Artículos de revistas sobre el tema "Biofilm-detached"
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1
Behnke, Sabrina, Albert E. Parker, Dawn Woodall y 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, n.º 20 (19 de agosto de 2011): 7176–84. http://dx.doi.org/10.1128/aem.05514-11.
Resumen
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.
2
Liu, Jia, Jun-Qi Ling, Kai Zhang, Li-Jun Huo y Yang Ning. "Effect of Sodium Fluoride, Ampicillin, and Chlorhexidine on Streptococcus mutans Biofilm Detachment". Antimicrobial Agents and Chemotherapy 56, n.º 8 (4 de junio de 2012): 4532–35. http://dx.doi.org/10.1128/aac.00885-12.
Resumen
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.
3
Liu, Jia, Jun-Qi Ling, Kai Zhang y Christine D. Wu. "Physiological properties ofStreptococcus mutansUA159 biofilm-detached cells". FEMS Microbiology Letters 340, n.º 1 (14 de enero de 2013): 11–18. http://dx.doi.org/10.1111/1574-6968.12066.
4
Perpetuini, Giorgia, Fabrizia Tittarelli, Carlo Perla y Rosanna Tofalo. "Influence of Different Aggregation States on Volatile Organic Compounds Released by Dairy Kluyveromyces marxianus Strains". Foods 11, n.º 18 (19 de septiembre de 2022): 2910. http://dx.doi.org/10.3390/foods11182910.
Resumen
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.
5
Wilson, Suzanne, Martin A. Hamilton, Gordon C. Hamilton, Margo R. Schumann y 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, n.º 10 (octubre de 2004): 5847–52. http://dx.doi.org/10.1128/aem.70.10.5847-5852.2004.
Resumen
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.
6
Watanabe, Yoshimasa, Chulhee Lee, Makoto Koike y Masayoshi Ishiguro. "Nitrification Kinetics and Simultaneous Removal of Biomass and Phosphorus in Rotating Biological Contactors". Water Science and Technology 22, n.º 3-4 (1 de marzo de 1990): 169–78. http://dx.doi.org/10.2166/wst.1990.0198.
Resumen
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.
7
Bester, Elanna, Gideon Wolfaardt, Lydia Joubert, Kerstin Garny y Sanja Saftic. "Planktonic-Cell Yield of a Pseudomonad Biofilm". Applied and Environmental Microbiology 71, n.º 12 (diciembre de 2005): 7792–98. http://dx.doi.org/10.1128/aem.71.12.7792-7798.2005.
Resumen
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.
8
Hou, Shuyu, Zhigang Liu, Anne W. Young, Sheron L. Mark, Neville R. Kallenbach y 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, n.º 6 (22 de enero de 2010): 1967–74. http://dx.doi.org/10.1128/aem.02321-09.
Resumen
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 y J. W. Costerton. "Growth and Detachment of Cell Clusters from Mature Mixed-Species Biofilms". Applied and Environmental Microbiology 67, n.º 12 (1 de diciembre de 2001): 5608–13. http://dx.doi.org/10.1128/aem.67.12.5608-5613.2001.
Resumen
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.
10
Fux, C. A., S. Wilson y P. Stoodley. "Detachment Characteristics and Oxacillin Resistance of Staphyloccocus aureus Biofilm Emboli in an In Vitro Catheter Infection Model". Journal of Bacteriology 186, n.º 14 (15 de julio de 2004): 4486–91. http://dx.doi.org/10.1128/jb.186.14.4486-4491.2004.
Resumen
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.
11
Coufort, C., N. Derlon, J. Ochoa-Chaves, A. Liné y E. Paul. "Cohesion and detachment in biofilm systems for different electron acceptor and donors". Water Science and Technology 55, n.º 8-9 (1 de abril de 2007): 421–28. http://dx.doi.org/10.2166/wst.2007.286.
Resumen
This work deals with the cohesion and detachment in biofilm systems for two electron acceptors and for two electron donors. Biofilms were developed on plates, under very low shear stress for one month and then subjected to an erosion test for two hours in a Couette-Taylor reactor. Biofilm was characterised in terms of average thickness and residual TOC mass. It was found that the biofilm structure is very heterogeneous and stratified. The top layer, which represents 60% of the biofilm mass, is very fragile and can be easily detached; the basal layer, which represents 20% of the biofilm mass, is very cohesive and can resist shear stresses up to 13 Pa. Between these two layers, a middle layer of intermediary cohesion represents 20% of the initial biofilm mass.
12
Izano, Era A., Matthew A. Amarante, William B. Kher y Jeffrey B. Kaplan. "Differential Roles of Poly-N-Acetylglucosamine Surface Polysaccharide and Extracellular DNA in Staphylococcus aureus and Staphylococcus epidermidis Biofilms". Applied and Environmental Microbiology 74, n.º 2 (26 de noviembre de 2007): 470–76. http://dx.doi.org/10.1128/aem.02073-07.
Resumen
ABSTRACT Staphylococcus aureus and Staphylococcus epidermidis are major human pathogens of increasing importance due to the dissemination of antibiotic-resistant strains. Evidence suggests that the ability to form matrix-encased biofilms contributes to the pathogenesis of S. aureus and S. epidermidis. In this study, we investigated the functions of two staphylococcal biofilm matrix polymers: poly-N-acetylglucosamine surface polysaccharide (PNAG) and extracellular DNA (ecDNA). We measured the ability of a PNAG-degrading enzyme (dispersin B) and DNase I to inhibit biofilm formation, detach preformed biofilms, and sensitize biofilms to killing by the cationic detergent cetylpyridinium chloride (CPC) in a 96-well microtiter plate assay. When added to growth medium, both dispersin B and DNase I inhibited biofilm formation by both S. aureus and S. epidermidis. Dispersin B detached preformed S. epidermidis biofilms but not S. aureus biofilms, whereas DNase I detached S. aureus biofilms but not S. epidermidis biofilms. Similarly, dispersin B sensitized S. epidermidis biofilms to CPC killing, whereas DNase I sensitized S. aureus biofilms to CPC killing. We concluded that PNAG and ecDNA play fundamentally different structural roles in S. aureus and S. epidermidis biofilms.
13
Pouget, Cassandra, Catherine Dunyach-Remy, Chloé Magnan, Alix Pantel, Albert Sotto y Jean-Philippe Lavigne. "Polymicrobial Biofilm Organization of Staphylococcus aureus and Pseudomonas aeruginosa in a Chronic Wound Environment". International Journal of Molecular Sciences 23, n.º 18 (15 de septiembre de 2022): 10761. http://dx.doi.org/10.3390/ijms231810761.
Resumen
Biofilm on the skin surface of chronic wounds is an important step that involves difficulties in wound healing. The polymicrobial nature inside this pathogenic biofilm is key to understanding the chronicity of the lesion. Few in vitro models have been developed to study bacterial interactions inside this chronic wound. We evaluated the biofilm formation and the evolution of bacteria released from this biofilm on the two main bacteria isolated in this condition, Staphylococcus aureus and Pseudomonas aeruginosa, using a dynamic system (BioFlux™ 200) and a chronic wound-like medium (CWM) that mimics the chronic wound environment. We observed that all species constituted a faster biofilm in the CWM compared to a traditional culture medium (p < 0.01). The percentages of biofilm formation were significantly higher in the mixed biofilm compared to those determined for the bacterial species alone (p < 0.01). Biofilm organization was a non-random structure where S. aureus aggregates were located close to the wound surface, whereas P. aeruginosa was located deeper in the wound bed. Planktonic biofilm-detached bacteria showed decreased growth, overexpression of genes encoding biofilm formation, and an increase in the mature biofilm biomass formed. Our data confirmed the impact of the chronic wound environment on biofilm formation and on bacterial lifecycle inside the biofilm.
14
Reichert, Peter y Oskar Wanner. "Movement of solids in biofilms: significance of liquid phase transport". Water Science and Technology 36, n.º 1 (1 de julio de 1997): 321–28. http://dx.doi.org/10.2166/wst.1997.0070.
