Thomas Bartlett

Most of what we know about how bacteria grow and take shape comes from studying rod-shaped model organisms like E. coli and B. subtilis. Yet the pathogens that cause disease display a remarkable diversity of morphologies – spheres, spirals, curves, and more. My lab studies how these unusual shapes are determined, and how they influence infection-relevant traits such as motility, colonization, and antibiotic resistance. Central to these questions is the bacterial cell envelope, a rigid shell that functions like an exoskeleton. It defines shape and dictates how bacteria interact with their environment, much as an animal’s skeleton enables movement and form. The envelope also separates cells from the outside world, is essential for survival, and serves as the primary barrier against antibiotics. This makes it both a fundamental driver of bacterial physiology and one of our best drug targets.  

To uncover how bacteria organize growth into different shapes, we combine approaches that bridge hierarchical scales – from nanometer-scale proteins, to micron-scale cellular organization, to population-level behaviors. We begin with simple morphological questions: How does a pathogen grow into its specific shape? What factors make this possible, and are they potential drug targets? What does this cell shape allow the bacterium to do, and what are the consequences for disease? From there, we use high-throughput genetics and screening to identify factors that pattern  growth, super-resolution microscopy to visualize their effects on morphogenesis, and molecular genetics and biochemistry to define their molecular mechanisms. 

Our group currently focuses on two pathogens. In spheroid Staphylococcus aureus, the leading cause of soft-tissue infections, we study envelope biogenesis and the mechanisms that place division sites in a spheroid cell where elongation cues are absent. In Vibrio cholerae, which causes the epidemic diarrheal disease cholera, we study how curvature factors bend the bacterium into a curved rod and allow it to corkscrew into gels to colonize the gut. Together, these projects reveal new principles of bacterial growth and shape while pointing to strategies for combating infectious disease. 

Please see our Wadsworth lab website for more information on our ongoing research projects.
 

Current major activities

• Identifying factors underlying envelope assembly in Staphylococcus aureus
• Understanding the geometric cues governing cell division in coccoid bacteria
• Investigating mechanisms of cell curvature in Vibrio cholerae
• Exploring links between morphology and infection in coccoid Staph and curved-rod Vibrio