C. difficile infection (CDI) has emerged as a significant public health threat worldwide. Toxins are major virulent factors of C. difficile. We are investigating C. difficile toxin-mediated signaling events, leading to production of pro-inflammatory mediators. We are developing preventive and therapeutic agents targeting toxins, pro-inflammatory mediators and C. difficile. We have established mouse and hamster models of CDI. We use multidisciplinary approaches in our research, including molecular biology/microbiology, cell biology, protein engineering, immunology, genome sequencing, flow cytometry and nano-particle delivery. Projects: 1) The roles of innate immunity and intestinal microbiome in the pathogenesis of CDI; 2) Signaling pathways of pro-inflammatory mediators and CDI; 3) Development of novel therapeutic /preventive agents against C. difficile; 4) Regulation of C. difficile toxin production; 5) Antibiotic resistance, epidemiology and whole-genome sequencing of C. difficile.