
Mark V. Williams, MD, FACP, MHM
Division Chief, Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Mark V. Williams, MD, FACP, MHM began his collaboration with the Division’s experienced leadership team in October 2021 to build one of the premier academic divisions in the nation. A Past-President of the Society of Hospital Medicine, Founding Editor of the Journal of Hospital Medicine and one of the first 10 Masters in Hospital Medicine, Mark brings his expertise in quality improvement, teamwork, and care transitions to this prestigious institution and talented group.

Carol Faulk, MD
Assistant Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Carol Faulk, MD, is an Assistant Professor of Medicine with interests in resident well-being and medical education. She is core faculty and Director of Well-being for the Internal Medicine residency program. She is also co-director of the Internal Medicine-Advanced Clinical Rotation, which is a rotation similar to a traditional medicine sub-internship for the phase III medical students. She attends on a mix of the General Medicine Inpatient teaching service (FIRM medicine), Procedure team, and Hospitalist Direct Care.

Jennifer Feldmann, MSN, ACNP-BC
Nurse Practitioner
- Phone: 314-362-1700
- Fax: 314-362-9878
Jennifer Feldmann MSN, ACNP-BC is an acute care nurse practitioner within the Division of Hospital Medicine at WashU School of Medicine. She joined the Division of Hospital Medicine initially in 2010 and brings 28 years of critical care nursing and advanced practice experience. Other experience includes Medical Director of Advanced Practice with BJCMG and lead Advanced Practice Provider on the Hospital Medicine service line council. Jennifer’s interests outside clinical practice are Advanced Practice leadership and Advanced Practice Fellowships to assist in successful transition from novice to experienced Advance Practice Provider.

Kathryn Filson, MD
Assistant Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Kathryn Filson, MD, is an Assistant Professor of Medicine and Co-Director of Patient Care Operations within the Division of Hospital Medicine. She has an interest in clinical patient care, system wide operations, medical education and financial structures. She is the Chair of the Compensation Committee within the Division of Hospital Medicine and helped develop the current bonus incentive structure. Dr. Filson has been with the Department of Medicine since 2018 and spends her clinical time attending on direct patient care services & supervising residents on the inpatient Firm Medicine teams.

Jaime Flores-Ruiz, MD
Instructor in Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Dr. Jaime Flores-Ruiz, MD, holds the position of Instructor in Medicine in the Division of Hospital Medicine. In this role, he serves as the primary physician for medicine inpatients at Barnes-Jewish Hospital. Additionally, he is responsible for supervising interns and residents who are rotating on the Hospital Medicine service. Dr. Flores-Ruiz also works as an Internal Medicine consultant at the Psychiatric Care at Delmar Center. He is a member of the IDEAS committee, which focuses on improving health quality. As part of this committee, he contributes to initiatives aimed at enhancing healthcare practices and outcomes. Dr. Flores-Ruiz volunteers at Affinia Healthcare Clinic providing post-hospital care to patients who face socio-economic barriers and have limited access to healthcare services.

Jerry Fong, MD
Instructor in Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Dr. Jerry Fong joined the Division of Hospital Medicine as an Instructor in Medicine in July 2024. He graduated magna cum laude from Washington University in St. Louis in 2013, majoring in biomedical engineering with a minor in computer science. His research focused on targeted drug delivery to tumors. He completed his Medical Scientist Training Program at Washington University, where he developed an algorithm to identify leukemia and lymphoma subclones from sequencing data. He received the Ruth L. Kirschstein National Research Service Award for his work. In 2021, he earned his combined doctorate of medicine and doctorate of philosophy in computational and systems biology. He completed his internal medicine internship and residency at Barnes-Jewish Hospital/Washington University School of Medicine.

J. Matt Freer, MD
Associate Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
James Matthew Freer, MD, is an Associate Professor of Medicine and member of the Society of Hospital Medicine. He works on the hospitalist service at both BJH and BJWC and attends on the inpatient medicine teaching service and the bedside procedure service. His interests include teaching of medical students and residents and supervising residents performing bedside procedures. Since 2007, Dr. Freer has served as the Director of the Procedure Service. He served as the editor and authored much of the Washington Manual of Bedside Procedures. Dr. Freer has also authored numerous book chapters and two papers on a variety of topics. Dr. Freer has been the invited discussant at the Clinicopathologic Conference (CPC) seven times. His other areas of interest include procedural simulation training, Point of Care Ultrasound (POCUS), and clinical operations at BJWC hospital.

