This application is a new submission for our Microbial Pathogenesis and Genomics training program, whichwas previously supported by a T32 from 2006-2016. We are requesting support for five predoctoral traineesper year. The program, which is based at the University of Pennsylvania and Children's Hospital ofPhiladelphia and is located on a single contiguous campus, includes twelve laboratories directed by well-established principle investigators and three 'junior investigators', who are newly appointed assistantprofessors. Based on the success of the previously funded program, this T32 will enable us to continue torecruit some of the best and brightest trainees from a talented pool at Penn and from a vibrant biomedicalenvironment that offers a large number of outstanding research opportunities for students. The organizedtraining mission of this T32 has helped our efforts to collaborate and interact more effectively as a group; ourtrainers have several joint NIH grants, numerous joint publications, and a network of robust collaborations thatinvolve our trainees. Our research in progress meetings and seminars within the microbiology program havehelped spur the rapid growth of exciting, collaborative work in bacterial pathogenesis, microbialimmunopathogenesis, and bacterial metagenomics, with institutional support for deep-sequencing facilities,bioinformatics, and a germ-free mouse core playing important roles in these efforts. These resources havebeen expanded to the new Penn-CHOP Microbiome Program, which will be a major focal point for newresearch and collaborations within our T32. The retention rate of our previously funded program was perfect;no trainee left the program prematurely over the 10 years of funding. In addition, all of our former traineeshave continued to work in Microbiology or closely related fields involving infectious diseases. Five of ourprevious trainees have obtained tenure-track faculty positions ? all at major universities. The researchopportunities provided by the trainers in this program coupled with strong institutional commitment and anextensive and well-organized training program will continue to provide excellent predoctoral training inmicrobial pathogenesis and genomics.