Resumen
In the one-dimensional mixed-culture biofilm model, volume expansion due to microbial growth leads to a displacement of biomass towards the biofilm surface, where solids (cells and particles) can be detached and attached. In this model there are no suspended solids in the pore volume of the biofilm. In a growing biofilm, this description makes a significant penetration of solids from the bulk fluid into the biofilm impossible and it leads to a fast elimination of attached inert particles from the biofilm. Recent experiments with fluorescent microbeads used as solid tracers are in disagreement with this description. The inert tracer particles added to the bulk fluid penetrate the biofilm quite fast and they show a residence time in the film that is much larger than that of the bacteria. For this reason the processes “transport of solids suspended in the biofilm pore volume” and “attachment to” and “detachment from the solid matrix in the biofilm interior” were added to the mixed-culture biofilm model. These processes were also implemented in the biofilm reactor compartment of the simulation program AQUASIM which is used here to demonstrate that the new processes make a qualitative simulation of the observed behavior possible. Therefore, the mixed-culture biofilm model with these processes added can be used as a tool for further research on the mechanisms which determine the development of the biofilm solid matrix and on transport of solids in the biofilm pore volume.
15
Tajima, Yutaka, Rie Takagi, Tamiko Nakajima, Toshiro Yasuda y Yoshihiko Kominato. "11-Tungstophosphate with Iron(II) and Hydrogen Peroxide Efficiently Detached Bacterial Biofilm". Biological & Pharmaceutical Bulletin 32, n.º 10 (2009): 1783–89. http://dx.doi.org/10.1248/bpb.32.1783.
16
Khu, Soon-Thiam, Changchun Xin, Tianzhi Wang, Ying Zhang y Xin Zuo. "Effects of hydraulic conditions on biofilm detached in drinking water distribution system". Journal of Water Process Engineering 53 (julio de 2023): 103882. http://dx.doi.org/10.1016/j.jwpe.2023.103882.
17
Ohashi, Akiyoshi y Hideki Harada. "A novel concept for evaluation of biofilm adhesion strength by applying tensile force and shear force". Water Science and Technology 34, n.º 5-6 (1 de septiembre de 1996): 201–11. http://dx.doi.org/10.2166/wst.1996.0552.
Resumen
A novel methodology is proposed in this study to evaluate biofilm adhesion strength in two different ways: by measuring detached biomass caused by tensile force and by shear force. Tensile force was provided by centrifuging biofilm-attached plates installed on rotary tables. Shear force was provided by colliding biofilm-attached plates by gravity. Test biofilms consisting of denitrifiers were formed on the flat surfaces of square (25 cm2) plates that had been submerged in a rectangular open-channel reactor. The detachment tests revealed that, although biofilm adhesion strength was relatively high at the earlier growth stage, it drastically decreased at the later stage. The most weakened location toward biofilm depth was observed at the substratum surface, at which the adhesion strength by tensile force dropped from a several Pa to below 1 Pa as biofilms became aged. The adhesion strength by shear force was all the time more than 100 times as large as that by tensile force, even though having a similar behavior. The proportion of cavity, i.e., biofilm-absent area at the biofilm/substratum interface, increased as biofilms became mature. Cavity formation was strongly responsible for lessening the adhesion strength. It is suggested that biofilm slough-off is caused by the decline of adhesion strength by tensile force rather than by shear force.
18
Muñoz, Isabel, Ainhoa Gaudes, Sergi Sabater y Elisabet Vilalta. "The nematode community in cyanobacterial biofilms in the river Llobregat, Spain". Nematology 8, n.º 6 (2006): 909–19. http://dx.doi.org/10.1163/156854106779799169.
Resumen
AbstractThe aim of our study was to understand the role of the nematode community in a cyanobacterial-dominated biofilm located in the river Llobregat, NE Spain. This biofilm was mainly composed of oscillatorial species and diatoms. Fractions of these mats can become detached from the substrata and become free-floating, dispersing downstream and acquiring different structural and physiological properties. Both cyanobacterial biofilms, attached and free-floating, were compared with another benthic biofilm that occurred in the reach of the river that was studied. The nematode diversity was restricted, and was dominated by Chromadorita leuckarti, Diplogaster rivalis, Plectus parvus, Neotobrilus diversipapillatus, Monhystera spp., Dorylaimus sp. and Mononchus sp. Nematode density and biomass were significantly greater in the free-floating biofilm (maximum values of 752 ind/cm2 and 171.3 μgC/cm2). Different trophic and sexual strategies were observed. The free-floating biofilm showed higher abundances of juveniles and a high proportion of gravid females. A positive correlation was observed between cyanobacterial density and the abundance of juveniles or adults of the commonest nematode species, indicating their potential as food resources.
19
Hunt, Stephen M., Erin M. Werner, Baochuan Huang, Martin A. Hamilton y Philip S. Stewart. "Hypothesis for the Role of Nutrient Starvation in Biofilm Detachment". Applied and Environmental Microbiology 70, n.º 12 (diciembre de 2004): 7418–25. http://dx.doi.org/10.1128/aem.70.12.7418-7425.2004.
Resumen
ABSTRACT A combination of experimental and theoretical approaches was used to investigate the role of nutrient starvation as a potential trigger for biofilm detachment. Experimental observations of detachment in a variety of biofilm systems were made with pure cultures of Pseudomonas aeruginosa. These observations indicated that biofilms grown under continuous-flow conditions detached after flow was stopped, that hollow cell clusters were sometimes observed in biofilms grown in flow cells, and that lysed cells were apparent in the internal strata of colony biofilms. When biofilms were nutrient starved under continuous-flow conditions, detachment still occurred, suggesting that starvation and not the accumulation of a metabolic product was responsible for triggering detachment in this particular system. A cellular automata computer model of biofilm dynamics was used to explore the starvation-dependent detachment mechanism. The model predicted biofilm structures and dynamics that were qualitatively similar to those observed experimentally. The predicted features included centrally located voids appearing in sufficiently large cell clusters, gradients in growth rate within these clusters, and the release of most of the biofilm with simulated stopped-flow conditions. The model was also able to predict biofilm sloughing resulting solely from this detachment mechanism. These results support the conjecture that nutrient starvation is an environmental cue for the release of microbes from a biofilm.
20
Steed, Keesha A. y Joseph O. Falkinham. "Effect of Growth in Biofilms on Chlorine Susceptibility of Mycobacterium avium and Mycobacterium intracellulare". Applied and Environmental Microbiology 72, n.º 6 (junio de 2006): 4007–11. http://dx.doi.org/10.1128/aem.02573-05.
Resumen
ABSTRACT Mycobacterium avium and Mycobacterium intracellulare were grown in suspension and in biofilms, and their susceptibilities to chlorine were measured. M. avium and M. intracellulare readily adhered within 2 h, and numbers increased 10-fold in 30 days at room temperature in biofilms on both polystyrene flasks and glass beads. The chlorine resistance of M. avium and M. intracellulare cells grown and exposed to chlorine in biofilms was significantly higher than that of cells grown in suspension. Survival curves showed no evidence of a resistant, persisting population after 6 h of exposure to 1 μg chlorine/ml. The chlorine susceptibility of cells grown in biofilms and exposed in suspension (cells detached from bead surfaces) was also significantly higher than that of cells grown and exposed in suspension (planktonic cells), although it was lower than that of cells grown and exposed in biofilms. The higher resistance of the detached biofilm-grown cells was reversed upon their growth in suspension. There was a strong correlation between the chlorine susceptibility of cells of both M. avium and M. intracellulare and cell surface hydrophobicity measured by contact angle for both biofilm- and suspension-grown cells.
