Targeted eradication of pathological bacteria from the intestinal ecosystem has a great promise as precision medicine to restore the homeostasis of gut microbiota in chronic inflammatory bowel disease (IBD). Therapeutic agents that target pathogen-specific virulence factors (i.e. virulence inhibitors) may have a key role in these treatment strategies, as they have a uniquely tailored activity spectrum that leaves beneficial commensal bacteria unaffected. However, there are also concerns that resistance against virulence inhibitors can readily evolve akin to antibiotic resistance, and consequently, altered bacterial virulence may compromise natural immunity. Addressing this issue is especially crucial, since inflammation coupled with dysbiosis of the intestinal microbiome contributes to pathogen evolution by horizontal gene transfer, a process that frequently involves virulence factors. My H-CEMM research project has two interconnected goals. First, we aim to provide an experimental platform that investigates horizontal gene transfer-mediated resistance evolution against virulence inhibitors. Uniquely, this approach will assess the virulence inhibitor resistome from the intestinal microbiomes of IBD patients by systematically screening for resistance phenotypes using various models of bacterial infections. Second, we will use the technology to better understand some of the most worrying biological issues in the field: Which genes provide resistance for the targeted bacteria against virulence inhibitors in a dysbiotic gut microbiome? Does resistance to virulence inhibitors affect virulence in the absence of the drug? Does the popular dogma hold that resistance evolution against virulence inhibitors is less likely than against conventional antibiotics? The expected results will provide a predictive tool for drug developers to better understand how to design safer and more resistant-proof anti-virulence treatment strategies, and will provide an example of how synthetic biology can advance research towards a new era of precision medicine.