Michelle Freilich, MD
Instructor in Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Michelle Freilich, MD, is an Instructor in Medicine in the Division of Hospital Medicine. She joined the division in June 2023 after completing her internal medicine residency at Washington University in St. Louis/Barnes-Jewish Hospital. Her primary role is direct patient care of hospitalized patients. She has a particular interest in nocturnist medicine and resident education. She is also interested in clinical operations and serves on the patient care operations committee.

Hannah Gill, PA-C, MMS
Physician Assistant
- Phone: 314-362-1700
- Fax: 314-362-9878
Hannah Gill, PA-C, MMS is a Physician Assistant within the Division of Hospital Medicine at Washington University. She holds a B.S. in Biochemistry and received her Physician Assistant, Master of Medical Science degree from St. Louis University in 2023. She is currently a PA Fellow in the year-long Advanced Practice Clinician (APC) Hospital Medicine Fellowship at Washington University. Previous research interests include the antimicrobial potential of synthetic ion channels and exploring new disease-modifying targets in the pathogenesis of Alzheimer disease. She prioritizes patient education and safety and is dedicated to setting a high standard for patient care.

Lisa M. Gill, DNP, ANP
Nurse Practitioner
- Phone: 314-362-1700
- Fax: 314-362-9878
Lisa M. Gill, DNP, ANP, is an accomplished healthcare professional with a strong educational background. She holds a BSN from the University of Missouri-Columbia (1993), an MSN from Barnes-Jewish College of Nursing (2000), and a Doctor of Nursing Practice from the University of Missouri-Kansas City (2017). She has served as a DNP and ANP for Washington University/ Barnes-Jewish Hospital for 31 years. Lisa’s career philosophy centers on providing holistic care that meets the physical and emotional needs of patients, treating each individual with dignity. She is certified by the American Nursing Credentialing Center and licensed by the Missouri Board of Nursing. With expertise in nursing care for congestive heart failure patients, Lisa has presented her work at conferences, including “The Congestive Heart Failure Nurse Development Project” (2016) and “Improving Non-Cardiac Nurses’ Knowledge and Comfort Level in Congestive Heart Failure Patient Care” (2017).
Overall, Lisa M. Gill is dedicated to delivering excellent healthcare, prioritizing patient well-being and demonstrating compassion in her work.

Margo Girardi, MD, SFHM
Associate Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Margo Girardi, MD, SFHM, is an Associate Professor in Medicine, Core Clinical Faculty for the Internal Medicine Residency Program, and the Medical Director for the Inpatient Medicine Teaching Service (Firm 1). She has an interest in medical education, clinical operations, quality improvement, and physician wellness. She attends frequently on the inpatient medicine teaching service and medicine consult service, as well as caring for patients directly on the hospitalist service. Dr. Girardi has recently focused on diabetes care, and she is the recipient of a grant from the Barnes-Jewish Hospital Foundation for the development and implementation of SQ insulin protocols for DKA patients on medicine.

Tracey Godbold, MD
Assistant Professor of Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Tracey L. Godbold, MD, is an Assistant Professor of Medicine in the Division of Hospital Medicine at Washington University School of Medicine in St. Louis. She attends on a variety of inpatient clinical services and teaching rotations, including the bone marrow transplant service, the General Medicine Inpatient teaching service (FIRM medicine), and the Procedure Team. She also enjoys caring for patients directly on the general inpatient hospitalist service and serving as a consulting physician at the Rehabilitation Institute of St. Louis (TRISL). Her clinical interests include Point-of-Care Ultrasound (POCUS) for clinical diagnosis and procedural management, high-value inpatient care, and teaching resident physicians.

Katherine Goodenberger, MD
Instructor in Medicine
- Phone: 314-362-1700
- Fax: 314-362-9878
Dr. Katherine (Katie) Goodenberger joined the Division of Hospital in July 2024. She graduated from Washington University with a bachelor’s degree and pursued a graduate degree in biological anthropology in New York. In her previous career, she studied early primate evolution through the fossil record, conducting fieldwork in Kenya and Wyoming. She also taught human gross anatomy to medical and dental students. After deciding to pursue medicine, she obtained a post-baccalaureate premedical certificate at Washington University and worked as a research assistant in the Division of Infectious Diseases. She then attended Washington University School of Medicine as a Distinguished Student Scholar and Danforth Scholar. As a medical student, she served on multiple curriculum committees and the Committee on the Oversight of Medical Education. She completed her Internal Medicine Residency at the University of Michigan School of Medicine in 2024, focusing her research on socioeconomic determinants of chronic lung disease outcomes. She received recognition from the American Thoracic Society for her work.