21
Puig, Carmen, Arnau Domenech, Junkal Garmendia, Jeroen D. Langereis, Pascal Mayer, Laura Calatayud, Josefina Liñares, Carmen Ardanuy y Sara Marti. "Increased Biofilm Formation by Nontypeable Haemophilus influenzae Isolates from Patients with Invasive Disease or Otitis Media versus Strains Recovered from Cases of Respiratory Infections". Applied and Environmental Microbiology 80, n.º 22 (5 de septiembre de 2014): 7088–95. http://dx.doi.org/10.1128/aem.02544-14.
Resumen
ABSTRACTBiofilm formation by nontypeable (NT)Haemophilus influenzaeremains a controversial topic. Nevertheless, biofilm-like structures have been observed in the middle-ear mucosa of experimental chinchilla models of otitis media (OM). To date, there have been no studies of biofilm formation in large collections of clinical isolates. This study aimed to investigate the initial adhesion to a solid surface and biofilm formation by NTH. influenzaeby comparing isolates from healthy carriers, those with noninvasive respiratory disease, and those with invasive respiratory disease. We used 352 isolates from patients with nonbacteremic community-acquired pneumonia (NB-CAP), chronic obstructive pulmonary disease (COPD), OM, and invasive disease and a group of healthy colonized children. We then determined the speed of initial adhesion to a solid surface by the BioFilm ring test and quantified biofilm formation by crystal violet staining. Isolates from different clinical sources displayed high levels of biofilm formation on a static solid support after growth for 24 h. We observed clear differences in initial attachment and biofilm formation depending on the pathology associated with NTH. influenzaeisolation, with significantly increased biofilm formation for NTH. influenzaeisolates collected from patients with invasive disease and OM compared with NTH. influenzaeisolates from patients with NB-CAP or COPD and healthy colonized subjects. In all cases, biofilm structures were detached by proteinase K treatment, suggesting an important role for proteins in the initial adhesion and static biofilm formation measured by crystal violet staining.
22
Borucki, Monica K., Jason D. Peppin, David White, Frank Loge y Douglas R. Call. "Variation in Biofilm Formation among Strains of Listeria monocytogenes". Applied and Environmental Microbiology 69, n.º 12 (diciembre de 2003): 7336–42. http://dx.doi.org/10.1128/aem.69.12.7336-7342.2003.
Resumen
ABSTRACT Contamination of food by Listeria monocytogenes is thought to occur most frequently in food-processing environments where cells persist due to their ability to attach to stainless steel and other surfaces. Once attached these cells may produce multicellular biofilms that are resistant to disinfection and from which cells can become detached and contaminate food products. Because there is a correlation between virulence and serotype (and thus phylogenetic division) of L. monocytogenes, it is important to determine if there is a link between biofilm formation and disease incidence for L. monocytogenes. Eighty L. monocytogenes isolates were screened for biofilm formation to determine if there is a robust relationship between biofilm formation, phylogenic division, and persistence in the environment. Statistically significant differences were detected between phylogenetic divisions. Increased biofilm formation was observed in Division II strains (serotypes 1/2a and 1/2c), which are not normally associated with food-borne outbreaks. Differences in biofilm formation were also detected between persistent and nonpersistent strains isolated from bulk milk samples, with persistent strains showing increased biofilm formation relative to nonpersistent strains. There were no significant differences detected among serotypes. Exopolysaccharide production correlated with cell adherence for high-biofilm-producing strains. Scanning electron microscopy showed that a high-biofilm-forming strain produced a dense, three-dimensional structure, whereas a low-biofilm-forming strain produced a thin, patchy biofilm. These data are consistent with data on persistent strains forming biofilms but do not support a consistent relationship between enhanced biofilm formation and disease incidence.
23
KHELISSA, SIMON OUSSAMA, MARWAN ABDALLAH, CHARAFEDDINE JAMA, ALEXANDRE BARRAS y NOUR-EDDINE CHIHIB. "Comparative Study on the Impact of Growth Conditions on the Physiology and the Virulence of Pseudomonas aeruginosa Biofilm and Planktonic Cells". Journal of Food Protection 82, n.º 8 (17 de julio de 2019): 1357–63. http://dx.doi.org/10.4315/0362-028x.jfp-18-565.
Resumen
ABSTRACT The aim of the present work was to study and compare the effect of growth temperature (20, 30, and 37°C) and surface type (stainless steel and polycarbonate) on the production of virulence factors, such as proteases and siderophores, and the risk of surface contamination associated with Pseudomonas aeruginosa biofilm and planktonic cells. The increase of growth temperature from 20 to 37°C increased (approximately twofold) the electronegative charge and the hydrophobicity of the P. aeruginosa biofilm cell surface. P. aeruginosa biofilm cell adhesion to stainless steel and polycarbonate was 5- and 1.5-fold higher than their planktonic counterparts at 20 and 30°C, respectively. The increase of growth temperature from 20 to 37°C increased the production of proteases (twofold) and siderophores (twofold) and the cytotoxicity (up to 30-fold) against the HeLa cell line in the supernatants of P. aeruginosa planktonic and biofilm cultures. This study also highlighted that biofilm and planktonic P. aeruginosa cells exhibited distinct physiological properties with respect to the production of virulence factors and the cytotoxicity against the Hela cell line. Therefore, effective disinfection procedures should be adapted to inactivate bacteria detached from biofilms.
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Hay, Amanda J. y Jun Zhu. "Host Intestinal Signal-Promoted Biofilm Dispersal Induces Vibrio cholerae Colonization". Infection and Immunity 83, n.º 1 (3 de noviembre de 2014): 317–23. http://dx.doi.org/10.1128/iai.02617-14.
Resumen
Vibrio choleraecauses human infection through ingestion of contaminated food and water, leading to the devastating diarrheal disease cholera.V. choleraeforms matrix-encased aggregates, known as biofilms, in the native aquatic environment. While the formation ofV. choleraebiofilms has been well studied, little is known about the dispersal from biofilms, particularly upon entry into the host. In this study, we found that the exposure of mature biofilms to physiologic levels of the bile salt taurocholate, a host signal for the virulence gene induction ofV. cholerae, induces an increase in the number of detached cells with a concomitant decrease in biofilm mass. Scanning electron microscopy micrographs of biofilms exposed to taurocholate revealed an altered, perhaps degraded, appearance of the biofilm matrix. The inhibition of protein synthesis did not alter rates of detachment, suggesting thatV. choleraeundergoes a passive dispersal. Cell-free media from taurocholate-exposed biofilms contains a larger amount of free polysaccharide, suggesting an abiotic degradation of biofilm matrix by taurocholate. Furthermore, we found thatV. choleraeis only able to induce virulence in response to taurocholate after exit from the biofilm. Thus, we propose a model in whichV. choleraeingested as a biofilm has coopted the host-derived bile salt signal to detach from the biofilm and go on to activate virulence.
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Xue, Zheng, Varun Raj Sendamangalam, Cyndee L. Gruden y Youngwoo Seo. "Multiple Roles of Extracellular Polymeric Substances on Resistance of Biofilm and Detached Clusters". Environmental Science & Technology 46, n.º 24 (3 de diciembre de 2012): 13212–19. http://dx.doi.org/10.1021/es3031165.
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Sheldon, Jessica R., Mi-Sung Yim, Jessica H. Saliba, Wai-Hong Chung, Kwok-Yin Wong y Kam Tin Leung. "Role ofrpoSin Escherichia coli O157:H7 Strain H32 Biofilm Development and Survival". Applied and Environmental Microbiology 78, n.º 23 (21 de septiembre de 2012): 8331–39. http://dx.doi.org/10.1128/aem.02149-12.
