Cammie Lesser MD, PhD, is a Research Scholar and Attending Physician at Massachusetts General Hospital and an Associate Professor of Medicine (Microbiology) at Harvard Medical School. She is a graduate of the University of California, San Francisco MD-PhD program, where she conducted her graduate students on mRNA processes in the laboratory of Dr. Christine Guthrie. She then completed her training in internal medicine and infectious disease, where she began her research on bacterial pathogens in the laboratory of Dr. Sam Miller. The Lesser Lab studies aspects related to type III secretion systems, complex nanomachines used by many pathogenic bacteria to directly inject tens of proteins into host cells. Efforts focus on studying how secreted proteins are defined within bacteria and their roles in promoting bacterial spread and survival once injected inside host cells. In addition, the lab is working to translate these studies towards the development of designer probiotics that encode modified type III secretion systems that enable them to deliver therapeutic payloads, rather than virulence proteins, directly into the gut lumen. It is their hope that these bacteria will lead to a new paradigm that increases therapeutic efficacy while decreasing off-target side effects.