Current clinical practice in infectious diseases heavily relies on in vitro analysis of bacterial susceptibility and on population-based drug pharmacokinetics. Microbial antibiotic susceptibility, however, depends strongly on the metabolic and physiological state of the cell, which in turn is governed by the chemical and physical microenvironment. Our vision is to improve patient care by understanding host-drug-pathogen interaction in vivo. We study pathogen resistance and persistence at the site of infection (e.g., bone) as well as adaptive and maladaptive host responses in both animal models and human patients. These are integrated to develop personalized therapeutics.