Resumen
ABSTRACTThe protein RpoS is responsible for mediating cell survival during the stationary phase by conferring cell resistance to various stressors and has been linked to biofilm formation. In this study, the role of therpoSgene inEscherichia coliO157:H7 biofilm formation and survival in water was investigated. Confocal scanning laser microscopy of biofilms established on coverslips revealed a nutrient-dependent role ofrpoSin biofilm formation, where the biofilm biomass volume of therpoSmutant was 2.4- to 7.5-fold the size of itsrpoS+wild-type counterpart in minimal growth medium. The enhanced biofilm formation of therpoSmutant did not, however, translate to increased survival in sterile double-distilled water (ddH2O), filter-sterilized lake water, or unfiltered lake water. TherpoSmutant had an overall reduction of 3.10 and 5.30 log10in sterile ddH2O and filter-sterilized lake water, respectively, while only minor reductions of 0.53 and 0.61 log10in viable counts were observed for the wild-type form in the two media over a 13-day period, respectively. However, the survival rates of the detached biofilm-derivedrpoS+andrpoSmutant cells were comparable. Under the competitive stress conditions of unfiltered lake water, the advantage conferred by the presence ofrpoSwas lost, and both the wild-type and knockout forms displayed similar declines in viable counts. These results suggest thatrpoSdoes have an influence on both biofilm formation and survival ofE. coliO157:H7 and that the advantage conferred byrpoSis contingent on the environmental conditions.
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Porteous, Nuala, Jie Luo, Monica Hererra, John Schoolfield y Yuyu Sun. "Growth and Identification of Bacteria inN-Halamine Dental Unit Waterline Tubing Using an Ultrapure Water Source". International Journal of Microbiology 2011 (2011): 1–6. http://dx.doi.org/10.1155/2011/767314.
Resumen
This study examined bacterial growth and type on biofilm-controlling dental unit waterline (DUWL) tubing (T) and control manufacturer's tubing (C) in a laboratory DUWL model using ultrapure source water that was cycled through the lines. Sections of tubing lines were detached and examined for biofilm growth using SEM imaging at six sampling periods. Bacteria from inside surfaces of T and C, source unit, and reservoir were cultured and enumerated. At six months, organisms were molecularly identified from the alignment matches obtained from the top three BLAST searches for the 16S region. There was a 1–3 log increase in organism growth in a clean, nonsterile reservoir within an hour. Biofilm was established on the inside surfaces of C within three weeks, but not on T.Proteobacteria, andSphingomonasspp. were identified in the source reservoir and C line, and a variation of the genera was found in T line.
28
Eisenmann, Heinrich, Ioanna Letsiou, Anette Feuchtinger, Wolfgang Beisker, Ernst Mannweiler, Peter Hutzler y Patrik Arnz. "Interception of Small Particles by Flocculent Structures, Sessile Ciliates, and the Basic Layer of a Wastewater Biofilm". Applied and Environmental Microbiology 67, n.º 9 (1 de septiembre de 2001): 4286–92. http://dx.doi.org/10.1128/aem.67.9.4286-4292.2001.
Resumen
ABSTRACT We investigated attachment processes of hydrophobic and hydrophilic particles (diameter = 1 μm) to mature biofilms grown on clay marbles in a sequencing batch biofilm reactor. During a treatment cycle with filtered wastewater containing different fluorescent beads, the progression of particle density in various biofilm compartments (carrier biofilm, basic biofilm layer, biofilm flocs, and sessile ciliates) was determined by flow cytometry, confocal laser scanning microscopy and automated image analysis. Particles were almost completely removed from wastewater by typical processes of particle retention: up to 58% of particles attached to clay marbles, up to 15% were associated with suspended flocs, and up to 10% were ingested by sessile ciliates. Ingestion of particles by ciliates was exceptionally high immediately after wastewater addition (1,200 particles grazer−1 h−1) and continued until approximately 14% of the water had been cleared by ciliate filter feeding. Most probably, ciliate bioturbation increases particle sorption to the basic biofilm. Backwashing of the reactor detached pieces of biofilm and thus released approximately 50% of the particles into rinsing water. Clay marbles in the upper part of the reactor were more efficiently abraded than in the lower part. No indications for selective attachment of the applied hydrophobic and hydrophilic beads were found. As a consequence of interception patterns, organisms at elevated biofilm structures are probably major profiteers of wastewater particles; among them, ciliates may be of major importance because of their highly active digestive food vacuoles.
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Simões, Lúcia Chaves y Manuel Simões. "Contribution to Understanding the Mechanisms Involved in Biofilm Formation, Tolerance and Control". International Journal of Molecular Sciences 24, n.º 11 (30 de mayo de 2023): 9475. http://dx.doi.org/10.3390/ijms24119475.
Resumen
Biofilms constitute a protected mode of growth that allows the colonizing microbial cells to survive in hostile environments, even when an antimicrobial agent is present. The scientific community has come to understand many things about the growth dynamics and behavior of microbial biofilms. It is now accepted that biofilm formation is a multifactorial process that starts with the adhesion of individual cells and (auto-)coaggregates of cells to a surface. Then, attached cells grow, reproduce and secrete insoluble extracellular polymeric substances. As the biofilm matures, biofilm detachment and growth processes come into balance, such that the total amount of biomass on the surface remains approximately constant in time. The detached cells retain the phenotype of the biofilm cells, which facilitates the colonization of neighboring surfaces. The most common practice to eliminate unwanted biofilms is the application of antimicrobial agents. However, conventional antimicrobial agents often show inefficacy in the control of biofilms. Much remains to be understood in the biofilm formation process and in the development of effective strategies for biofilm prevention and control. The articles contained in this Special Issue deal with biofilms of some important bacteria (including pathogens such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus) and fungi (Candida tropicalis), providing novel insights into their formation mechanisms and implications, together with novel methods (e.g., use of chemical conjugates and combinations of molecules) that can be used to disrupt the biofilm structure and kill the colonizing cells.
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Chandra, Jyotsna, Jasmine D. Patel, Jian Li, Guangyin Zhou, Pranab K. Mukherjee, Thomas S. McCormick, James M. Anderson y Mahmoud A. Ghannoum. "Modification of Surface Properties of Biomaterials Influences the Ability of Candida albicans To Form Biofilms". Applied and Environmental Microbiology 71, n.º 12 (diciembre de 2005): 8795–801. http://dx.doi.org/10.1128/aem.71.12.8795-8801.2005.
Resumen
ABSTRACT Candida albicans biofilms form on indwelling medical devices (e.g., denture acrylic or intravenous catheters) and are associated with both oral and invasive candidiasis. Here, we determined whether surface modifications of polyetherurethane (Elasthane 80A [E80A]), polycarbonateurethane, and poly(ethyleneterephthalate) (PET) can influence fungal biofilm formation. Polyurethanes were modified by adding 6% polyethylene oxide (6PEO), 6% fluorocarbon, or silicone, while the PET surface was modified to generate hydrophilic, hydrophobic, cationic, or anionic surfaces. Formation of biofilm was quantified by determining metabolic activity and total biomass (dry weight), while its architecture was analyzed by confocal scanning laser microscopy (CSLM). The metabolic activity of biofilm formed by C. albicans on 6PEO-E80A was significantly reduced (by 78%) compared to that of biofilm formed on the nonmodified E80A (optical densities of 0.054 ± 0.020 and 0.24 ± 0.10, respectively; P = 0.037). The total biomass of Candida biofilm formed on 6PEO-E80A was 74% lower than that on the nonmodified E80A surface (0.46 ± 0.15 versus 1.76 ± 0.32 mg, respectively; P = 0.003). Fungal cells were easily detached from the 6PEO-E80A surface, and we were unable to detect C. albicans biofilm on this surface by CSLM. All other surface modifications allowed formation of C. albicans biofilm, with some differences in thearchitecture. Correlation between contact angle and biofilm formation was observed for polyetherurethane substrates (r = 0.88) but not for PET biomaterials (r = −0.40). This study illustrates that surface modification is a viable approach for identifying surfaces that have antibiofilm characteristics. Investigations into the clinical utility of the identified surfaces are warranted.
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Behnke, Sabrina y Anne K. Camper. "Chlorine dioxide disinfection of single and dual species biofilms, detached biofilm and planktonic cells". Biofouling 28, n.º 6 (27 de junio de 2012): 635–47. http://dx.doi.org/10.1080/08927014.2012.700705.
