Bridges Lab Looks to Unlock Secrets of Bacteria Communication

Disease-causing germs and waterborne microbes bunched together in communities known as biofilms can be harmful in pipes. As solo swimmers, those same bacteria can be innocuous.

Drew Bridges, assistant professor of biological sciences, investigates how bacteria respond to extracellular sensory information to make developmental decisions.

Bacteria can distinguish "self" from "non-self" when deciding whether to form biofilms, Bridges said. For example, when signaling molecules produced by closely related species are detected, bacteria commit to forming biofilms. But when signals from competing bacteria are detected, these same bacteria exit biofilms.

Understanding how and why bacteria respond to certain stimuli could have applications in the treatment of disease, food production, water purification or other industrial settings.

"Right now, the antibiotics we use just kill bacteria, but bacteria evolve in ways that allow for resistance," said Bridges, who joined Carnegie Mellon in 2022. "A strategy to change their behaviors rather than just kill them could have many implications."

Bridges studied cell biology as a doctoral student at Dartmouth. Afterwards, he pivoted to microbiology.

"It's an amazing time to be a biologist or a person in biomedicine because of the ability to sequence genomes and the pace that we can do research," Bridges said.

He joined the Center for the Physics of Biological Function at Princeton University as the Howard Hughes Medical Institute Fellow of the Damon Runyan Cancer Research Foundation in 2017.

At Princeton he studied cell-to-cell communication in the bacteria that causes cholera, Vibrio cholerae, and how that communication affects whether the bacteria grow into a biofilm or stay as single-celled organisms. Bridges pioneered new imaging approaches combined with techniques from genetics, biochemistry and biophysics theory to visualize, in real-time, the biofilm life cycle of V. cholerae and identify important steps for how V. cholerae biofilms disperse.

For his efforts, he was named a finalist for the 2022 Blavatnik Regional Awards for Young Scientists.

"Postdoctoral periods are really a sort of a transformative time in one's career where you have total independence, and you use what you learn to set up the rest of your career" he said. "It's a unique point where you're fully trained and in a lab within the scope of what you want to do and where you can also be creative. You don't have many responsibilities other than developing a research program."

At Carnegie Mellon, Bridges has two senior scientists and a postbaccalaureate researcher working with him. Graduate students in the Mellon College of Science are rotating through his lab as well. His goal is to have a diversity of fields represented in the group.

"I hope to have a multidisciplinary lab with folks who have backgrounds in biology, chemistry, physics. It's great regardless of what field they come from if they have a quantitative background," he said. "I'm particularly excited to have undergraduates start to work on projects."

In the long term, Bridges aims to expand his research to examine other microorganisms and their unique lifestyles to learn what principles are general and which are species-specific. The discoveries will be relevant to infection and could inform the development of approaches to manipulate bacterial behavior, potentially leading to new strategies for controlling disease.