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  • grown
  • Transmitted light and epifluorescent maximum projections of the confocal scanning laser microscopy stacks are shown for a biofilm grown in the flow cell at 1 ml/min. (nih.gov)
  • You are looking at an amazing image of a dime-sized biofilm of Pseudomonas aeruginosa, grown and photographed by Scott Chimileski - a biologist, photographer, and writer at the Kolter Lab at Harvard Medical School. (woundsource.com)
  • Aerobically grown P. aeruginosa cells are tobramycin sensitive but chlorate tolerant. (asm.org)
  • P. aeruginosa biofilms were grown for 18 h in a constant depth film fermenter, either with mucin-containing artificial sputum medium (ASM+), artificial sputum medium without mucin (ASM-), or Luria-Bertani broth (LB). This yielded 100 μm thick biofilms, that differed in their amounts of matrix eDNA and polysaccharides. (rug.nl)
  • Low-load-compression-testing followed by three-element Maxwell analyses, showed that the fastest relaxation component, associated with unbound water, was most important in LB-grown biofilms. (rug.nl)
  • Slower components due to water with dissolved polysaccharides, insoluble polysaccharides and eDNA, were most important in relaxation of ASM+-grown biofilms. (rug.nl)
  • ASM--grown biofilms showed intermediate stress relaxation. (rug.nl)
  • Concluding, stress relaxation of P. aeruginosa biofilms grown in different media revealed differences in matrix composition that, within the constraints of the antimicrobials and growth media applied, correlated with the matrix protection offered against different antimicrobials. (rug.nl)
  • Representative confocal images of Psl biofilms grown statically for 24 hours ( top ) and Pel biofilms cultivated for 48 hours ( bottom ) under flow conditions and treated with wild-type hydrolases or hydrolases that have point mutations to catalytic residues. (sciencemag.org)
  • Triclosan also enhances tobramycin killing of multiple Burkholderia cenocepacia and Staphylococcus aureus clinical isolates grown as biofilms. (asm.org)
  • When biofilms were grown under flowing liquid in simple environments with flat surfaces, matrix producers always outcompeted non-producers. (elifesciences.org)
  • Microscopic investigation of flow chamber-grown wild-type P. aeruginosa biofilms stained with different DNA stains suggested that the extracellular DNA is located primarily in the stalks of mushroom-shaped multicellular structures, with a high concentration especially in the outer part of the stalks forming a border between the stalk-forming bacteria and the cap-forming bacteria. (nih.gov)
  • tobramycin
  • Chlorate and the antibiotic tobramycin kill distinct metabolic populations in P. aeruginosa biofilms, where chlorate targets anaerobic cells that tolerate tobramycin. (asm.org)
  • Biofilms formed by an alginate-overproducing strain exhibit a highly structured architecture and are significantly more resistant to the antibiotic tobramycin than a biofilm formed by an isogenic nonmucoid strain. (asm.org)
  • This synergistic treatment significantly accelerated the killing of biofilms compared to that with tobramycin treatment alone, and the combination was effective against 6/7 CF clinical isolates compared to tobramycin treatment alone, including a tobramycin-resistant strain. (asm.org)
  • Interestingly, 3-oxo-C12-HSL was found to increase antibiotic susceptibility of isolated P. aeruginosa PAO1 and PDO300 persister cells to ciprofloxacin in a dose-dependent manner, although such synergistic effect was not observed with ofloxacin, tobramycin, tetracycline, carbenicillin, and gentamicin. (syr.edu)
  • The switch from the nonmucoid to the mucoid phenotype may provide profound advantages to the bacteria growing in biofilms, such as increasing their levels of resistance to antibiotics (such as tobramycin) and protecting them against the host immune system ( 30 , 35 , 44 , 52 ). (asm.org)
  • Tobramycin alone at concentrations of 10 μg ml−1 did not affect the biofilm, but were significantly enhanced by 9 mA cm−2. (montana.edu)
  • Jass, J., J.W. Costerton, and H.M. Lappin-Scott, "The Effect of Electrical Currents and Tobramycin on Pseudomonas aeruginosa Biofilms,"Journal of Industrial Microbiology, 15:234-242 (1995). (montana.edu)
  • confocal
  • Confocal laser scanning microscopy of biofilms formed in flow chambers showed that mutants deficient in alginate biosynthesis developed biofilms with a decreased proportion of viable cells than alginate-producing strains, indicating a role of alginate in viability of cells in biofilms. (asm.org)