32
Khelissa, Simon Oussama, Marwan Abdallah, Charafeddine Jama y Nour-Eddine Chihib. "Actively detached Pseudomonas aeruginosa biofilm cell susceptibility to benzalkonium chloride and associated resistance mechanism". Archives of Microbiology 201, n.º 6 (5 de marzo de 2019): 747–55. http://dx.doi.org/10.1007/s00203-019-01643-x.
33
Aqeel, Hussain y Steven N. Liss. "Fate of sloughed biomass in integrated fixed-film systems". PLOS ONE 17, n.º 1 (21 de enero de 2022): e0262603. http://dx.doi.org/10.1371/journal.pone.0262603.
Resumen
Fate of biofilm sloughing was assessed in a laboratory-scale (LS) integrated fixed-film sequencing batch reactor (IF-SBR) treating synthetic wastewater and in a full-scale (FS) integrated fixed-film activated sludge (IFAS) system treating municipal wastewater. It was observed that the properties of biofilms and flocs, including sludge volume index (SVI), mixed liquor suspended solids (MLSS), effluent suspended solids (ESS), relative hydrophobicity, and composition of extracellular polymeric substance (EPS) were associated with biofilm sloughing and formation of large granular flocs in the LS IF–SBR. In the FS IFAS system, the changes were studied at the molecular level. For example, the extracted EPS content results (the protein to polysaccharide ratio decreased in the flocs and increased in the biofilms, with biofilm sloughing) were complemented with the confocal laser scanning microscopy (CLSM) coupled with molecular specific staining. CLSM analyses revealed that micro-colonies rich in polysaccharides readily sloughed from the carriers. Live-dead staining revealed areas of the biofilm where the viability of biomass was a contributing factor associated with areas of the biofilm susceptible to sloughing. 16S rRNA gene sequencing (Illumina) of FS IFAS samples revealed greater diversity (α-diversity) in biofilms compared to flocs. Biofilm sloughing resulted in a decrease in diversity in biofilms and a corresponding increase in the flocs during sloughing. Microbial population dynamics revealed that bacteria known for denitrification (for example, Comamonadaceae) detached from the biofilms during sloughing, readily associated with the suspended biomass, and were retained in the bioreactors.
34
WANG, RONG, JAMES L. BONO, NORASAK KALCHAYANAND, STEVEN SHACKELFORD y DAYNA M. HARHAY. "Biofilm Formation by Shiga Toxin–Producing Escherichia coli O157:H7 and Non-O157 Strains and Their Tolerance to Sanitizers Commonly Used in the Food Processing Environment†". Journal of Food Protection 75, n.º 8 (1 de agosto de 2012): 1418–28. http://dx.doi.org/10.4315/0362-028x.jfp-11-427.
Resumen
Shiga toxin–producing Escherichia coli (STEC) strains are important foodborne pathogens. Among these, E. coli O157:H7 is the most frequently isolated STEC serotype responsible for foodborne diseases. However, the non-O157 serotypes have been associated with serious outbreaks and sporadic diseases as well. It has been shown that various STEC serotypes are capable of forming biofilms on different food or food contact surfaces that, when detached, may lead to cross-contamination. Bacterial cells at biofilm stage also are more tolerant to sanitizers compared with their planktonic counterparts, which makes STEC biofilms a serious food safety concern. In the present study, we evaluated the potency of biofilm formation by a variety of STEC strains from serotypes O157:H7, O26:H11, and O111:H8; we also compared biofilm tolerance with two types of common sanitizers, a quaternary ammonium chloride–based sanitizer and chlorine. Our results demonstrated that biofilm formation by various STEC serotypes on a polystyrene surface was highly strain-dependent, whereas the two non-O157 serotypes showed a higher potency of pellicle formation at air-liquid interfaces on a glass surface compared with serotype O157:H7. Significant reductions of viable biofilm cells were achieved with sanitizer treatments. STEC biofilm tolerance to sanitization was strain-dependent regardless of the serotypes. Curli expression appeared to play a critical role in STEC biofilm formation and tolerance to sanitizers. Our data indicated that multiple factors, including bacterial serotype and strain, surface materials, and other environmental conditions, could significantly affect STEC biofilm formation. The high potential for biofilm formation by various STEC serotypes, especially the strong potency of pellicle formation by the curli-positive non-O157 strains with high sanitization tolerance, might contribute to bacterial colonization on food contact surfaces, which may result in downstream product contamination.
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Moerke, Caroline, Marlen Kloss, Katharina Wulf, Sabine Illner, Sabine Kischkel, Martina Sombetzki, Niels Grabow, Emil Reisinger, Alper Öner y Hüseyin Ince. "Evaluation of a Murine Model for Testing Antimicrobial Implant Materials in the Blood Circulation System". Biomedicines 9, n.º 10 (13 de octubre de 2021): 1464. http://dx.doi.org/10.3390/biomedicines9101464.
Resumen
Medical device-related infections are becoming a steadily increasing challenge for the health care system regarding the difficulties in the clinical treatment. In particular, cardiovascular implant infections, catheter-related infections, as well as infective endocarditis are associated with high morbidity and mortality risks for the patients. Antimicrobial materials may help to prevent medical device-associated infections and supplement the currently available therapies. In this study, we present an easy-to-handle and simplified in vivo model to test antimicrobial materials in the bloodstream of mice. The model system is composed of the implantation of a bacteria-laden micro-stent scaffold into the murine tail vein. Our model enables the simulation of catheter-related infections as well as the development of infective endocarditis specific pathologies in combination with material testing. Furthermore, this in vivo model can cover two phases of the biofilm formation, including both the local tissue response to the bacterial biofilm and the systemic inflammatory response against circulating bacteria in the bloodstream that detached from a mature biofilm.
36
Storey, M. V. y N. J. Ashbolt. "Persistence of two model enteric viruses (B40-8 and MS-2 bacteriophages) in water distribution pipe biofilms". Water Science and Technology 43, n.º 12 (1 de junio de 2001): 133–38. http://dx.doi.org/10.2166/wst.2001.0724.
Resumen
The persistence of two model enteric virions (Bacteroides fragilis phage B40-8 and coliphage MS-2) within pipe biofilms was investigated in situ in an urban distribution system. Biofilms were allowed to develop on uPVC and stainless steel (SS) coupons in a modified Robbins' device for 70 d within a 150 mm uPVC reticulation main. Coupons were then placed in annular reactors and slug dosed with B40-8 and MS-2 phages (108 pfu/mL). Pipe water velocity, pH and free chlorine were recorded during the experimental period. Biofilms on uPVC were generally more abundant (based on total bacterial counts, HPCs, total protein and total carbohydrate). Both B40-8 and MS-2 were incorporated into biofilms formed on uPVC and SS coupons (>104 and >103 pfu/μg protein respectively) and persisted for >30 d and 6 d respectively, reflecting biofilm biomass on the two pipe surfaces. Virion loss/inactivation from biofilm followed an initial rapid phase, followed by a very slow phase representing approximately 0.01% of the original virion population. Virions, therefore, have the potential to accumulate within distribution biofilm and problems could arise when clusters of biofilm-associated enteric virions become detached from the substrata by hydrodynamic forces or sudden changes in disinfection regime.
37
Wang, Chao, Lingzhan Miao, Jun Hou, Peifang Wang, Jin Qian y Shanshan Dai. "The effect of flow velocity on the distribution and composition of extracellular polymeric substances in biofilms and the detachment mechanism of biofilms". Water Science and Technology 69, n.º 4 (13 de diciembre de 2013): 825–32. http://dx.doi.org/10.2166/wst.2013.785.
