Alexis Mraz studies a bacterium most people never think about — but one that public health officials closely monitor. Legionella, which causes Legionnaires’ disease, is common in water systems, particularly in large buildings such as hospitals, nursing homes, and hotels. When inhaled in tiny water droplets, including mist from showers or medical equipment, the bacteria can cause a severe form of pneumonia.
Mraz, an associate professor of public health, has spent her career investigating why Legionella is so difficult to control and how building managers and water utilities can better protect people, especially those most vulnerable to infection. The problem, she says, is hidden inside plumbing systems.
“If you cut open an old pipe, it’s not smooth on the inside,” Mraz says. “There’s gunk.”
This slimy buildup, called a biofilm, is a living community of microbes wrapped in a sticky matrix that protects bacteria like Legionella from disinfectants and heat, often allowing them to survive treatment and rebound.
Considered an opportunistic pathogen, Legionella is widespread in water, but is most dangerous to people with weakened immune systems, particularly in health care settings. The bacteria thrive in warm water and complex plumbing systems with stagnant areas and uneven disinfectant levels. Because eliminating Legionella entirely is often unrealistic, Mraz’s work focuses on how to control it by keeping bacterial levels low enough to prevent disease.
By simulating water temperature, disinfectant levels, pipe design, and costs, Mraz’s earlier research and computer models helped identify practical strategies for reducing risk without creating new problems, such as scalding hazards or excessive operating expenses.
Now, as the winner of the 2026 Gitenstein-Hart Sabbatical Prize, she’ll have the focused time she needs to advance her hands-on research on Legionella. During a year-long sabbatical that will start in August, she will move deeper into laboratory research where she’ll grow biofilms under controlled conditions and study how Legionella responds to common treatments in combination with other water chemistry factors that the bacteria need to grow.
She will also analyze data from a previously canceled EPA-funded project examining trade-offs between controlling Legionella and limiting harmful disinfectant byproducts. The ultimate aim of her research is to translate complex science into clear, realistic guidance for utilities, hospitals, and building managers.
“I don’t want theoretical solutions that don’t work in real buildings,” Mraz says. “The goal is incremental, practical changes that actually reduce cases of Legionnaires’ disease.”
The Gitenstein-Hart Sabbatical Prize is made possible through the generosity of former TCNJ president R. Barbara Gitenstein and her husband Don Hart. Their endowed gift supports a stipend for a faculty member taking a full-year sabbatical, thereby allowing the awardee to focus more deeply on their scholarly work.
— Emily W. Dodd ’03