Julie Pfeiffer, Ph.D., whose discoveries launched a new discipline of microbiology studying transkingdom interactions, has begun her new role as Chair of Microbiology.

Dr. Pfeiffer, who joined UT Southwestern as an Assistant Professor in 2006, has established herself as a highly respected scientist and leader, serving as Vice Chair of the Department since 2022 and as Interim Chair from February until her May 22 promotion to Chair. Her contributions at UTSW have been recognized with numerous honors that include the Edith and Peter O’Donnell Award in Science in 2019 from the Texas Academy of Medicine, Engineering, Science and Technology and UT Southwestern’s Excellence in Postdoctoral Mentoring Award in 2022.

Dr. Pfeiffer received her undergraduate degree at Miami University and earned her doctorate in microbiology and immunology from the University of Michigan. She then pursued postdoctoral studies at Stanford University.

“Her scientific expertise, multidisciplinary approach, and proven leadership record will continue the Department of Microbiology’s tradition of excellence and further elevate our institution as a national hub for discovery, collaboration, and innovation,” said W. P. Andrew Lee, M.D., Executive Vice President for Academic Affairs, Provost, and Dean of UT Southwestern Medical School.

In recent years, Dr. Pfeiffer’s research has largely centered on interactions between bacteria and viruses. For almost two decades, her investigations have been supported by federal and private grants from sources including the National Institutes of Health, the Howard Hughes Medical Institute, the Burroughs Wellcome Fund, the American Cancer Society, and the Pew Innovation Fund. She serves on the editorial boards of Science and Cell Host & Microbe and is Associate Editor of the Annual Review of Virology.

We spoke with the new Chair about her research, collaborations, and plans for the Department.

Much of your research has involved polio. Why focus on a virus that the world has been largely successful in eradicating?

People have been studying polio for over 100 years. It’s a simple, tractable system that you can leverage to ask tough questions. For example, when we became interested in studying the effects of gut microbiota on enterovirus infection, that’s a complicated question because the gut is complex. We needed a simple, tractable tool. Actually, we no longer work with polio; we destroyed all our stocks in the last year because the world eradication campaign is entering a new phase where increased biocontainment would be required to continue working with polio in the lab. We have an amazing research scientist in our lab who tracked down all our tubes of polio and destroyed them. That would have been difficult for me; it’s hard to destroy your life’s work.

What discoveries are you most proud of?

In 2011, we uncovered the importance of resident bacteria for viral infection. We were studying how polio disseminates from the intestine to the nervous system, and we found that the gut was a major barrier. We hypothesized that beneficial bacteria in the gut may protect the host and limit viral movement. However, when we treated mice with antibiotics to deplete bacteria, virus infection was inhibited instead of enhanced! It turned out that gut bacteria made the virus more infectious. We are continuing to study viral-bacterial interactions. One of our favorite projects now is studying two reovirus strains that differ by a single mutation; that one mutation flips whether bacteria help or hurt their abilities to infect the gut. We are using these strains as tools to better understand this phenomenon.

A lot of your work is driven by partnerships with bacteriologists. What’s special about UT Southwestern that makes these partnerships possible?

Collaborations are really important here. There’s an expectation that you’ll help others and they’ll help you. That attitude trickles down from the top: Michael Brown, M.D., and Joseph Goldstein, M.D., have always run a joint lab. These Nobel Prize winners are both on every paper, every grant. Many places prefer to give credit to individuals, but collaboration is something that’s celebrated here. We also have a high tenure rate at UT Southwestern, unlike some places where there are a limited number of tenure slots. If you are competing with others for tenure, why would you help your neighbor? Here, there’s room for everyone to succeed, so we elevate each other’s work.

What changes do you plan within the Department?

Things are already working really well; our labs are well funded, publishing well, and thriving in every way possible – I don’t want to change that. I do want to make some minor tweaks, a few small additions that could extend alliances even more. We’re starting a monthly faculty-only meeting where we can pitch crazy ideas to each other that may end up becoming collaborations or joint grants in the future. Also, we’re a small Department right now – we have only 10 primary faculty. When you have a group where great things are happening, you want to keep building it up. I want to expand our faculty. If it ain’t broke, don’t fix it, but let’s keep building our momentum.