| Infectious disease, even in today's world, is a major threat to public health. Rapid adaptation of pathogens to essentially every human environment has allowed the threat to persist. Our usage of antimicrobials has created a pandemic of antimicrobial resistant pathogens, especially in the healthcare environment. New disease sources have resulted from our settlement and disturbance of lands with microorganisms that didn't necessarily coevolve with humans. For many reasons, human behaviors coupled with rapid pathogen evolution have sustained and will continue to sustain the threat of infectious disease. However, understanding the evolutionary histories and capacities of pathogens is important to counteract the impact of disease. This dissertation considers ways in which understanding pathogen evolution has led to advances in molecular epidemiology and pathogen diagnostics, and presents examples in two very different pathogens, Klebsiella pneumoniae and Coccidioides. First is a focus on one of the most critical multidrug resistant organisms currently plaguing our healthcare systems, K. pneumoniae. One chapter presents the global molecular epidemiology of K. pneumoniae strain ST258, the most important of the multidrug resistant strains, describing its emergence and worldwide dissemination and several adaptive traits. A second chapter presents a next-generation diagnostic tool for surveillance of high-risk K. pneumoniae strains in patients in the healthcare environment. Lastly is a review of the current state of knowledge of Coccidioides, an endemic fungal organism for which incidental human infection results in disease, and reveals our need for much more study of its evolution. This dissertation concludes with a high-level vision of the future direction of the molecular epidemiology and diagnostics for each of these pathogens. |
