Core 1 Administrative Core

Summary/Abstract Administrative Core #1 Resistance to our major antibiotics has been identified by the CDC as a major threat to the health and safety of the American public. Two of the highest threat pathogens are Carbapenem-Resistant Acinetobacter baumannii (CRAB) and Klebsiella pneumoniae (CRKP). Over the last decade, we have seen the emergence of novel resistance mechanisms that have limited the utility of the antimicrobials that have served as the backbone of our therapeutic armamentarium. This Proposal is a response by the call to action of the CDC, WHO and NIAID, with their RFA-AI-16-081, where new tools were developed to help identify new agents and, as importantly, under- stand, at the mechanistic level, how to translate combinations of agents to the clinic in order to maximize bacterial killing and suppress resistance emergence. In addition, there has been increasing awareness of organism state(s) such as tolerance/Non-Replicative Persister (NRP) Phenotype that allows these pathogens to evade the lethal action of antimicrobial therapy. This problem is not genotypically driven. It is important to gain insight into this phenomenon to allow us to design approaches that suppress the entry of organisms into this state and, if already present in a larger organism population, create dosage regimens that efficiently kill them. We also intend to examine the impact of time (as 4th dimension) on the expression of penicillin-binding proteins (PBP) and resistance mechanisms to develop optimal dosage regimens for serious infections with a high bacterial burden. This P01 will address these issues through three Projects and three Cores. Project #1 will examine CRAB and CRKP under pressure from antimicrobials alone and in combination. We have developed a very high dimensional mathematical model linking PBP occupancy patterns for combinations to rates and extent of kill and resistance emergence. Project #2 will examine the best and less good regimens in the Hollow Fiber infection model (HFIM) with the metrics of cell kill and resistance suppression. We will also look at metabolic states and expression of resistance mechanisms. In Project #3, we will study these regimens in two murine models of pneumonia, granulo- cyte-replete and granulocytopenic, to assess the impact of granulocytes on outcome. Both murine models and the HFIM will be independent, prospective validation studies for Project #1 and allow model refinement. The Cores will be the Administrative, Mechanistic Assay Core and Mathematical Modeling Core. The Administrative Core will serve as the overall data repository and clearing house. It will facilitate transfer of information and mutual communication amongst all Projects and Cores. It will also support monthly and yearly meetings (mostly electronic) for evaluation and planning purposes. The Mechanistic Assay Core provides drug assays, proteo- mics, whole genome sequencing, resistance assays, and flow cytometry (with sorting). Finally, the Mathematical Modeling Core will develop high dimensional models that will integrate the experimental data from all Projects and Cores to provide robust, optimal, and clinically relevant antibiotic dosage regimens against CRAB & CRKP.