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Center for Biofilm Engineering
Movie Description:
Staphylococcus aureus biofilm rolling along the lumen of a glass
tube
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Staphylococcus aureus, an opportunistic human pathogen, is
commonly associated with nosocomial infections and often colonizes
medical devices such as catheters. Using glass flow cells, biofilms
can be monitored in situ microscopically.
This is a 11.5 hour time-lapse video sequence showing a side view of a
S. aureus biofilm microcolony rolling along the side wall of a
square glass tube. Water containing brain-heart infusion broth was
flowing through the tube at a flow rate of 1 ml/min, giving an average
flow velocity of 1.7 cm/s. The biofilm microcolony appeared to be
attached to the glass by sticky appendages or "tethers". The rolling
motion appeared to be caused by the continual attachment and
detachment of the biofilm from the glass surface. First the
microcolony detaches from the upstream side, where presumably the
shear force overcomes the attachment force of the tether. It then
jerks forward in a rolling motion and tethers reattach at the
downstream side.
The migration of bacterial microcolonies along the lumen of catheters
(tubes used to deliver fluids into the body or drain fluids from the
body), endotracheal tubes (tubes used to maintain an airway), or
dental unit water lines may be an important consideration in the
dissemination of pathogens such as S. aureus into patients. In
industrial systems, the movement of biofilms along the walls of
process pipes may result in the spread of contamination to other parts
of the system. By moving along the pipe wall, the biofilm can spread
without detaching and entering a planktonic (free swimming or
floating) phase in which the bacteria are often more susceptible to
antimicrobial agents such as antibiotics or biocides.
Acknowledgments: This work was supported by the National Institutes of
Health grant RO1 GM60052 and the W. M. Keck Foundation. The movie
sequence is also available at the ASM MicrobeLibrary (www.microbelibrary.org).
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| Movie Author: Rupp, C.J., Wilson, S, and
Stoodley, P. |
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| Reference:
Rupp, C.J., C. Fux, and P. Stoodley. 2005. Viscoelasticity of
Staphylococcus aureus biofilms in response to fluid shear resists
detachment and facilitates rolling migration. Appl. Envron.
Microbiol. 71(4): 2175-2178.
Further Reading:
Klapper, I., C. J. Rupp, R. Cargo, B. Purevdorj, and P. Stoodley.
2002. A viscoelastic fluid description of bacterial biofilm material
properties. Biotechnol. Bioeng. 80: 289-96.
Stoodley, P., Z. Lewandowski, J. D. Boyle, and H. M. Lappin-Scott.
1999.
Structural deformation of bacterial biofilms caused by short term
fluctuations in flow velocity: an in situ demonstration of biofilm
viscoelasticity. Biotechnol. Bioeng. 65:83-92.
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Viscoelasticity of Staphylococcus aureus biofilm
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This time-lapse video sequence shows Staphylococcus aureus
biofilm cell clusters in a glass flow cell stretching and contracting
as the flow rate of the nutrient feed is turned up and down between 0
and 9 ml/min. The amount of stretching (strain) can be related to the
shear stress caused by the fluid flowing in the flow cell. The strain
is then used to investigate the material properties of the attached
biofilm. This data demonstrates that the S. aureus biofilm is a
viscoelastic material. S. aureus is commonly found on the skin
and as part of the naturally occurring oral, nasal, and vaginal
microbial flora, where in most people it lives harmlessly. However,
S. aureus is also an opportunistic human pathogen and is commonly
associated with nosocomial infections. S. aureus often
colonizes on medical devices such as venous and renal catheters and is
associated with infections such as osteomyelitis (infection of the
bone), endocarditis (infection of the heart valves), and bacteremia
(infection of the blood). An understanding of the material properties
of biofilms is important in predicting how biofilms may respond when
exposed to fluid shear forces. Detachment of clumps of pathogenic
bacteria from biofilms, or the flow of biofilms across surfaces, may
be an important consideration in the dissemination of the infection in
the host or from catheters and other medical delivery systems.
Additionally, this information may be useful in designing novel
strategies for biofilm removal or stabilization.
Acknowledgments: This work was supported by the National Institutes of
Health grant RO1 GM60052 and the W. M. Keck Foundation. The movie
sequence is also available at the ASM MicrobeLibrary (www.microbelibrary.org). |
| Movie Authors: Rupp, C.J.,
Wilson, S, and Stoodley, P. |
| Reference:
Rupp, C.J., C. Fux, and P. Stoodley. 2005. Viscoelasticity of
Staphylococcus aureus biofilms in response to fluid shear resists
detachment and facilitates rolling migration. Appl. Envron.
Microbiol. 71(4): 2175-2178.
Further Reading:
Klapper, I., C. J. Rupp, R. Cargo, B. Purevdorj, and P. Stoodley.
2002. A viscoelastic fluid description of bacterial biofilm material
properties. Biotechnol. Bioeng. 80: 289-296.
Stoodley, P., Z. Lewandowski, J. D. Boyle, and H. M. Lappin-Scott.
1999.
Structural deformation of bacterial biofilms caused by short term
fluctuations in flow velocity: an in situ demonstration of biofilm
viscoelasticity. Biotechnol. Bioeng. 65:83-92. |
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