Auswahl der wissenschaftlichen Literatur zum Thema „Biofilm-detached“
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Zeitschriftenartikel zum Thema "Biofilm-detached":
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Behnke, Sabrina, Albert E. Parker, Dawn Woodall und Anne K. Camper. „Comparing the Chlorine Disinfection of Detached Biofilm Clusters with Those of Sessile Biofilms and Planktonic Cells in Single- and Dual-Species Cultures“. Applied and Environmental Microbiology 77, Nr. 20 (19.08.2011): 7176–84. http://dx.doi.org/10.1128/aem.05514-11.
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ABSTRACTAlthough the detachment of cells from biofilms is of fundamental importance to the dissemination of organisms in both public health and clinical settings, the disinfection efficacies of commonly used biocides on detached biofilm particles have not been investigated. Therefore, the question arises whether cells in detached aggregates can be killed with disinfectant concentrations sufficient to inactivate planktonic cells.Burkholderia cepaciaandPseudomonas aeruginosawere grown in standardized laboratory reactors as single species and in coculture. Cluster size distributions in chemostats and biofilm reactor effluent were measured. Chlorine susceptibility was assessed for planktonic cultures, attached biofilm, and particles and cells detached from the biofilm. Disinfection tolerance generally increased with a higher percentage of larger cell clusters in the chemostat and detached biofilm. Samples with a lower percentage of large clusters were more easily disinfected. Thus, disinfection tolerance depended on the cluster size distribution rather than sample type for chemostat and detached biofilm. Intact biofilms were more tolerant to chlorine independent of species. Homogenization of samples led to significantly increased susceptibility in all biofilm samples as well as detached clusters for single-speciesB. cepacia,B. cepaciain coculture, andP. aeruginosain coculture. The disinfection efficacy was also dependent on species composition; coculture was advantageous to the survival of both species when grown as a biofilm or as clusters detached from biofilm but, surprisingly, resulted in a lower disinfection tolerance when they were grown as a mixed planktonic culture.
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Liu, Jia, Jun-Qi Ling, Kai Zhang, Li-Jun Huo und Yang Ning. „Effect of Sodium Fluoride, Ampicillin, and Chlorhexidine on Streptococcus mutans Biofilm Detachment“. Antimicrobial Agents and Chemotherapy 56, Nr. 8 (04.06.2012): 4532–35. http://dx.doi.org/10.1128/aac.00885-12.
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ABSTRACTWe examined the effect of three clinically used antimicrobials onStreptococcus mutansUA159 biofilm detachment under flow conditions. Sodium fluoride (NaF) and chlorhexidine at MIC levels promoted biofilm detachment and inhibited detachment when concentrations were higher than the MIC and reduced detached-cell viability only at high concentrations. Ampicillin at all concentrations tested inhibited detachment and reduced the percentage of viable biofilm-detached cells. All the three antimicrobial treatments reduced biofilm live/dead cell ratios.
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Liu, Jia, Jun-Qi Ling, Kai Zhang und Christine D. Wu. „Physiological properties ofStreptococcus mutansUA159 biofilm-detached cells“. FEMS Microbiology Letters 340, Nr. 1 (14.01.2013): 11–18. http://dx.doi.org/10.1111/1574-6968.12066.
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Perpetuini, Giorgia, Fabrizia Tittarelli, Carlo Perla und Rosanna Tofalo. „Influence of Different Aggregation States on Volatile Organic Compounds Released by Dairy Kluyveromyces marxianus Strains“. Foods 11, Nr. 18 (19.09.2022): 2910. http://dx.doi.org/10.3390/foods11182910.
