Dissertation Title and Summary

 Relative Virulence and Toxin Production in Escherichia coli O157:H7

Foodborne outbreaks are a continuing global concern. Not only do these outbreaks increase the total disease and healthcare burden, but they also lead to food waste and economic repercussions due to the globalization of food production and export. Increased sanitation, regulation, and testing have helped lower the impact of foodborne outbreaks significantly, but we have hit a wall for some pathogens that still regularly cause outbreaks worldwide.

My dissertation focuses on one such bacterium called Shiga toxin-producing Escherichia coli (also known as STEC). E. coli has many different types, and some strains can even be beneficial to your gut health. However, STEC bacteria have caused quite a few deadly outbreaks over the years: a toxin produced by the bacterium can target the kidneys and lead to kidney failure and even death in some patients.

My work analyzes STEC isolated from different patients, and I study the different isolates from a genetic and molecular biology standpoint. While previous research has identified the major pathway of toxin production, it’s still not clear why some isolates make and/or release different amounts of toxin. I have found that along the multiple steps leading to toxin production, changes to key regulatory proteins in the pathway can impact the final toxin amount and/or release. These protein changes aren’t unique to the isolates I work with they can also be found in other patient isolates from national databases. Studying the differences between these patient isolates broadens our understanding of how STEC makes this deadly toxin and may allow us to make predictions about the novel STEC bacteria that will inevitably cause future deadly outbreaks.


Rama Atitkar is a doctoral candidate in the Emerging Infectious Diseases program at the Uniformed Services University. Her dissertation work focuses on the regulation of toxin in Escherichia coli O157:H7, which is an important cause of foodborne diarrheal disease. She is interested in science policy, particularly as it relates to global infectious disease inequities/disparities. Rama graduated with a Bachelor of Science in Cell Biology and Molecular Genetics from the University of Maryland, College Park in 2014. As an undergraduate, she volunteered with the Girls Excelling in Math and Science (GEMS) club of Prince George’s County to lead an after-school STEM enrichment program for girls at local middle schools. Rama is also a trained Indian Classical Bharatanatyam dancer, and has competed nationally with a variety of Indian dance teams since 2011.