Victor DiRita, Ph.D.

Chairperson, Department of Microbiology & Molecular Genetics
Rudolph Hugh Endowed Professor, Department of Microbiology & Molecular Genetics

The DiRita lab studies biology and pathogenicity of bacteria that cause human disease. Three microbes we study extensively are Vibrio cholerae, the agent of human cholera, Campylobacter jejuni, a commensal of chickens that causes human illness, and Enterobacter spp. from hospital-acquired infections. Research questions are varied depending on the microbe, but in general we are interested in genetic regulatory mechanisms and metabolic requirements for fitness during infection. We also use small molecules to probe biological mechanisms, essentially using chemical biology to answer interesting questions and as a way to develop potential new therapeutic approaches.

In Vibrio we study a complex regulatory pathway that controls expression of cholera toxin and other key virulence traits. This regulatory system includes transcription factors that are localized to the inner membrane of the cell, which is an unusual place to find DNA binding/transcription activation proteins. For this work we use genetics, biochemistry, chemical biology, and superresolution imaging – the last approach done in collaboration with the lab of Julie Biteen at University of Michigan. We are also exploring metabolic traits that enable V. cholerae to grow to very high levels during infection.

Our work on C. jejuni focuses on two different outcomes of colonization in animals: commensal colonization in poultry, and damage-inducing inflammation in humans. We work extensively with chickens, uncovering mechanisms enabling high levels of colonization without disease. In contrast, as a model for human inflammatory outcomes after C. jejuni we use ferrets.

We are part of a consortium of investigators including Drs. Michael Bachman, Mark Anderson, and Harry Mobley at University of Michigan studying hospital-acquired microbes. Our group studies the “Carbapenem-resistant Enterobacteriaceae” (CRE). Enterobacter hormaechii is resistant to multiple antibiotics, and is a threat in health-care settings among others. We are using genomic and transcriptomic approaches to uncover its mechanisms of infection, which we aim to use as targets for developing new therapeutics against these microbes.