title: Colicinogeny of O157:H7 enterohemorrhagic Escherichia coli and the shielding of colicin and phage receptors by their O-antigenic side chains.
abstract: Twenty O157:H7 enterohemorrhagic Escherichia coli strains from patients with different clinical conditions were tested for colicinogeny and the presence of Verotoxin (VT) genes. From bloody diarrhea cases, 7/8 isolates and from hemolytic uremic syndrome cases 3/5 isolates all synthesized what appeared to be colicin D. The remaining strains, which included 7 from asymptomatic sources, were noncolicinogenic. The plasmid determining the colicin was found to be 1.4 kb larger than the 5.2-kb pColD. The colicin D protein had a molecular weight of about 90,000, whereas the O157 colicin was 87,000. The plasmid was designated pColD157 to reflect these differences. Of O157:H7 isolates 17/20 had genes for both of the Verotoxins VT1 and VT2, and the remaining 3/20 for VT1 only. There was no correlation between the presence of VT determinants and colicinogeny or symptoms. The O157:H7 strains exhibited significant resistance to other colicins and bacteriophages.
authors.affiliation: Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada.
authors.forename: D E
authors.initials: DE
authors.lastname: Bradley
authors.forename: S P
authors.initials: SP
authors.lastname: Howard
authors.forename: H
authors.initials: H
authors.lastname: Lior
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology*; D001427:Bacterial Toxins / Q000235:genetics; D003086:Bacteriocin Plasmids; D003087:Colicins / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology; D003090:Coliphages / Q000276:immunology; D003967:Diarrhea / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D006463:Hemolytic-Uremic Syndrome / Q000382:microbiology; D006801:Humans; D008970:Molecular Weight; D019081:O Antigens; D022622:Shiga Toxin 1; D013045:Species Specificity
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D003087:Colicins; D019081:O Antigens; D022622:Shiga Toxin 1