A new study published in Nature Communications has reported an increased abundance of Enterobacteriaceae in IL10−/− mice (IL-10 deficiency results in spontaneous and chronic colitis) compared with healthy controls. Results from Escherichia coli RNA sequencing in IL10−/− mice revealed an altered expression profile, which was attributed to intestinal adaptation. Moreover, inflammation and carcinogenesis appeared to modify the expression of tumour-promoting genes in the E. coli pks island (a region encoding polyketide-peptide genotoxins). The authors believe that inflammation in these mice underpins Enterobacteriaceae colonization and affects expression of genes related to tumour development.