An in vitro urinary tract catheter system to investigate biofilm development in catheter-associated urinary tract infections

Dohnt, Katrin; Sauer, Marie; Müller, Maren; Atallah, Karin; Weidemann, Marina; Gronemeyer, Petra; Rasch, Detlev; Tielen, Petra; Krull, Rainer

doi:10.1016/j.mimet.2011.09.002

Cited by 33 publications

(24 citation statements)

References 37 publications

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“…For the second and main cultures, a minimal medium developed during the study ensured balanced growth of all strains, an important prerequisite for the 13 C-flux approach [15]. The osmolality of this medium was 500 mosmol·kg −1 , which reflects that of human urine [18]. The medium contained the following (per liter): 2.5 g glucose, 13.0 g KH 2 PO 4 ×2 H 2 O, 20.6 g K 2 HPO 4 , 0.49 g MgSO 4 ×7 H 2 O, 2.5 g NH 4 Cl, 1.41 g Na 2 SO 4 , 0.085 g CaCl 2 ×2 H 2 O, 1.2 mg FeSO 4 ×7 H 2 O, and 25 mg 3,4-dihydroxybenzoate.…”

Section: Methodsmentioning

confidence: 99%

Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa

et al. 2014

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Pseudomonas aeruginosa is a human pathogen that frequently causes urinary tract and catheter-associated urinary tract infections. Here, using 13C-metabolic flux analysis, we conducted quantitative analysis of metabolic fluxes in the model strain P. aeruginosa PAO1 and 17 clinical isolates. All P. aeruginosa strains catabolized glucose through the Entner-Doudoroff pathway with fully respiratory metabolism and no overflow. Together with other NADPH supplying reactions, this high-flux pathway provided by far more NADPH than needed for anabolism: a benefit for the pathogen to counteract oxidative stress imposed by the host. P. aeruginosa recruited the pentose phosphate pathway exclusively for biosynthesis. In contrast to glycolytic metabolism, which was conserved among all isolates, the flux through pyruvate metabolism, the tricarboxylic acid cycle, and the glyoxylate shunt was highly variable, likely caused by adaptive processes in individual strains during infection. This aspect of metabolism was niche-specific with respect to the corresponding flux because strains isolated from the urinary tract clustered separately from those originating from catheter-associated infections. Interestingly, most glucose-grown strains exhibited significant flux through the glyoxylate shunt. Projection into the theoretical flux space, which was computed using elementary flux-mode analysis, indicated that P. aeruginosa metabolism is optimized for efficient growth and exhibits significant potential for increasing NADPH supply to drive oxidative stress response.

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Section: Methodsmentioning

confidence: 99%

Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa

et al. 2014

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“…The frequently used artificial urine formulation [9], however, contains substantial amounts of yeast extract, leading to an unrealistically high nutrient supply. Further improvements included replacement of yeast extract by a trace element solution [10]. However, the central role of iron limitation in the urinary tract, part of the endogenous antibacterial defense, has mostly been neglected.…”

Section: How Close To Reality Can a Biofilm Model Be?mentioning

confidence: 99%

In Vitro Biofilm Models for Device-Related Infections

Buhmann

Stiefel

Maniura‐Weber

et al. 2016

Trends in Biotechnology

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“…22) and post-attachment dynamics including surface residence time 23 and catch-bond adhesion strength 24 , our results demonstrate that attachment can be enhanced by lower, commonly occurring shear rates with a mechanism virtually independent from specific adhesion properties. For example, P. aeruginosa biofilms are a frequent cause of infection in catheters 3 , where typical shear rates are of the order of 15 s −1 (ref. 12), indicating that flow effects must be carefully considered in the design of these and other biomedical devices.…”

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Bacterial transport suppressed by fluid shear

2014

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Bacteria often live in dynamic fluid environments 1-3 and flow can a ect fundamental microbial processes such as nutrient uptake 1,4 and infection 5 . However, little is known about the consequences of the forces and torques associated with fluid flow on bacteria. Through microfluidic experiments, we show that fluid shear produces strong spatial heterogeneity in suspensions of motile bacteria, characterized by up to 70% cell depletion from low-shear regions due to 'trapping' in high-shear regions. Two mathematical models and a scaling analysis accurately capture these observations, including the maximal depletion at mean shear rates of 2.5-10 s −1 , and reveal that trapping by shear originates from the competition between the cell alignment with the flow and the stochasticity in the swimming orientation. We show that this shear-induced trapping directly impacts widespread bacterial behaviours, by hampering chemotaxis and promoting surface attachment. These results suggest that the hydrodynamic environment may directly a ect bacterial fitness and should be carefully considered in the study of microbial processes.We investigated the effect of flow on motile bacteria by tracking them in precisely controlled laminar flows generated in a microfluidic channel (Fig. 1a). To ensure that the dominant velocity gradients occurred in the horizontal observation plane, at the channel mid-depth, we used a microchannel with aspect ratio H /W > 1 (height H = 750 µm; width W = 425 µm). In that plane, the velocity profile, u(y) = U [1 − 4(y/W ) 2 ], where U is the flow velocity at the channel centreline, is parabolic, and, thus, the shear rate S(y) = du/dy = −8yU /W 2 varies linearly with distance y across the channel and is zero at the centreline (Fig. 1b). In this flow, smooth-swimming Bacillus subtilis bacteria swam unperturbed in straight paths (Fig. 1c) when near the centre of the channel, where the local shear rate was small. Conversely, in high-shear-rate regions, trajectories exhibited frequent loops resulting from rotation of the swimming bacteria by the hydrodynamic torque imparted by the local shear (Fig. 1d). The opposite handedness of the loops on either side of the channel centreline reflects the opposite sign of the shear rate (Fig. 1c,d and Supplementary Movie 1). As shown below, these looping trajectories resulted in bacteria becoming trapped in the high-shear region of the channel.At the population scale, this trapping effect resulted in a marked depletion of cells from the central, low-shear region of the flow, and consequently, in an accumulation in the flanking regions of higher shear. When the flow was impulsively started from rest, the initially uniform distribution of cells over the imaging region across the channel width (Fig. 1e) rapidly (5-10 s) evolved into a distribution characterized by considerably fewer cells in the central part of the channel (Fig. 1f-h). The magnitude of the depletion was severe, with local cell concentrations dropping by 70% (Fig. 1h). The absence of depletion in control experime...

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An in vitro urinary tract catheter system to investigate biofilm development in catheter-associated urinary tract infections

Cited by 33 publications

References 37 publications

Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa

Robustness and Plasticity of Metabolic Pathway Flux among Uropathogenic Isolates of Pseudomonas aeruginosa

In Vitro Biofilm Models for Device-Related Infections

Bacterial transport suppressed by fluid shear

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