Bacteria Spread in Surprising New Ways Without Propellers

Studies reveal bacteria can migrate across surfaces through fluid currents and molecular gear systems, even when their usual flagella are disabled.

Mar. 13, 2026 at 5:22am

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New research from Arizona State University shows that bacteria can travel in unexpected ways even when their usual propulsion system fails. Normally, bacteria move using flagella, slender, whip-like structures that spin to push the cells forward. The new studies reveal that microbes can still spread across surfaces without these structures, either by generating fluid currents through fermentation or using a specialized molecular 'gearbox' system.

Why it matters

Learning how bacteria move, even without their typical flagella, is critical for developing better strategies to prevent infections. The findings suggest that simply blocking flagella may not be enough to stop bacterial spread, as microbes can use alternative movement mechanisms to colonize medical devices, wounds, and food processing equipment.

The details

In one study, researchers found that E. coli and salmonella can migrate across moist surfaces by fermenting sugars and creating tiny fluid currents that carry them forward - a newly identified behavior called 'swashing'. In another study, a different group of bacteria called flavobacteria was shown to control its movement using a microscopic molecular 'gearbox' that can reverse direction like a biological snowmobile. These unexpected movement strategies highlight the diverse ways bacteria can spread, even when their usual propulsion systems fail.

  • The swashing study was published in the Journal of Bacteriology in 2026.
  • The molecular gearbox study was published in the journal mBio in 2026.

The players

Navish Wadhwa

Researcher at the Biodesign Center for Mechanisms of Evolution and assistant professor in the Department of Physics at Arizona State University.

Shrivastava

Researcher at the Biodesign Center for Fundamental and Applied Microbiomics, the Biodesign Center for Mechanisms of Evolution, and assistant professor in the School of Life Sciences at Arizona State University.

Arizona State University

The university where the research on bacterial movement was conducted.

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What they’re saying

“We were amazed by the ability of these bacteria to migrate across surfaces without functional flagella. In fact, our collaborators originally designed this experiment as a 'negative control,' meaning that we expected (once rendered) flagella-less, the cells to not move. But the bacteria migrated with abandon, as if nothing were amiss, setting us off on a multiyear quest to understand how they were doing it.”

— Navish Wadhwa, Researcher

“We are very excited to have discovered an extraordinary dual-role nanogear system that integrates a feedback mechanism, revealing a controllable biological snowmobile and showing how bacteria precisely tune motility and secretion in dynamic environments. Building on this breakthrough, we now aim to determine high-resolution structures of this remarkable molecular conveyor to visualize, at atomic precision, how its moving parts interlock, transmit force and respond to mechanical feedback. Unraveling this intricate design will not only deepen our understanding of microbial evolution but also inspire the development of next-generation bioengineered nanomachines and therapeutic technologies.”

— Shrivastava, Researcher

What’s next

Researchers plan to further study the molecular structures and mechanisms behind the bacterial 'gearbox' system to better understand how it allows microbes to precisely control their movement and secretion of proteins in dynamic environments.

The takeaway

These findings highlight the surprising diversity of strategies bacteria have evolved to spread and colonize new environments, even when their typical propulsion systems are disabled. This underscores the need for new approaches to combat bacterial infections that go beyond simply targeting flagella, and instead focus on controlling the environmental factors and molecular mechanisms that enable bacterial movement and spread.