Enterobacteriales (more information below) Gammaproteobacteria Facultatively anaerobic, gram-negative rods Peritrichously flagellated if motile Inhabit the intestinal tracts of humans and other animals Fimbriae that help them to adhere to surfaces or mucous membranes Sex pili for reproduction: help to transfer bacteria resistance Produce bacteriocins that cause the lysis of related bacteria, which may help maintain the ecological balance in the intestines