Resumen
Flume experiments were conducted to investigate the distribution and composition of extracellular polymeric substances (EPS) in biofilms and the detachment mechanism of biofilms grown under different flow velocity conditions. The results of biofilm growth kinetics showed that the growth trends were coincident with the logistic growth model. The growth kinetics parameters reached their maximum under intermediate velocity (IV) condition. Biofilms exhibited different profiles of EPS composition and distribution, depending on the flow conditions in which the biofilms were grown. The amounts of total polysaccharide and total protein in the thin biofilm (high velocity condition 2 – HV2) were both generally greater than those in the thick biofilm (IV). As compared to the heterogeneous distribution of EPS in the thick biofilms (IV), the EPS in the thin biofilms (HV2) exhibited more homogeneous distribution, and the bound EPS in the thin biofilms (HV2) were much greater than those in the thick biofilms (IV). From the detachment tests, an inverse relationship was observed between the proportion of detached biomass and the value of flow velocity during growth. Biofilms grown under higher velocities showed stronger cohesion than those grown under lower velocities. Therefore, water velocity during biofilm growth conditioned the distribution and composition of EPS, as well as its detachment characteristics under higher shear stress.
38
Papciak, Dorota, Andżelika Domoń, Monika Zdeb, Barbara Tchórzewska-Cieślak, Janusz Konkol y Eleonora Sočo. "Mechanism of Biofilm Formation on Installation Materials and Its Impact on the Quality of Tap Water". Water 14, n.º 15 (2 de agosto de 2022): 2401. http://dx.doi.org/10.3390/w14152401.
Resumen
In the conducted study, an attempt was made to verify and evaluate the impact of the biofilm formed on the surfaces of the installation material on the quality and sanitary safety of tap water reaching the consumer. For biofilm studies, fractal analysis and quantitative bacteriological analysis were used. The quality of tap water flowing through the experimental installation (semi-technical scale) was determined using physicochemical and microbiological parameters. The quantitative analysis of the biofilm showed that an increase in the number of microorganisms was observed in the initial phase of biofilm formation (reached 1.4 × 104 CFU/mL/cm2 on day 14). During this period, there was a chaotic build-up of bacterial cells, as evidenced by an increase in the roughness of the profile lines. Unstable elevations of the biofilm formed in this way could be easily detached from the structure of the material, which resulted in deterioration of the bacteriological quality of the water leaving the installation. The obtained results indicate that the biofilm completely and permanently covered the surface of the tested material after 25 days of testing (the surface roughness described by the fractal dimension decreased). Moreover, the favorable temperature (22.6 °C) and the recorded decrease in the content of inorganic nitrogen (by 15%), phosphorus (by 14%), and dissolved oxygen (by 15%) confirm the activity of microorganisms. The favorable environmental conditions in the installation (the presence of nutrients, low chlorine concentration, and high temperature) contributed to the secondary development of microorganisms, including pathogenic organisms in the tested waters.
39
Gatina, Alina, Elena Trizna, Alena Kolesnikova, Diana Baidamshina, Anna Gorshkova, Valentin Drucker, Mikhail Bogachev y Airat Kayumov. "The Bovhyaluronidase Azoximer (Longidaza®) Disrupts Candida albicans and Candida albicans-Bacterial Mixed Biofilms and Increases the Efficacy of Antifungals". Medicina 58, n.º 12 (23 de noviembre de 2022): 1710. http://dx.doi.org/10.3390/medicina58121710.
Resumen
Background and Objectives: Candida albicans causes various diseases ranging from superficial mycoses to life-threatening systemic infections often associated with biofilm formation, including mixed fungal–bacterial consortia. The biofilm matrix protects cells, making Candida extremely resistant to treatment. Here, we show that the bovhyaluronidase azoximer (Longidaza®) in vitro destroys the biofilm formed by either C. albicans alone or mixed with bacteria, this way decreasing the concentrations of antimicrobials required for the pathogen’s eradication. Materials and Methods: Bovhyaluronidase azoximer, Longidaza® was obtained from NPO Petrovax Pharm Ltd., Moscow, Russia as lyophilized powder. The antifungal activity was assessed by microdilution assay and CFUs counting. Antibiofilm activity was evaluated via biofilms staining and scanning electron microscopy. Results: Thus, treatment with Longidaza® reduced the biofilm biomass of nine C. albicans clinical isolates by 30–60%, while mixed biofilms of C. albicans with various bacteria were destroyed by 30–40%. Furthermore, the concentration of fluconazole required to achieve a similar reduction of the residual respiratory activity of detached cell clumps of four C. albicans isolates has been reduced four-fold when combined with Longidaza®. While in the biofilm, two of four isolates became significantly more susceptible to fluconazole in combination with Longidaza®. Conclusion: Taken together, our data indicate that Longidaza® is capable of suppression of tissues and artificial surfaces biofouling by C. albicans biofilms, as well as facilitating drug penetration into the cell clumps, this way decreasing the effective MIC of antifungals.
40
Mironova, Anna V., Agniya V. Karimova, Mikhail I. Bogachev, Airat R. Kayumov y Elena Y. Trizna. "Alterations in Antibiotic Susceptibility of Staphylococcus aureus and Klebsiella pneumoniae in Dual Species Biofilms". International Journal of Molecular Sciences 24, n.º 10 (9 de mayo de 2023): 8475. http://dx.doi.org/10.3390/ijms24108475.
Resumen
In the last decades, it has been shown that biofilm-associated infections in most cases are caused by rather two or even more pathogens than by single microorganisms. Due to intermicrobial interactions in mixed communities, bacteria change their gene expression profile, in turn leading to alterations in the biofilm structure and properties, as well as susceptibility to antimicrobials. Here, we report the alterations of antimicrobials efficiency in mixed biofilms of Staphylococcus aureus–Klebsiella pneumoniae in comparison with mono-species biofilms of each counterpart and discuss possible mechanisms of these alterations. In cell clumps detached from dual-species biofilms, S. aureus became insensitive to vancomycin, ampicillin, and ceftazidime compared to solely S. aureus cell clumps. In turn, the increased efficiency of amikacin and ciprofloxacin against both bacteria could be observed, compared to mono-species biofilms of each counterpart. Scanning electron microscopy and confocal microscopy indicate the porous structure of the dual-species biofilm, and differential fluorescent staining revealed an increased number of polysaccharides in the matrix, in turn leading to more loose structure and thus apparently providing increased permeability of the dual-species biofilm to antimicrobials. The qRT-PCR showed that ica operon in S. aureus became repressed in mixed communities, and polysaccharides are produced mainly by K. pneumoniae. While the molecular trigger of these changes remains undiscovered, detailed knowledge of the alterations in antibiotic susceptibility to given drugs opens doors for treatment correction options for S. aureus–K. pneumoniae biofilm-associated infections.
41
Zhang, Lingling, Changqing Zhu, Xiaojing Chen, Xinglian Xu y Huhu Wang. "Resistance of detached-cells of biofilm formed by Staphylococcus aureus to ultra high pressure homogenization". Food Research International 139 (enero de 2021): 109954. http://dx.doi.org/10.1016/j.foodres.2020.109954.
42
Alipour, Misagh, Abdelwahab Omri y Zacharias E. Suntres. "Ginseng aqueous extract attenuates the production of virulence factors, stimulates twitching and adhesion, and eradicates biofilms of Pseudomonas aeruginosa". Canadian Journal of Physiology and Pharmacology 89, n.º 6 (junio de 2011): 419–27. http://dx.doi.org/10.1139/y11-057.
Resumen
This study was carried out to examine the antimicrobial activity of the aqueous extract of Panax quinquefolius from North American ginseng (NAGE) root against Pseudomonas aeruginosa . The minimum inhibitory concentrations of reference and clinical isolates of Pseudomonas aeruginosa were measured by a standard agar-dilution method. At subinhibitory NAGE concentrations, the secretion of virulence factors, motility on agar, and adhesion to 96-well microplates were studied on the nonmucoid Pseudomonas aeruginosa O1 strain. At suprainhibitory concentrations, the activity of NAGE against mature biofilm complexes formed in the Calgary Biofilm Device and the Stovall flow cell were assessed. NAGE possessed an antibacterial activity against all the Pseudomonas aeruginosa strains at 1.25%–2.5% w/v. NAGE also significantly attenuated pyocyanin, pyoverdine, and lipase concentrations, stimulated twitching, and attenuated swarming and swimming motility. At 1.25% w/v, NAGE augmented adhesion, and at 5% w/v detached 1-day-old biofilms in microplates. The extract also eradicated 6-day-old mature biofilms (5% w/v), and fluorescence microscopy displayed a reduction of live cells and biofilm complexes compared with nontreated biofilms. These data suggest that the aqueous extract from North American ginseng possesses antimicrobial activities in vitro.
