Citrobacter rodentium (CR) is an attaching-effacing enteropathogen which infects mice and causes intestinal inflammation. The CR infection model is appropriate for investigating host-pathogen interactions in the gut and understanding the pathogenesis of human inflammatory bowel diseases. Peptidyl arginine deiminase-4 (PAD4) is an enzyme required for the generation of neutrophil extracellular traps (NETs), which can provide antimicrobial effects during the host innate immune response; however, the role of PAD4 against gastrointestinal (GI) infection is largely unknown.