Fig. 5: Type IV Pili-Induced Dragging of a Bacterium

Some bacteria use type IV pili to move along surfaces within a biofilm. (Biofilms are to viscous for bacteria to swim through with flagella.) The bacterium extends and anchors its pili. As the pili retract the bacterium is pulled forward. This enables the bacterium to drag themselves through biofilms on environmental surfaces and alternates with a type-IV pili-induced slingshotting motion (see Fig. 6). The top illustration shows a bacterium dragging itself or "crawling" along a surface. Bacteria with polar pili are also able to pull themselves upright and "walk" along the surface as shown in the bottom illustration.

Illustration of Type IV Pili-Induced Dragging of a Bacterium.jpg by Gary E. Kaiser, Ph.D.
Professor of Microbiology, The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at

Creative Commons License

Last updated: August, 2018
Please send comments and inquiries to Dr. Gary Kaiser