring AMR bacteria from consumption of these processed chicken products is low if the products are cooked thoroughly and handled hygienically.
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