Super shedders of Escherichia coli O157:H7 have a unique fecal bacterial community structure. bovine gut metagenome

Escherichia coli O157:H7 is a major food borne human pathogen causing disease worldwide. Cattle are a major reservoir for this pathogen and those that shed E. coli O157:H7 at > log 4 per g feces have been termed “super-shedders”. A rich microbial community inhabits the mammalian intestinal tract, but it is not known if the structure of this community differs between super shedder cattle and their non-shedding pen mates. We hypothesized that the super-shedder state is a result of an intestinal dysbiosis of the microbial community and that a “normal” microbiota prevents E. coli O157:H7 from reaching the super shedding state. To address this question, we applied 454 pyrosequencing of bacterial 16S rRNA genes to characterize fecal bacterial communities from 22 animals originating from a Canadian feedlot: 11 super-shedders of E. coli O157:H7 (SS) and 11 E. coli O157:H7 negative non-shedders (NS).