43
Georgiev, Kostadin G., Ivan A. Filipov y Iliyan N. Dobrev. "In Vivo Collection and SEM Identification of Oral Biofilm Using Indirect Composite Prototype Restorations. Clinical and Laboratory Study". Folia Medica 60, n.º 2 (1 de junio de 2018): 300–307. http://dx.doi.org/10.1515/folmed-2017-0092.
Resumen
Abstract Background: The oral ecosystem is a dynamic environment inhabited by more than 700 microbial taxa. Recent studies report that multispecies oral biofilms develop on the surface of resin composites leading to degradation of its organic matrix and altered structural stability of the restoration. Aim: To examine the efficacy of a novel clinical approach to investigating in vivo formed biofilms on resin composite surfaces. Materials and methods: The clinical protocol of this study implemented indirect composite molar restorations (from resin material Filtek Z250, 3M ESPE) as intraoral biofilm carriers (test devices). We recruited for the experiment 5 consenting adult subjects with indications for indirect molar restoration. For each subject we fabricated 4 indirect restorations, 3 of which dedicated to different intraoral duration – 3, 7, and 14 days. All composite carriers were fixed temporarily for the intended time period and consecutively replaced. The detached carriers were prepared for microscope analysis at each time interval. The fourth composite carrier was used as the definitive restoration. Results: The timeline of the biofilm formation and the microbial morphology were associated with previous studies of in vivo bacterial colonisation. A correlation between the plaque formation cycle and the DMFt indices of the subjects was established. Conclusions: The implementation of indirect composite restorations as intraoral biofilm carrier offers valuable contribution to the real time investigation of in vivo biofilm accumulation.
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Simões, M., S. Cleto, M. O. Pereira y M. J. Vieira. "Influence of biofilm composition on the resistance to detachment". Water Science and Technology 55, n.º 8-9 (1 de abril de 2007): 473–80. http://dx.doi.org/10.2166/wst.2007.293.
Resumen
Bacillus cereus and Pseudomonas fluorescens were used to develop monoculture biofilms in a bioreactor rotating system using a stainless steel cylinder for biofilm formation. The biofilms were allowed to grow for 7 days, exposed continuously to a Reynolds number of agitation (ReA) of 2,400. Afterwards, the biofilms were characterised in terms of respiratory activity, amount of biomass, cellular density, cellular size and total and extracellular proteins and polysaccharides. The biofilm mechanical stability was assessed by sequential submission of the biofilms to increasing ReA, respectively, 4,000, 8,100, 12,100 and 16,100. The results showed that P. fluorescens biofilms were five times more active, had a higher amount of biomass, cellular density, a reduced cellular size and a four-fold higher amount of extracellular proteins and polysaccharides than B. cereus biofilms. The application of shear stress forces higher than the one under which the biofilm was formed (ReA=2,400) caused biomass removal. The high percentage of removal occurred with the implementation of a ReA of 8,100 for both B. cereus and P. fluorescens biofilms. The total series of ReA did not give rise to total biofilm removal, as only about 76% of P. fluorescens biofilm mass and 53% of B. cereus biofilm mass were detached from the cylinders. This latter result evidences that B. cereus had a higher mechanical stability than P. fluorescens biofilms. The overall results demonstrate that P. fluorescens and B. cereus formed physiologically distinct biofilms, B. cereus biofilms mainly being constituted by cells and P. fluorescens biofilms largely constituted by extracellular proteins and polysaccharides. B. cereus biofilms had a substantially higher mechanical stability than P. fluorescens biofilms.
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González, C., J. Marciniak, S. Villaverde, C. León, P. A. García y R. Muñoz. "Efficient nutrient removal from swine manure in a tubular biofilm photo-bioreactor using algae-bacteria consortia". Water Science and Technology 58, n.º 1 (1 de julio de 2008): 95–102. http://dx.doi.org/10.2166/wst.2008.655.
Resumen
Concentrated animals feeding operations (CAFOs) often pose a negative environmental impact due to the uncontrolled spreading of manure into soils that ends up in the release of organic matter and nutrients into water bodies. Conventional aerobic methods treating CAFOs wastewater require intensive oxygenation, which significantly increases the operational costs. The alternative proposed in this research is the application of micro-algae based systems by taking advantage of the cost-effective in situ oxygenation via photosynthesis. A 4.9 L enclosed tubular biofilm photo-bioreactor was inoculated with an algal–bacterial consortium formed by the micro-algae Chlorella sorokiniana and a mixed bacterial culture from an activated sludge process. C. sorokiniana delivers the O2 necessary to accomplish both organic matter and ammoniun oxidation. The reactor was fed with diluted swine wastewater containing 180, 15 and 2,000 mg/L of NH4+-N, soluble P and total COD, respectively. The photo-bioreactor exhibited good and sustained nutrient removal efficiencies (up to 99% and 86% for NH4+ and PO43−, respectively) while total COD was removed up to 75% when the biofilm was properly established. Liquid superficial velocities up to 0.4 m/s (achieved by culture broth recirculation) hindered the formation of a stable biofilm, while operation at velocities lower than 0.1 m/s supported stable process performance. The high shear stress imposed by the centrifugal recirculation pump disintegrated the large aggregates detached from the biofilm, which resulted in a poor settling performance and therefore poor COD removal efficiencies. Enclosed biofilm photo-bioreactors therefore offer a potentially more economical alternative to conventional tertiary treatments process.
46
Fong, Jiunn C. N. y Fitnat H. Yildiz. "The rbmBCDEF Gene Cluster Modulates Development of Rugose Colony Morphology and Biofilm Formation in Vibrio cholerae". Journal of Bacteriology 189, n.º 6 (12 de enero de 2007): 2319–30. http://dx.doi.org/10.1128/jb.01569-06.
Resumen
ABSTRACT Vibrio cholerae, the causative agent of cholera, can undergo phenotypic variation generating rugose and smooth variants. The rugose variant forms corrugated colonies and well-developed biofilms and exhibits increased levels of resistance to several environmental stresses. Many of these phenotypes are mediated in part by increased expression of the vps genes, which are organized into vps-I and vps-II coding regions, separated by an intergenic region. In this study, we generated in-frame deletions of the five genes located in the vps intergenic region, termed rbmB to -F (rugosity and biofilm structure modulators B to F) in the rugose genetic background, and characterized the mutants for rugose colony development and biofilm formation. Deletion of rbmB, which encodes a protein with low sequence similarity to polysaccharide hydrolases, resulted in an increase in colony corrugation and accumulation of exopolysaccharides relative to the rugose variant. RbmC and its homolog Bap1 are predicted to encode proteins with carbohydrate-binding domains. The colonies of the rbmC bap1 double deletion mutant and bap1 single deletion mutant exhibited a decrease in colony corrugation. Furthermore, the rbmC bap1 double deletion mutant was unable to form biofilms at the air-liquid interface after 2 days, while the biofilms formed on solid surfaces detached readily. Although the colony morphology of rbmDEF mutants was similar to that of the rugose variant, their biofilm structure and cell aggregation phenotypes were different than those of the rugose variant. Taken together, these results indicate that vps intergenic region genes encode proteins that are involved in biofilm matrix production and maintenance of biofilm structure and stability.
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Hayer, Jason J., Celine Heinemann, Simone M. Schmid, Benedikt G. Schulze Dieckhoff, Sydney Stewart y Julia Steinhoff-Wagner. "PSII-10 In vitro simulation of biofilm development and detachment in dairy cow troughs within the first 7 days after cleaning". Journal of Animal Science 97, Supplement_3 (diciembre de 2019): 232–33. http://dx.doi.org/10.1093/jas/skz258.473.
