Detection of Virulent Burkholderia mallei

DESCRIPTION (provided by investigator): Our objective is to develop discriminating diagnostic assays to Burkholderia mallei, the cause of glanders. It is an understudied biothreat agent that has been used by our adversaries. We are vulnerable to this agent because there is no rapid detection assay, no distinctive diagnostic signs, and a short incubation period of days. In addition there is no vaccine, no infection-induced protective immunity, and only limited reliable in vivo data on antibiotic efficacy. We believe these gaps can be filled expeditiously and economically after identifying relevant nucleotide sequence and antigenic targets with a novel combination of complete comparative genomic and proteomic approach using phenotypically characterized B. mallei strains in the natural host- equine or human. The phenotype of virulent or avirulent is based on their ability to kill or produce life threatening disease in the host. Comparison of the genomic sequences of a set of virulent strains to avirulent (attenuated) strains can identify unique genetic markers and regions responsible for the virulence of this organism. We will perform parallel proteomic (mass spectrometry and peptide mapping) studies which will provide complementary and convergent data to see if the gene of interest is being expressed and at a level of biologic significance. Our initial focus is on diagnostics. It is very important to identify a virulent strain in the patient and the environment to mitigate against life-threatening infections and to mount an emergency response. A response to a near neighbor microbe or an avirulent strain will result in an unnecessary and astronomically expensive response. Based on the data, we will use unique nucleotide signatures for a DNA based test. Proof of principle for Phase 1 will be to test the ability of designed primers to detect and discriminate the virulent organism from the avirulent strain and near neighbors. A second goal will be to test this in clinical samples. In Phase 2 we can perform biologic experiments to further develop and validate identified targets for diagnostics in several platforms with which we have practical experience and those which may be newly available before Phase 2 begins. In Phase 2 we will also develop the immuno-based assays.