title: Acquisition of stcE, a C1 esterase inhibitor-specific metalloprotease, during the evolution of Escherichia coli O157:H7.
abstract: Escherichia coli O157:H7 is a source of foodborne illness, causing diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome. E. coli O157:H7 secretes, via the etp type II secretion system, a metalloprotease, StcE, that specifically cleaves the serpin C1 esterase inhibitor. We determined by hybridization techniques the prevalence of stcE and etpD, a type II secretion gene, among diarrheagenic E. coli strains. stcE and etpD are ubiquitous among the O157:H7 serotype and are found in some enteropathogenic E. coli O55:H7 strains but are absent from other diarrheagenic E. coli. stcE was acquired on a large plasmid early in the evolution of E. coli O157:H7, before the inheritance of the Shiga toxin prophage. Other plasmidborne virulence factors, such as ehxA, katP, and espP, were acquired later by the enterohemorrhagic E. coli 1 complex in a stepwise manner. These data refine the sequential model of E. coli O157:H7 evolution proposed elsewhere.
authors.affiliation: Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Wyndham W
authors.initials: WW
authors.lastname: Lathem
authors.forename: Tessa
authors.initials: T
authors.lastname: Bergsbaken
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Witowski
authors.forename: Nicole T
authors.initials: NT
authors.lastname: Perna
authors.forename: Rodney A
authors.initials: RA
authors.lastname: Welch
mesh_terms: D003174:Complement C1 Inactivator Proteins / Q000378:metabolism; D003967:Diarrhea / Q000382:microbiology; D019453:Escherichia coli O157 / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D019143:Evolution, Molecular; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D012703:Serotyping
chemical_list: D003174:Complement C1 Inactivator Proteins; D029968:Escherichia coli Proteins; D008666:Metalloendopeptidases; C465555:StcE protein, E coli