Acinetobacter baumannii (Ab) is an emerging pathogen that causes primary and opportunistic infections, and is a serious concern in the hospital and battlefield setting. This organism has significant intrinsic resistance to antibioticsas well as an ability to quickly acquire new resistance. Additionally, Ab can persist in a desiccated state on fomites, making disinfection and management of nosocomial infections particularly troublesome. The goal of this research proposal is to find unexploited therapeutic approaches by elucidating the role of uncharacterized genes of Ab in this organism's mechanisms of pathogenesis, resistance, and persistence. Three projects will be established to 1) use a genomic approach to broadly identify the role of uncharacterized genes (Colin Manoil, Project 1 Director) 2) determine the role of envelope integrity with regard to bacterial viability (Sam Mille, PI/PD, Project 2 Director), and use expression analysis to identify genes and sRNAs of unknown function associated with drug, disinfectant, and desiccation tolerance (Carrie Harwood, Project 3 Director). The work of the Center will be supported by an Administrative Core (Core 1, John Kemner Core Leader), a Protein Interaction Technology Core (Jim Bruce Core 2 Director Leader), and a Data Dissemination/Resource Management Core (Mitch Brittnacher, Core 3 Director).
This proposal describes a center created to investigate the role of previously uncharacterized genes of Acinetobacter baumannii in its ability to cause human disease. This pathogen is recently emerging as a persistent and multi-drug resistant agent, and new approaches to managing infection are needed. The research goals of this center are to provide such alternate avenues for the development of countermeasures. Project 1: Assigning function of unknown genes of Acinetobacter baumannii by use of genetic analysis Project Leader (PL): Colin Manoil DESCRIPTION (as provided by applicant): Project 1 will identify and assign functions to conserved genes of unknown function in Acinetobacter baumannii, an emerging pathogen that causes hospital-acquired, antibiotic resistant infections. The project will focus on protein-coding genes that contribute to any of seven clinically relevant resistance traits. We hypothesize that such genes control the expression and activities of efflux pumps, membrane permeability determinants, inactivating enzymes, and stress responses. Genes required for resistance to four antibiotics, two biocides and desiccation will first be identified by genome-scale mutant screening using Tn-seq technology. A subset of the resistance genes of unknown function will then be characterized using a battery of genetic, genomic and proteomic approaches. The results will be interpreted in the context of current understanding of each trait in order to formulate potential molecular functions for the genes examined. Hypothesized functions will then be tested using approaches tailored to individual genes. PUBLIC HEALTH RELEVANCE: Acinetobacter baumannii has emerged in recent decades as an important agent of hospital-acquired infections throughout the world. The pathogen's emergence can be understood in large part by its high resistance to antibiotics, biocides and desiccation. The proposed studies will identify the gene functions responsible for several such resistance traits. The work should identify targets for drugs to enhance the efficacy of established antibiotics in treating Ab infections and for agents that decrease environmental persistence of the bacterium.