  • Biofilms were monitored by confocal laser scanning microscopy (CLSM), and the numbers of viable cells and resistant mutants (4- and 16-fold MICs) were determined. (dtu.dk)
  • mutants
  • Here mutants deficient in the production of one or more of these polysaccharides were generated to investigate how these polymers interactively contribute to biofilm formation. (asm.org)
  • Alginate-deficient mutants showed enhanced extracellular DNA (eDNA)-containing surface structures impacting the biofilm architecture. (asm.org)
  • Using the flow cell culturing method, in which reproducible seeding phenotype in PAO1 wild-type was demonstrated, the effects of quorum sensing (QS) and rhamnolipid production (factors previously identified as important in determining biofilm structure) on seeding dispersal using knockout mutants isogenic with PAO1 was investigated. (montana.edu)
  • We explored the development of metabolically heterogeneous Pseudomonas aeruginosa biofilms using numerical models and laboratory knockout experiments on wild-type and chemotaxis-deficient mutants. (ntu.edu.sg)
  • Biofilms formed by lasIrhlI, pqsA and fliMpilA mutants contained less extracellular DNA than biofilms formed by the wild type, and the mutant biofilms were more susceptible to treatment with sodium dodecyl sulphate than the wild-type biofilm. (nih.gov)
  • antibiotics
  • The microorganism secretes a variety of materials to form an extracellular matrix that holds the biofilm together, and protects the bacteria from antibiotics and the immune system - making it challenging to eradicate. (woundsource.com)
  • A hallmark characteristic of biofilm bacteria is that they can be up to 1,000 times more resistant to antibiotics than their free-swimming counterparts ( 14 , 24 , 36 ). (asm.org)
  • How these antibiotics influence gene expression in the surviving biofilm population of P. aeruginosa is not clear. (asm.org)
  • However, planktonic bacteria dispersed from a biofilm usually no longer demonstrate increased levels of resistance to antibiotics, suggesting that the mode of growth is of major importance ( 45 ). (asm.org)
  • The combined use of antibiotics with low levels of electrical current has been reported to be more effective in controlling biofilms (the bioelectric effect) than antibiotics alone. (montana.edu)
  • An electrical colonisation cell was designed to study the effect of antibiotics on biofilms formed on a dialysis membrane away from the electrode surface. (montana.edu)
  • Understanding the dynamics behind the formation of such structures can aid in design of drug delivery systems, antibiotics, or physical systems for removal of biofilms. (ntu.edu.sg)
  • role in biofilm
  • The formation of characteristic mushroom-like structures required both Psl and alginate, whereas Pel appeared to play a role in biofilm cell density and/or the compactness of the biofilm. (asm.org)
  • Our results show that mutational mechanisms play a major role in biofilm antibiotic resistance and that theoretically optimized PK/PD parameters fail to suppress resistance development, suggesting that the increased antibiotic tolerance driven by the special biofilm physiology and architecture may raise the effective MPC, favoring gradual mutational resistance development, especially in mutator strains. (dtu.dk)
  • biomass
  • The amount of biofilm biomass required for full QS induction of the population increased as the flow rate increased. (nih.gov)
  • Accumulation of biofilm biomass in the tube biofilm reactor. (nih.gov)
  • The biofilm biomass for each harvested biofilm was measured by triplicate plate counts. (nih.gov)
  • The vertical dashed line indicates the biofilm biomass at which QS was fully induced (i.e., lasB expression at 100% of planktonic maximum). (nih.gov)
  • We hypothesized that as fluid flow rate in a biofilm system increased, the amount of biofilm biomass required for full QS induction of the population also would increase. (asm.org)
  • We used predictive modeling to gauge how flow conditions might affect the amount of biomass required for full QS induction of the population in a simple laboratory biofilm. (asm.org)
  • Several parameters were included in the model (see Table S1 in the supplemental material), including estimated per-cell signal production rate, biofilm biomass accumulation, Fickian diffusion of signal in the biofilm, and assumed geometry of a flat, two-dimensional biofilm. (asm.org)
  • The possible mechanisms of action of the bioelectric effect have been reported to involve electrophoresis, iontophoresis and electroporesis, thus overcoming the biofilm biomass and cell wall barriers. (montana.edu)
