Swarming behaviors are widespread in nature seen in synchronously darting fish schools and locusts sweeping across landscapes in coordinated waves. On winter evenings before dusk hundreds of thousands of starlings create mesmerizing pulsing patterns in the sky known as murmuration moving as one to evade predators and communicate.  

But swarming isn’t exclusive to birds insects or fish bacteria also exhibit collective movement on a microscopic scale. Some microbes rely on swarming to spread across surfaces colonize new environments and outcompete rivals.

A new study by researchers at the Biodesign Center for Fundamental and Applied Microbiomics at Arizona State University reveals that certain bacteria move in synchronized waves and bursts forming scattered microcolonies. This coordinated movement mirrors strategies seen in nature such as plants dispersing seeds or fungi releasing spores. 

Bacteria from the genus Capnocytophaga spread in intricate organized patterns allowing them to adapt to changing environments. Commonly found in the human mouth these bacteria are linked to gingivitis and periodontal diseases. They can also form biofilms and in some cases cause fatal septic infections following canine bites.

This research offers new insights into microbial ecosystems potentially leading to advancements in oral and gut health treatments.  

The human microbiome hosts many understudied microbes. For example the genus Capnocytophaga found in nearly every human mouth remains largely unexplored says Abhishek Shrivastava corresponding author and assistant professor at ASU’s School of Life Sciences. Our study sheds light on the developmental processes of these microbes providing a deeper understanding of their role in health.

The study is published in the latest issue of the Multidisciplinary Journal of Microbial Ecology and includes contributions from ASU researchers and colleagues from the Max Planck Society in Germany.

Bacterial Close-Up

Bacteria of the Capnocytophaga genus are a natural part of the healthy human oral microbiome a diverse community of bacteria and microorganisms residing in the mouth. However imbalances in this ecosystem can contribute to gum disease or infections particularly in individuals with weakened immune systems. Additionally the transfer of pathogenic Capnocytophaga from canine saliva to humans can lead to severe sepsis and in some cases death. Understanding how Capnocytophaga move and spread may offer valuable insights into bacterial colonization in the mouth and the formation of biofilms complex bacterial communities on teeth and gums that contribute to disease.  

To study bacterial swarming researchers employed high-resolution time-lapse microscopy to track movement patterns over time. By growing the bacteria on soft agar plates under oxygen-free conditions mimicking the deep layers of the human mouth they observed and recorded bacterial movements over several days.Researchers used computer models to simulate C. ochracea movement revealing predictable swarm patterns. Unlike traditional bacteria these microbes expand in bursts shift to wave-like motion and scatter into microcolonies resembling seed dispersal. They also transport non-motile bacteria and viruses influencing microbial interactions. Understanding these behaviors could lead to new strategies for infection control and microbiome-based therapies.

Source: https://news.asu.edu/20250324-science-and-technology-swarm-science-oral-bacteria-move-waves-spread-and-survive