A statistical analysis of the effect of substrate utilization and shear stress on the kinetics of biofilm detachment

Peyton, Brent M.; Characklis, William G.

doi:10.1002/bit.260410707

Cited by 159 publications

(91 citation statements)

References 16 publications

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“…In most fixed biomass systems, stable and higher flow rates have the advantage of limiting biofilm growth (Peyton and Characklis, 1993;Melo and Vieira, 1999;Cloete et al, 2003), since they produce thinner and more cohesive layers less prone to release bacteria into the bulk water. However, these conditions are not always feasible to maintain in drinking water networks.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of drinking water biofilm in flow/non-flow conditions

2007

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A B S T R A C TDrinking water biofilm formation on polyvinyl chloride (PVC), cross-linked polyethylene (PEX), high density polyethylene (HDPE) and polypropylene (PP) was followed in three different reactors operating under stagnant or continuous flow regimes. After one week, a quasi-steady state was achieved where biofilm total cell numbers per unit surface area were not affected by fluctuations in the concentration of suspended cells. Metabolically active cells in biofilms were around 17-35% of the total cells and 6-18% were able to form colony units in R 2 A medium. Microbiological analysis showed that the adhesion material and reactor design did not affect significantly the biofilm growth. However, operating under continuous flow (0.8-1.9 Pa) or stagnant water had a significant effect on biofilm formation: in stagnant waters, biofilm grew to a less extent. By applying mass balances and an asymptotic biofilm formation model to data from biofilms grown on PVC and HDPE surfaces under turbulent flow, specific growth rates of bacteria in the biofilm were found to be similar for both materials (around 0.15 day À1) and much lower than the specific growth rates of suspended bacteria (around 1.8 day À1 ).

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Section: Introductionmentioning

confidence: 99%

Dynamics of drinking water biofilm in flow/non-flow conditions

2007

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“…Detachment refers to the release of microbial cells and their associated matrix polymers from the biofilm to the bulk fluid bathing the film. Some of the factors that have been suggested to be important in biofilm detachment include matrix-degrading enzymes (1,3,14,30), microbially generated gas bubbles (16), nutrient levels and microbial growth status (2,12,18,22,23,25), availability of multivalent cross-linking cations (2,4,29), fluid shear stress (18)(19)(20)27), contact attrition (5), quorum-sensing signals (1,9), and the activation of a lytic bacteriophage (32).…”

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confidence: 99%

Hypothesis for the Role of Nutrient Starvation in Biofilm Detachment

Hunt

Werner

Huang

et al. 2004

Appl Environ Microbiol

248

180

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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.

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“…Most studies of detachment of microbial cells use biofilms formed under dynamic conditions in which detachment is induced by liquid flow. These studies have shown the influence of numerous factors on the detachment of bacterial cells, such as nutrient limitation (21,38,45), growth phase (38), growth rate (40, 41), shape of the microbial cells (20), and nature of the substrate material (20,40,46). Other authors have studied the transfer of bacterial cells simply deposited on a surface (36, 37).…”

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confidence: 99%

Construction and Analysis of Fractional Multifactorial Designs To Study Attachment Strength and Transfer of Listeria monocytogenes from Pure or Mixed Biofilms after Contact with a Solid Model Food

Midelet

Kobilinsky

Carpentier

2006

Appl Environ Microbiol

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The aim of this study was to establish which of seven factors influence the adhesion strength and hence bacterial transfer between biofilms containing Listeria monocytogenes (pure and two-species biofilms) and tryptone soya agar (TSA) as a solid organic surface. The two-species biofilms were made of L. monocytogenes and one of the following species of bacteria: the nonpathogenic organisms Kocuria varians, Pseudomonas fluorescens, and Staphylococcus sciuri and CCL 63, an unidentified gram-negative bacterium isolated from the processing plant environment. We used biofilms prepared under conditions simulating open surfaces in meat-processing sites. The biofilm's adhesion strength and population were evaluated by making 12 contacts on a given whole biofilm (4.5 cm 2 ), using a new slice of a sterilized TSA cylinder for each contact, and plotting the logarithm CFU · cm ؊2 detached by each contact against the contact number. Three types of detachment kinetics were observed: biphasic kinetics, where the first slope may be either positive or negative, and monophasic kinetics. The bacteria that resisted a chlorinated alkaline product and a glutaraldehyde-and quaternary ammonium-based disinfectant had greater adhesion strengths than those determined for untreated biofilms. One of the four non-Listeria strains studied, Kocuria varians CCL 56, favored both the attachment and detachment of L. monocytogenes. The stainless steel had smaller bacterial populations than polymer materials, and non-Listeria bacteria adhered to it less strongly. Our results helped to evaluate measures aimed at controlling the immediate risk, linked to the presence of a large number of CFU in a foodstuff, and the delayed risk, linked to the persistence of L. monocytogenes and the occurrence of slightly contaminated foods that may become dangerous if L. monocytogenes multiplies during storage. Cleaning and disinfection reduce the immediate risk, while reducing the delayed risk should be achieved by lowering the adhesion strength, which the sanitizers used here cannot do at low concentrations.Microorganisms in foods may be derived from the raw materials, ingredients, personnel, or the work environment. Epidemics of listeriosis, which is rare but serious when it affects the so-called at-risk population (43), have been traced back to environmental contamination of food processing areas (48). Listeria monocytogenes genotypes, absent from the raw materials, may be repeatedly found in the finished products and on work surfaces (3). It is therefore interesting to identify the factors that affect adhesion strength and hence transfer of L. monocytogenes from an inert surface to a food following contact. Such data can be useful for quantitative analysis of the risks associated with ready-to-eat foods that may be contaminated during manufacture (11,18). Most studies of detachment of microbial cells use biofilms formed under dynamic conditions in which detachment is induced by liquid flow. These studies have shown the influence of numerous factors on the detachme...

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A statistical analysis of the effect of substrate utilization and shear stress on the kinetics of biofilm detachment

Cited by 159 publications

References 16 publications

Dynamics of drinking water biofilm in flow/non-flow conditions

Dynamics of drinking water biofilm in flow/non-flow conditions

Hypothesis for the Role of Nutrient Starvation in Biofilm Detachment

Construction and Analysis of Fractional Multifactorial Designs To Study Attachment Strength and Transfer of Listeria monocytogenes from Pure or Mixed Biofilms after Contact with a Solid Model Food

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