  • strains
  • went on to show that the strains could co-exist because the matrix producers made biofilms that created areas within the environment where the liquid flows very slowly or not at all. (elifesciences.org)
  • Alginate production is correlated to the development of impaired lung function, and P. aeruginosa strains isolated from chronically colonized lungs of CF patients are nearly always mucoid due to the overproduction of alginate. (asm.org)
  • Evidence that the extracellular DNA in P. aeruginosa biofilms and cultures is generated via lysis of a subpopulation of the bacteria was obtained through experiments where extracellular beta-galactosidase released from lacZ-containing P. aeruginosa strains was assessed. (nih.gov)
  • metabolically
  • In addition, biofilms have a greater number of dormant cells, termed "persisters," which are metabolically inert, making them tolerant to antimicrobials that target metabolically active processes ( 11 , 12 ). (asm.org)
  • shown to inhibit
  • In addition, the extrapolymeric matrix produced by biofilm bacteria has been shown to inhibit phagocytosis by cells of the immune system ( 34 ). (asm.org)
  • lung
  • Eventually, the environment in the CF lung causes P. aeruginosa to undergo a switch to a mucoid phenotype ( 11 , 25 ). (asm.org)
  • Initial microscopic observations of postmortem lung tissue and the sputa of patients suggested that P. aeruginosa forms biofilms in the CF lung ( 29 , 48 ). (asm.org)
  • Clinical observations link respiratory virus infection and Pseudomonas aeruginosa colonization in chronic lung disease, including cystic fibrosis (CF) and chronic obstructive pulmonary disease. (pnas.org)
  • infection
  • Alginates, which are overproduced by P. aeruginosa after infection of CF patients, are linear polyanionic exopolysaccharides composed of uronic acids ( 25 ). (asm.org)
  • mechanisms
  • Understanding the mechanisms of the development of mushroom-shaped biofilms helps to identify the multidrug-resistant regions. (ntu.edu.sg)
  • situ
  • Moreover, the amplification of mutator populations under antibiotic treatment by coselection with resistance mutations is for the first time demonstrated in situ for P. aeruginosa biofilms. (dtu.dk)
  • significantly
  • Transport of the antibiotic to the biofilm-substratum interface during the 21-min exposure to 100 micrograms/ml was found to be significantly impeded by the biofilm. (asm.org)
  • P. aeruginosa cell surface hydrophobicity and biofilm integrity were significantly altered due to the cleavage of nucleic acids by prodigiosin or the prodigiosin/copper(II) complex. (frontiersin.org)
  • exopolysaccharide
  • Given that the glycoside hydrolases PelA h and PslG h encoded in the pel and psl biosynthetic operons, respectively, are utilized for in vivo exopolysaccharide processing, we reasoned that these would provide specificity to target P. aeruginosa biofilms. (sciencemag.org)
  • eDNA
  • eDNA was found to mediate cell-cell interactions in biofilms ( 1 ). (asm.org)
  • this yielded 100-μm-thick biofilms that differed in their amounts of matrix environmental DNA (eDNA) and polysaccharides. (asm.org)
  • distinct
  • Biofilm bacteria are physiologically distinct from free-swimming bacteria of the same species. (asm.org)
  • exhibit
  • Mushroom-shaped biofilm structures, which are reported for many bacteria, exhibit topographically varying levels of multiple drug resistance from the cap of the mushroom to its stalk. (ntu.edu.sg)
  • motility
  • Here we identify a new role for Psl in early biofilm development using a massively parallel cell-tracking algorithm to extract the motility history of every cell on a newly colonized surface. (nih.gov)
  • By combining this technique with fluorescent Psl staining and computer simulations, we show that P. aeruginosa deposits a trail of Psl as it moves on a surface, which influences the surface motility of subsequent cells that encounter these trails and thus generates positive feedback. (nih.gov)
  • respiratory
  • We have observed that respiratory virus coinfection and the antiviral immune response aid in the transition of P . aeruginosa to a biofilm mode of growth through inappropriate release of the nutrient iron. (pnas.org)
  • Biofilms in Pediatric Respiratory and Related Infe. (scribd.com)
  • resistance
  • Despite optimized pharmacokinetic/pharmacodynamic (PK/PD) parameters, CIP treatment did not suppress resistance development in P. aeruginosa biofilms. (dtu.dk)
  • Segregation of bacteria based on their metabolic activities in biofilms plays an important role in the development of antibiotic resistance. (ntu.edu.sg)