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Kluyveromyces marxianus has the ability to contribute to the aroma profile of foods and beverages since it is able to produce several volatile organic compounds (VOCs). In this study, 8 dairy K. marxianus strains, previously selected for their adhesion properties, were tested for VOCs production when grown in different conditions: planktonic, biofilm-detached, and MATS forming-cells. It was shown that biofilm-detached cells were mainly able to produce higher alcohols (64.57 mg/L), while esters were mainly produced by planktonic and MATS forming-cells (117.86 and 94.90 mg/L, respectively). Moreover, K. marxianus biofilm-detached cells were able to produce VOCs with flavor and odor impacts, such as ketons, phenols, and terpenes, which were not produced by planktonic cells. In addition, specific unique compounds were associated to the different conditions tested. Biofilm-detached cells were characterized by the production of 9 unique compounds, while planktonic and MATS forming-cells by 7 and 12, respectively. The obtained results should be exploited to modulate the volatilome of foods and beverages and improve the production of certain compounds at the industrial level. Further studies will be carried out to better understand the genetic mechanisms underlying the metabolic pathways activated under different conditions.
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Wilson, Suzanne, Martin A. Hamilton, Gordon C. Hamilton, Margo R. Schumann und Paul Stoodley. „Statistical Quantification of Detachment Rates and Size Distributions of Cell Clumps from Wild-Type (PAO1) and Cell Signaling Mutant (JP1) Pseudomonas aeruginosa Biofilms“. Applied and Environmental Microbiology 70, Nr. 10 (Oktober 2004): 5847–52. http://dx.doi.org/10.1128/aem.70.10.5847-5852.2004.
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ABSTRACT The detachment of cells from bacterial biofilms is an important, yet poorly understood and largely unquantified phenomenon. Detached cell clumps from medical devices may form microemboli and lead to metastasis, especially if they are resistant to host defenses and antibiotics. In manufacturing plants detached clumps entering a process stream decrease product quality. Two strains of Pseudomonas aeruginosa, a wild type (PAO1) and a cell signaling mutant (JP1), were studied to (i) quantify and model detachment patterns and (ii) determine the influence of cell signaling on detachment. We collected effluent from a biofilm flowthrough reactor and determined the size distribution for cell detachment events by microscopic examination and image analysis. The two strains were similar in terms of both biofilm structure and detachment patterns. Most of the detachment events were single-cell events; however, multiple-cell detachment events contributed a large fraction of the total detached cells. The rates at which events containing multiple cells detached from the biofilm were estimated by fitting a statistical model to the size distribution data. For events consisting of at least 1,000 cells, the estimated rates were 4.5 events mm−2 min−1 for PAO1 and 4.3 events mm−2 min−1 for JP1. These rates may be significant when they are scaled up to the total area of a real biofilm-contaminated medical device surface and to the hours or days of patient exposure.
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Watanabe, Yoshimasa, Chulhee Lee, Makoto Koike und Masayoshi Ishiguro. „Nitrification Kinetics and Simultaneous Removal of Biomass and Phosphorus in Rotating Biological Contactors“. Water Science and Technology 22, Nr. 3-4 (01.03.1990): 169–78. http://dx.doi.org/10.2166/wst.1990.0198.
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This paper presents some important aspects of the Rotating Biological Contactor. (1) Steady-state biofilm kinetics and its application to the design of an RBC aiming at nitrification : Using the proposed kinetics in which the flux of rate-limiting substrate is expressed as a function of the bulk substrate concentration, liquid boundary layer thickness, liquid film thickness, and molecular diffusion coefficient and intrinsic reaction rate of the substrate, the relationship between the bulk ammonia concentration and ammonia flux was predicted at various sizes and rotating speeds of disk. Experimental verification of the predicted results was also made. A new disk media, i.e., reticulated media with surface protrusions,was proposed to promote the external diffusion of soluble substrates to the biofilm, and to reduce the disk weight. (2) Simultaneous removal of the detached biomass and precipitated phosphorous in a two-storey RBC:A two-storey RBC, whose upper and lower parts function as the RBC trough and storage space of the detached biomass, was operated in a four-staged unit. Experimental investigation showed that the phosphorus precipitated by aluminium was adsorbed to the biofilm, and settled into the lower part as the detached biomass. The removal efficiency of the detached biomass was very high resulting in an effluent suspended solids concentration of about 10 ppm.
