Escherichia coli (/ˌɛʃɪˈrɪkiə ˈkoʊlaɪ/; commonly abbreviated E. coli) is a Gram-negative gammaproteobacterium commonly found in the lower intestine of warm-blooded organisms (endotherms). The descendants of two isolates, K-12 and B strain, are used routinely in molecular biology as both a tool and a model organism.
