PROJECT SUMMARY Despite recent emphasis on the microbiome, there are few skin microbiome studies in infants; even fewer have been performed in preterm infants. Currently, there is a significant gap in our knowledge of the normal evolution of the preterm infant skin microbiome from birth to an independent, site-specific cutaneous microbiome. Preliminary studies show that preterm infants have limited microbial diversity and different predominant cutaneous microbes compared to full-term infants. This lack of a robust, diverse skin microbiome may render preterm infants susceptible to pathogenic skin bacteria that cause disease, particularly neonatal sepsis. The research goals of this mentored career-development award are to: 1) characterize the establishment of the neonatal skin microbiome in a cohort of preterm infants from birth to 4 weeks and compare to demographic and clinical variables, 2) recruit a cohort of term infants to determine if the preterm infant skin microbiome is significantly different than term infants, and 3) analyze cultured pathogens with the skin microbiome in late-onset neonatal sepsis (LOS). Our methods represent a departure from the currently available studies, which provide opportunistic sampling of the neonatal skin microbiome rather than sampling at defined timepoints. This study will vertically-advance the field by sampling the preterm skin microbiome systematically after birth. The role of the skin microbiome in neonatal sepsis has also not been described, and the design of this study will provide a better understanding of changes in the skin microbiome before late onset sepsis. Together, these aims will provide insight into the normal and abnormal development of the preterm infant skin microbiome. Future studies will then leverage the neonatal skin microbiome via therapeutic and preventative strategies to lower the incidence of LOS. This K23 is the next logical step in the training program started under my KL2 award, and the final step in my transition to an independent physician scientist. This proposal describes mentored research and training activities designed to launch a novel neonatal skin microbiome research program, the first in the field of pediatric dermatology. Five training and career development goals, facilitated by my mentoring team, are required to accomplish this. These include: extend my understanding of research design, deepen my knowledge of microbiome and relevant laboratory science, gain working knowledge of statistics/bioinformatics (including advanced metagenomic analyses), learn to lead an independent laboratory, and expand my professional network within microbiome science. The University of Florida provides a rich environment with expertise in the neonatal microbiome and metagenomics, ideal to extend my previous work as I develop a novel neonatal skin microbiome research program. The resources at UF will be augmented by additional skin microbiome expertise and laboratory resources from Dr. Pam...