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Bester, Elanna, Gideon Wolfaardt, Lydia Joubert, Kerstin Garny und Sanja Saftic. „Planktonic-Cell Yield of a Pseudomonad Biofilm“. Applied and Environmental Microbiology 71, Nr. 12 (Dezember 2005): 7792–98. http://dx.doi.org/10.1128/aem.71.12.7792-7798.2005.
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ABSTRACT Biofilm cells differ phenotypically from their free-floating counterparts. Differential growth rates in biofilms are often referred to, particularly in response to limited diffusion of oxygen and nutrients. We observed growth rates of attached Pseudomonas sp. strain CT07 cells that were notably higher than the maximum specific growth rate measured in batch culture. Despite dilution rates in continuous flow cells that exceeded the maximum planktonic specific growth rate by 58 times, sampling of the effluent revealed >109 cells ml−1, suggesting that biofilms function as a source of planktonic cells through high cell yield and detachment. Further investigation demonstrated considerable planktonic cell yield from biofilms as young as 6 h, indicating that detachment is not limited to established biofilms. These biofilm-detached cells were more sensitive to a commercial biocide than associated biofilm- and chemostat-cultivated populations, implying that detached biofilm cells exhibit a character that is distinct from that of attached and planktonic cell populations.
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Hou, Shuyu, Zhigang Liu, Anne W. Young, Sheron L. Mark, Neville R. Kallenbach und Dacheng Ren. „Effects of Trp- and Arg-Containing Antimicrobial-Peptide Structure on Inhibition of Escherichia coli Planktonic Growth and Biofilm Formation“. Applied and Environmental Microbiology 76, Nr. 6 (22.01.2010): 1967–74. http://dx.doi.org/10.1128/aem.02321-09.
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ABSTRACT Biofilms are sessile microbial communities that cause serious chronic infections with high morbidity and mortality. In order to develop more effective approaches for biofilm control, a series of linear cationic antimicrobial peptides (AMPs) with various arginine (Arg or R) and tryptophan (Trp or W) repeats [(RW) n -NH2, where n = 2, 3, or 4] were rigorously compared to correlate their structures with antimicrobial activities affecting the planktonic growth and biofilm formation of Escherichia coli. The chain length of AMPs appears to be important for inhibition of bacterial planktonic growth, since the hexameric and octameric peptides significantly inhibited E. coli growth, while tetrameric peptide did not cause noticeable inhibition. In addition, all AMPs except the tetrameric peptide significantly reduced E. coli biofilm surface coverage and the viability of biofilm cells, when added at inoculation. In addition to inhibition of biofilm formation, significant killing of biofilm cells was observed after a 3-hour treatment of preformed biofilms with hexameric peptide. Interestingly, treatment with the octameric peptide caused significant biofilm dispersion without apparent killing of biofilm cells that remained on the surface; e.g., the surface coverage was reduced by 91.5 ± 3.5% by 200 μM octameric peptide. The detached biofilm cells, however, were effectively killed by this peptide. Overall, these results suggest that hexameric and octameric peptides are potent inhibitors of both bacterial planktonic growth and biofilm formation, while the octameric peptide can also disperse existing biofilms and kill the detached cells. These results are helpful for designing novel biofilm inhibitors and developing more effective therapeutic methods.
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Stoodley, Paul, Suzanne Wilson, Luanne Hall-Stoodley, John D. Boyle, Hilary M. Lappin-Scott und J. W. Costerton. „Growth and Detachment of Cell Clusters from Mature Mixed-Species Biofilms“. Applied and Environmental Microbiology 67, Nr. 12 (01.12.2001): 5608–13. http://dx.doi.org/10.1128/aem.67.12.5608-5613.2001.
