Rolling

Staphylococcus aureus Biofilm Rolling Along the Lumen of a Glass Tube

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 11-hour time-lapse video sequence shows a side view of a S. aureus biofilm microcolony rolling along the side wall of a square glass tube. Water containing brain-heart infusion nutrients flows through the tube at a flow rate of 1 ml/min, giving an average flow velocity of 2.1 cm/s. The biofilm microcolony appears to be attached to the glass by sticky appendages. The rolling motion appears 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. It then rolls slightly and reattaches 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.

Microscopy: bright field using an Olympus BH2 microscope. Time-lapse images were captured on a Scion VG-5 PCI framestore board using Scion Image software (www.scioncorp.com).

Movie Authors: Cory Rupp, Suzanne Wilson, Paul Stoodley

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.

Acknowledgments
This work was supported by the National Institutes of Health grant RO1 GM60052 and the W. M. Keck Foundation. Thanks to Suzanne Wilson for growing the biofilm.

Visual Resources
"Staphylococcus aureus Biofilm Rolling Along the Lumen of a Glass Tube. © Cory Rupp, Suzanne Wilson and Paul Stoodley, authors. Licensed for use, ASM MicrobeLibrary."