Title: Understanding the emergence and spread of antimicrobial resistance  

Abstract 
Understanding the emergence and spread of antimicrobial resistance is one of the grand challenge for global human health, but it is also a complex fundamental problem in evolutionary biology, concerning the response of populations experiencing stressful environmental conditions. My research explores the interaction between genomics and evolutionary fitness in antibiotic resistant organisms. Specifically, I am interested in commonalities between adaptation to different antibiotic compounds, and how fitness changes during sustained selection for resistance in environments containing antibiotics. I use experimental resistance evolution in Escherichia coli and other laboratory model organisms to observe how populations change when undergoing either natural selection or genetic drift. Combining data from experimental evolution, mutation accumulation, and fluctuation tests, I explore how the spectrum of spontaneous resistance mutations interacts with their effects on fitness, both in the presence and absence of antibiotics, to determine evolutionary outcomes. This work generates predictions about the adaptive dynamics of resistant populations facing fluctuations in effective population sizes, a common feature of microbial infections.