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ABSTRACT Detachment from biofilms is an important consideration in the dissemination of infection and the contamination of industrial systems but is the least-studied biofilm process. By using digital time-lapse microscopy and biofilm flow cells, we visualized localized growth and detachment of discrete cell clusters in mature mixed-species biofilms growing under steady conditions in turbulent flow in situ. The detaching biomass ranged from single cells to an aggregate with a diameter of approximately 500 μm. Direct evidence of local cell cluster detachment from the biofilms was supported by microscopic examination of filtered effluent. Single cells and small clusters detached more frequently, but larger aggregates contained a disproportionately high fraction of total detached biomass. These results have significance in the establishment of an infectious dose and public health risk assessment.
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Fux, C. A., S. Wilson und P. Stoodley. „Detachment Characteristics and Oxacillin Resistance of Staphyloccocus aureus Biofilm Emboli in an In Vitro Catheter Infection Model“. Journal of Bacteriology 186, Nr. 14 (15.07.2004): 4486–91. http://dx.doi.org/10.1128/jb.186.14.4486-4491.2004.
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ABSTRACT Catheter-related bloodstream infections due to Staphylococcus aureus are of increasing clinical importance. The pathophysiological steps leading to colonization and infection, however, are still incompletely defined. We observed growth and detachment of S. aureus biofilms in an in vitro catheter-infection model by using time-lapse microscopy. Biofilm emboli were characterized by their size and their susceptibility for oxacillin. Biofilm dispersal was found to be a dynamic process in which clumps of a wide range of diameters detach. Large detached clumps were highly tolerant to oxacillin compared with exponential-phase planktonic cultures. Interestingly, the degree of antibiotic tolerance in stationary-phase planktonic cultures was equal to that in the large clumps. The mechanical disruption of large clumps reduced the minimal bactericidal concentration (MBC) by more than 1,000 times. The MBC for whole biofilm effluent, consisting of particles with an average number of 20 bacteria was 3.5 times higher than the MBC for planktonic cultures. We conclude that the antibiotic resistance of detached biofilm particles depends on the embolus size and could be attributed to nutrient-limited stationary-phase physiology of cells within the clumps. We hypothesize that the detachment of multicellular clumps may explain the high rate of symptomatic metastatic infections seen with S. aureus.
Dissertationen zum Thema "Biofilm-detached":
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Behnke, Sabrina. „Disinfection susceptibilities of detached biofilm clusters compared to planktonic cells and biofilms in single species and dual species cultures“. Diss., Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/behnke/BehnkeS0811.pdf.
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Detachment of cells and clusters from biofilms is an important process in the dissemination of microorganisms in industrial, environmental, and clinical settings but the disinfection susceptibilities of these cell clusters have not been sufficiently characterized. With the help of fluorescent microscopy and image analysis, naturally detaching cells and clusters from single species and dual species biofilms of Burkholderia cepacia and Pseudomonas aeruginosa grown in biofilm tubing reactors were analyzed for cluster size distributions and compared to the cluster sizes in chemostat cultures. The commonly used oxidizing agents free chlorine, chlorine dioxide and dissolved ozone were used for disinfection experiments and susceptibilities of detached clusters, planktonic cells, and intact biofilms in single species and dual species cultures were determined. Additionally, disinfection rates were calculated for chlorine and chlorine dioxide disinfection for all sample types and species. In experiments with chlorine as the disinfectant, a correlation between cluster sizes and disinfection efficacy was observed for single species only. Samples with the higher percentage of large clusters were more tolerant than samples with fewer large clusters. Chemostat samples and detached clusters from dual species reactors contained lower numbers of large clusters but were equally or less susceptible than their single species counterparts. Biofilms required chlorine doses up to ten times higher than chemostat or detached biofilm cells for total inactivation. Chlorine dioxide disinfection was independent of cluster size so that chemostat cells and detached clusters were similar with respect to log reductions and disinfection rates. Dual species chemostat cells, detached clusters, and biofilms were more tolerant to chlorine dioxide than the single species samples. As with chlorine, biofilms required much higher chlorine dioxide doses for total inactivation. Ozone was very efficient against B. cepacia chemostat cells and detached clusters but failed to inactivate biofilm samples with the concentrations used in this study. In general, detached clusters were more similar to chemostat cells and very different from biofilms with respect to disinfection susceptibilities and disinfection rates suggesting that biofilm-specific physical and physiological protection mechanisms may be lost shortly after the detachment event or may be absent in small clusters. 'Co-authored by Albert E. Parker, Dawn Woodall, and Anne K. Camper.'
