Bacteria's Ability to Sense Chemical Changes Across Their Cell Bodies Uncovered

Scientists at the University of Sheffield have discovered a new sensory capability in bacteria that could transform treatments for bacterial infections.

It was previously believed that bacteria could not directly detect changes in chemical concentrations due to their small size. A recent study, however, has disproved decades of accepted scientific theory and demonstrated that bacteria can, in fact, directly and extremely precisely sense their chemical environment along the length of their cell bodies.

The study published today in Nature Microbiology represents a significant advancement in the creation of novel therapies that alter bacterial motility to increase the effectiveness of antibiotics.

In principle, cells can figure out whether they are moving towards or away from a nutrient source in two different ways. First, they can wander randomly and measure if the concentration increases or decreases over time. Alternatively, cells can measure changes in concentration over the length of their bodies, allowing them to directly move towards the source. Our research demonstrates that bacteria can do the latter, which was previously thought beyond their capabilities due to their tiny size.”

Dr. William Durham, Senior Lecturer and Study Senior Author, Biological Physics, Department of Physics and Astronomy, University of Sheffield

Durham continued, “Bacteria then use this information to navigate across surfaces toward chemical sources using tiny grappling hooks called pili.”

The researchers mapped out how individual cells responded to precise changes in nutrient concentrations using a combination of cutting-edge microfluidic experiments and novel P. aeruginosa strains whose motility systems were engineered so they could be directly visualized using powerful microscopes. They discovered that these cells are capable of “spatial sensing,” which is the ability to compare nutrient concentrations along the length of their cell bodies.

This work overturns our understanding of how bacteria navigate and sense their environment. As such, it sheds new light on how bacteria could direct their motility during human infection and potentially how it could be manipulated by different clinical treatments.”

Dr. Jamie Wheeler, Postdoctoral Researcher and Study Lead Author, Department of Physics and Astronomy, University of Sheffield

The finding implies that bacteria may sense changes in their chemical environment without necessarily moving and that the closely spaced bacteria within localized infections may be able to use this information to direct their behavior. This capability begs new questions regarding the processes by which bacteria carry out these microscopic measurements and how antimicrobial treatments might affect them.

Dr. Wheeler added, “As is often the case, answering one question has raised a whole new set of unknowns. Exciting new experiments are already planned to continue writing this new chapter in our understanding of how bacteria navigate through their environment.”