Anti-inflammatory properties of butyrate-producing atypical Escherichia coli in a murine colitis model

Inflammatory bowel disease (IBD) is a chronic refractory in-testinal inflammatory disorder and its pathogenesis is related with several factors including genetic, environmental, micro-biota, and immune response, but remains largely unknown. In recent decades, gut microbiota composition and function have become a relevant aspect of IBD pathogenesis and expected promising therapeutic options including probiotics and fecal microbiota transplantation.1-3 Yoon et al.4 found a novel com-mensal Escherichia coli strain named atypical E. coli (atEc), which demonstrated anti-inflammatory effect because of 1 additional catalase gene compared to typical E. coli.3,4 Also, the short-chain fatty acids produced by gut microbiota, such as acetate, propionate, and butyrate are expected to maintain in-testinal homeostasis.5,6 We hypothesized to design a novel bu-tyrate-producing recombinant atEc strain using a 2-plasmid system and demonstrate its anti-inflammatory effect in mu -rine colitis model.