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Khelissa, Simon Oussama. „Caractérisation des propriétés physiologiques associées aux cellules détachées de biofilms et étude des interactions aux interfaces entre bactéries et matériaux : cas de Staphylococcus aureus et Pseudomonas aeruginosa“. Electronic Thesis or Diss., Lille 1, 2017. http://www.theses.fr/2017LIL10195.
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Le biofilm est à l’origine d’infections nosocomiales et d’intoxications alimentaires dans les secteurs alimentaire et hospitalier. Les bactéries structurées en biofilm peuvent se détacher et coloniser de nouvelles surfaces. Le risque microbiologique associé aux bactéries détachées de biofilm est peu étudié. Les travaux de thèse ont concerné, l’étude de l’effet des conditions de croissance sur les propriétés physicochimiques de surface de Staphylococcus aureus et Pseudomonas aeruginosa sous leurs formes détachées de biofilm et planctoniques, ainsi que leurs adhésion sur l'acier inoxydable (SS) et le polycarbonate (PC). Le pouvoir pathogène des deux populations bactériennes a été étudié. Les résultats ont montré que les conditions et le mode de croissance influencent les propriétés de surface et par conséquent l’adhésion de S. aureus et P. aeruginosa sur le SS et le PC. De plus, la température de croissance, le type de surface et l’âge physiologique des bactéries influencent significativement leur production des facteurs de virulence et leur cytotoxicité envers les cellules HeLa. Dans un deuxième temps, l'effet de température de croissance sur la résistance des cellules détachées de biofilm et planctoniques au chlorure de benzalkonium (BAC) a été évalué. Pour comprendre les mécanismes de résistance à l’échelle cellulaire, les lésions des membranes bactériennes associées au BAC ont été suivies par l’efflux des ions K+ intracellulaires. En outre, la fluidité membranaire de deux populations bactériennes a été caractérisée à travers l'étude de profils d'acides gras membranaires. Les résultats ont montré que la résistance au BAC dépend de la température et de l’état physiologique des bactériesThe biofilm formation in food and medical sectors represents a significant source of foodborne and nosocomial diseases. Bacteria structured in biofilm can detach and colonize new surfaces. The microbiological risk associated with biofilm-detached bacteria is poorly studied. On one hand, the thesis concerned the study of growth conditions effect on the bacterial surface physicochemical properties as well as the adhesion of Staphylococcus aureus and Pseudomonas aeruginosa biofilm-detached and planktonic cells to stainless steel (SS) and polycarbonate (PC). The pathogenicity of both bacterial populations has also been studied. The results showed that the conditions and the mode of growth influence the surface properties and consequently the adhesion of S. aureus and P. aeruginosa on the SS and the PC. In addition, growth temperature, surface type and physiological age of bacterial cells significantly influence their production of virulence factors and their cytotoxicity towards HeLa cells. On the other hand, the effect of growth temperature on the resistance of biofilm-detached and planktonic cells to benzalkonium chloride (BAC) was assessed. In order to understand the mechanisms of resistance at the cellular level, bacterial membrane damage associated with BAC was assessed by the efflux of intracellular K+ ions. In addition, the membrane fluidity of bacterial populations was characterized through the study of membrane fatty acid profiles. The results showed that resistance to BAC depends on the temperature and physiological state of the studied bacteria