Thomas G. Mitchell, PhD – Biography

Faculty and Research

Thomas G. Mitchell, PhD
Associate Professor Emeritus

research • biography •  publications


For a junior high school county science fair project, Tom Mitchell evaluated a chromogenic medium designed to recognize Candida albicans by its production of a pink colony. The medium did not perform well, but Mitchell was hooked on microbiology and mycology. As an undergraduate at the University of North Texas, he worked four years as a laboratory assistant and instructor for Professor James McBryde, PhD, who taught courses in botany and bacteriology and inspired an extraordinary number of students to careers in microbiology and medicine. After earning his BA in biology and chemistry in 1963, Mitchell worked for three years as a research technician in the Department of Microbiology and Immunology at Tulane University School of Medicine. As one of his projects, pursuing a new report at the time, he collected avian excreta from the cages of a variety of exotic birds at Audubon Zoo in New Orleans and isolated Cryptococcus neoformans and other yeasts. Mitchell subsequently entered the doctoral program in the same department and earned his PhD in 1971. He was mentored by Lorraine Friedman, Ph.D., with whom he investigated the phagocytosis of C. neoformans by Lewis rat peritoneal macrophages. By studying with Dr. Friedman, Mitchell became a academic descendent of the first generation of medical mycologists and established an unforeseen connection to Duke University.

Dr. Friedman earned her doctorate at Duke University under the direction of Norman F. Conant, PhD, who was James B. Duke professor and chair of Microbiology and Immunology. Dr. Conant had obtained his doctorate at Harvard University and did postdoctoral work in Paris with Raimond Sabouraud, MD, who is recognized as the founder of medical mycology. Dr. Conant became a pioneer in medical mycology and established the discipline in the United States. During his career, Dr. Conant, along with a small number of other investigators (e.g., Rhoda Benham at Columbia, Charles E. Smith at Stanford, Arturo Carrion in Puerto Rico, Chester Emmons at the NIH, Pablo Negroni in Argentina and G.C. Ainsworth in England), comprised the first generation of medical mycologists. Dr. Conant co-authored several editions of the Manual of Clinical Mycology, which was the seminal text for this new discipline. He taught the Duke Summer Mycology Course from 1948 until he retired in 1973, directed numerous dissertations and supervised many others who came from all parts of the world to learn about medical fungi. To some degree, he influenced every medical mycologist who was trained prior to 1970. The second generation of eminent medical mycologists who studied with Dr. Conant included Drs. Libero Ajello, Margarita Silva-Hutner, Howard Larsh, Morris Gordon, and of course, Lorraine Friedman. After leaving Duke, Dr. Friedman supervised or co-mentored the doctoral dissertations of a number of prominent medical mycologists, including George S. Kobayashi, Donald Greer, Judith E. Domer, Angela Restrepo, and Jim E. Cutler. Her orbit at Tulane provided an inspiring and heady atmosphere for medical mycology, and Mitchell was fortunate to have been there.

For his postdoctoral fellowship, Mitchell joined the laboratory of Paul G. Quie, M.D., in pediatrics at the University of Minnesota Medical School, and investigated the chemotaxis and phagocytosis of C. albicans by human neutrophils. In September 1974, Mitchell was recruited to the Department of Microbiology and Immunology at Duke University Medical Center, completing a circle in the lineage of medical mycologists with ties to Duke. Charged with the daunting privilege of replacing Dr. Conant, Mitchell was appointed director of the Clinical Mycology Laboratory, assumed responsibility for teaching medical mycology in the medical and graduate schools, and established a basic research program supported by extramural funds.

Mitchell joined the ASM in 1969 and has been a continuous member for 40 years. His service for the ASM includes:

1982-1987 Editorial Board, Journal of Clinical Microbiology
1987-1988 Chair-Elect, Division F (Medical Mycology)
1988-1989 Chair, Division F (Medical Mycology)
1998 Chair, Nominating Committee, Division F (Medical Mycology)
2005 Chair, Nominating Committee, Division F (Medical Mycology)
2009-2012 Member, Nominating Committee, gioMerieux Sonnenwirth Leadership Award (ASM and AAM)

Mitchell also directed the Serology Laboratory of Duke Hospital from 1974 to 1982, and the Mycobacteriology Laboratory from 1987 to 1991. He rejuvenated the Duke Summer Mycology Course, which he taught annually from 1975 to 1992, and during this period, the course enjoyed a global reputation as the premier basic course in medical mycology. His research program has included studies of dimorphism in C. albicans, the structure and biological properties of the capsule of C. neoformans, the leukocyte chemotaxin produced by Blastomyces dermatitidis, and during the past decade, the population genetics of medical yeasts. In 1991, he ceded directorship of the Clinical Mycology Laboratory to devote more effort to research, as well as teaching. Beginning with his first year at Duke, Mitchell has taught medical mycology and served as laboratory instructor in the medical school course of microbiology, and since 1990, he has directed or co-directed this course.

Reflecting his interest in basic science medical education, he has been a long-standing member of the School of Medicine Curriculum Committee, Promotions Committee, the recent Curriculum Revision Committee, several LCME accreditation committees, and since 1990, director of the multidisciplinary Infectious Diseases Research Program for third-year medical students. Mitchell is director of the Duke University Molecular Mycology and Pathogenesis Training Program, editor of the local DUMRU News, and associate editor ofMedical Mycology. He is also a fellow of the American Academy of Microbiology (AAM). In 2004, he was presented with the Billy H. Cooper Award for excellence in clinical research, laboratory diagnostic procedures, and teaching. In 2009, he was elected a fellow of the American Association for the Advancement of Science (AAAS) in recognition of his accomplishments in applying population genetics to elucidate origins and evolution of fungal pathogens.