Our long-term goal is to fully understand the effects of vancomycin on the Elizabethkingia and determine the full susceptibility of these organisms to antimicrobials and vancomycin combinations. Our central hypothesis is that vancomycin demonstrates poor activity against Elizabethkingia and that vancomycin-resistance readily emerges. In spite of our central hypothesis, based on literature, it remains possible that vancomycin-antimicrobial combinations act in synergy to inhibit or kill Elizabethkingia.To investigate our hypotheses, in specific aim 1, we will determine the antimicrobial susceptibility of a collection of characterized Elizabethkingia species, using standard minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays, perform vancomycin challenge assays, and ascertain if vancomycin-antibiotic combinations demonstrate synergy.We also hypothesize that mutations in vancomycin-resistant mutants will occur in genes that affect vancomycin permeability, peptidoglycan biosynthesis and/or DNA repair and that the mutant transcriptomes will reflect alterations in these processes. To test this hypothesis in specific aim 2, we will isolate vancomycin-resistant mutants and these mutants will be completely sequenced by our collaborator Dr. Nicholson at the CDC, and all mutations will be identified. Select mutants will then be subjected to RNAseq analysis in order to investigate alterations in the transcriptome that can reveal the identity of metabolic shifts that contribute to the vancomycin resistance mechanism(s).