Resumen
Abstract Water is one of the most important factors concerning animal health and welfare. Therefore, an impairment of livestock water quality through biofilm development and detachment in dairy cow troughs represents a serious threat. To gain a better understanding of biofilm development and detachment, this study evaluates influencing factors in vitro. Cattle trough materials were inoculated with two naturally occurring bacterial cultures from different dairy farms. In a latin square design, detachment of a biofilm within a recommended cleaning interval of 7 days was investigated via total viable count (TVC) of the surrounding medium, depending on origin of culture, trough material (polyethylene or stainless steel), water temperature (5°C or 25°C) or nutrient availability (10% or 50% of nutrient broth, Merck KGaSA). At day 7, developed biofilm was investigated for TVC, Enterobacteriaceae spp. and with an adenosine triphosphate (ATP)-rapid test. All treatments were replicated at least 3 times. From the 4th day on, TVC in the surrounding medium increased by 1.5 log10 cfu/ml on polyethylene at 5°C, suggesting a maturation and detachment of a grown biofilm. Material and temperature affected biofilm detachment (P < 0.05). In temperature treatments with 25°C, TVC reached maximum within 24h, suggesting that biofilm detached earlier. The composition of the grown biofilm was affected by material, temperature, nutrient level, but not by starting culture. Higher Enterobacteriaceae spp. and TVC were observed on polyethylene than on stainless steel and at higher temperatures compared to lower (P < 0.001, respectively). Nutrient level significantly increased Enterobacteriaceae spp. growth. Rapid ATP-test results showed high Pearson correlations with biofilms TVC (r >0.74; P < 0.001) and might be a practical method to check trough hygiene on farms. Based on our in vitro data, cleaning intervals should be less than 4 days even at low temperatures. Nevertheless, more research is needed to verify data in practice.
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Sitnikova, K. O., U. M. Nemchenko, N. M. Voropaeva, E. V. Grigorova, E. D. Savilov, Yu A. Markova y N. L. Belkova. "The effectiveness of biofilm formation of daily cultures of clinically significant strains of opportunistic bacteria". Acta Biomedica Scientifica 7, n.º 5-1 (8 de diciembre de 2022): 119–28. http://dx.doi.org/10.29413/abs.2022-7.5-1.13.
Resumen
Background. The formation of biofilm structures by microorganisms living in the hospital environment is a serious medical problem. To conduct correct experimental studies, it is necessary to know the speed and efficiency of biofilm formation by clinically significant species of opportunistic bacteria. Aim: to study the kinetics of plankton culture growth and the rate of biofilm formation by clinically significant pathogens of infections associated with medical care to substantiate the methodology of further research. Materials and methods. The strains from the working collection of the Laboratory for Microbiome and Microecology of the Scientific Сentre for Family Health and Human Reproduction Problems were used. Experiments were carried out with conditionally pathogenic microorganisms of the Enterobacteriaceae family and non-fermenting gram-negative bacteria. The optical density was measured, the total microbial number of the cell suspension was determined, and the morphological structure of the biofilm was evaluated using a light microscope on sterile cover glasses for thespecies Pseudomonas aeruginosa, Klebsiella pneumoniae and Serratia marcescens. Results. The duration of the lag phase of the kinetic curve of cell growth varied in isolates of S. marcescens, P. aeruginosa and K. pneumoniae from 1 to 4 and 6 hours of cultivation, respectively. Despite this, the exponential growth phase was the same for all tested isolates and amounted to 4 hours. Thus, isolates of clinically significant species entered the stationary growth phase after 5–10 hours of cultivation and were characterized as fast-growing. On abiotic surfaces, after 8 hours of incubation of the tested cultures, the initial stages of the formation of biofilm structures were observed, after 20 hours the formed multilayer biofilm was visualized, after 24 hours succession occurred, new single cells were attached to the place of the detached structures. Conclusion. The data obtained on the duration of the main stages of growth kinetics compared with the visualization of the formation of biofilm structures on abiotic surfaces should be taken into account when studying the effects of disinfectants, antiseptics and antibacterial drugs on planktonic cells and biofilm associations of clinically significant opportunistic microorganisms.
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Vazquez, Nicolas M., Florencia Mariani, Pablo S. Torres, Silvia Moreno y Estela M. Galván. "Cell death and biomass reduction in biofilms of multidrug resistant extended spectrum β-lactamase-producing uropathogenic Escherichia coli isolates by 1,8-cineole". PLOS ONE 15, n.º 11 (5 de noviembre de 2020): e0241978. http://dx.doi.org/10.1371/journal.pone.0241978.
Resumen
Escherichia coli is the most frequent agent of urinary tract infections in humans. The emergence of uropathogenic multidrug-resistant (MDR) E. coli strains that produce extended spectrum β-lactamases (ESBL) has created additional problems in providing adequate treatment of urinary tract infections. We have previously reported the antimicrobial activity of 1,8-cineole, one of the main components of Rosmarinus officinalis volatile oil, against Gram negative bacteria during planktonic growth. Here, we evaluated the antibiofilm activity of 1,8-cineole against pre-formed mature biofilms of MDR ESBL-producing uropathogenic E. coli clinical strains by carrying out different technical approaches such as counting of viable cells, determination of biofilm biomass by crystal violet staining, and live/dead stain for confocal microscopy and flow cytometric analyses. The plant compound showed a concentration- and time-dependent antibiofilm activity over pre-formed biofilms. After a 1 h treatment with 1% (v/v) 1,8-cineole, a significant decrease in viable biofilm cell numbers (3-log reduction) was observed. Biofilms of antibiotic-sensitive and MDR ESBL-producing E. coli isolates were sensitive to 1,8-cineole exposure. The phytochemical treatment diminished the biofilm biomass by 48–65% for all four E. coli strain tested. Noteworthy, a significant cell death in the remaining biofilm was confirmed by confocal laser scanning microscopy after live/dead staining. In addition, the majority of the biofilm-detached cells after 1,8-cineole treatment were dead, as shown by flow cytometric assessment of live/dead-stained bacteria. Moreover, phytochemical-treated biofilms did not fully recover growth after 24 h in fresh medium. Altogether, our results support the efficacy of 1,8-cineole as a potential antimicrobial agent for the treatment of E. coli biofilm-associated infections.
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Smit, John, Christopher S. Sherwood y Robin FB Turner. "Characterization of high density monolayers of the biofilm bacteriumCaulobacter crescentus: Evaluating prospects for developing immobilized cell bioreactors". Canadian Journal of Microbiology 46, n.º 4 (1 de abril de 2000): 339–49. http://dx.doi.org/10.1139/w99-145.
Resumen
Caulobacters are biofilm-forming members of the natural flora of soil and aquatic environments, which exhibit several characteristics that make them attractive for development of high surface area microbial bioreactors or biosensors. Although caulobacters are well characterized genetically, little is known about their biofilm-forming characteristics as a monoculture, or their tolerance of bioreactor-like conditions. Here we investigated the ability of caulobacters to spontaneously form high-density monolayers on artificial surfaces under a variety of environmental conditions, using phase contrast image analysis to assess biofilm density, and epifluorescence with the vital stain DiBAC(tm) to assess viability. With adequate nutrition, extremely dense monolayers formed within 24-48 h, and maintained near 100% viability in experiments ranging up to 22 days. When areas were abraded to remove cells, repopulation occurred rapidly with characteristics similar to the population of a clean surface. When established monolayers were starved for nutrients, a significant fraction of the cells detached from the surface, and cells remaining on the surface no longer tested as viable. Within 4-6 h of nutrient restoration, however, cells in the monolayer again appeared normal and tested as 100% viable. This is the first demonstration that Caulobacter crescentus is stable and amenable to high density monolayer growth and resists starvation, though some cells may express a programmed response to detach from the surface under severe nutrient limitation.Key words: Caulobacter crescentus, biofilm characterization, image analysis, phase contrast, epifluorescence, vital stains.