Design, Synthesis, and Evaluation of Cephamycin-Based Antisporulation Agents targeting Clostridioides difficile

With the aim of discovering small molecule inhibitors of the sporulation process in Clostridioides difficile, we prepared a series of C-7 α-(4-substituted-1H-1,2,3-triazol-1-yl)acetamide analogues of cefotetan, a known inhibitor of the C. difficile sporulation-specific protein target CdSpoVD. These analogues were evaluated using both in vitro binding assays with CdSpoVD and antisporulation assays against C. difficile. Further design concepts were aided utilizing the predicted docking scores (DS) using both AlphaFold (AF) models, and a crystal structure of the CdSpoVD protein (PDB 7RCZ). Despite being 1 order of magnitude more potent as a sporulation inhibitor than cefotetan, in vivo studies on compound 6a in a murine-model of C. difficile infection demonstrated comparable spore shedding capabilities as cefotetan. Importantly, compound 6a had no concerning broad spectrum antibacterial activities, toxicity, or hemolytic activity and thus has potential for further drug development.