Severity of chronic infections depends on the amount of dietary sugar. Moria C. Chambers, Chloe Ota, Ilana Porges, Brian P. Lazzaro. Entomology, Cornell University, Ithaca, NY.

   Metabolic state impacts response to infection and vice versa. Discerning the patterns of metabolic-immune interaction will help us make better predictions about how manipulating host metabolism could improve patient outcomes. We infected Drosophila melanogaster with pathogens binned into two kinetic classes, acute and chronic, and tested whether dietary sugar content affected adult flies' defense against each class of infection in a predictable manner. We defined acute infection as infection that kills flies within a few days, while chronic infection produces a median time to death of greater than 5 days while sustaining high bacterial loads. During acute infections, amount of dietary sugar had no significant effect. In contrast, feeding flies a high sugar diet during chronic infections resulted in higher bacterial loads and reduced survival as compared to flies fed on a low sugar diet. Our interpretation is that metabolic or physiological alteration influences the severity of chronic infection by altering the host environment from the perspective of the pathogen, but that acute infections are comparatively unconstrained so subtle host physiological differences have no effect. We determined the importance of diet and metabolic regulation as related to the timing of infection using diet switch experiments and drug inducible RNAi knockdown of metabolic regulators. To the extent that infection kinetics associate with metabolic response and sensitivity, we can harness kinetic data to propose metabolic interventions to limit infection and manage symptoms.