COL Ressner completed her fellowship in Infectious Diseases (ID) at Brooke Army Medical Center in 2008. She is a Professor of Medicine at the Uniformed Services University of the Health Sciences (USUHS). In 2022, she assumed the role of Senior Medical Advisor at the Walter Reed Army Institute of Research. COL Ressner previously served as the Walter Reed National Military Medical Center (WRNMMC) Chair of Infection Control and Prevention and as the Antimicrobial Stewardship Program (ASP) Director. Other leadership roles include Interim and Assistant Chief for the WRNMMC Department of Medicine (DOM), Interim and Assistant Chief for the WRNMMC ID Service, and four years as the Program Director for the combined Army and Navy National Capital Consortium ID Fellowship program.  Research and clinical interests include multi-drug resistant organisms, tropical medicine, infection control and prevention and antimicrobial stewardship.