title: Virulence factors and O groups of Escherichia coli strains isolated from cultures of blood specimens from urosepsis and non-urosepsis patients.
abstract: Ninety-six Escherichia coli strains isolated from cultures of blood specimens taken from both urosepsis patients (n = 48) and non-urosepsis patients (n = 48) were examined for the production of alpha-haemolysin (Hly) and cytotoxic necrotizing factor type 1 (CNF1), the expression of P-fimbriae and mannose-resistant haemagglutination (MRHA). Twenty-seven (56%) of the E. coli strains from urosepsis showed some of the virulence factors investigated, whereas only 15 (31%) of the strains associated with non-urosepsis possessed virulence factors (P < 0.05). By contrast, only 16% (P < 0.001) of the faecal isolates from healthy individuals were virulent. Of the bacteremic E. coli strains, 56 (58%) belonged to one of 8 serogroups (O1, O2, O4, O6, O8, O9, O18 and O83). Virulence factors were concentrated in strains belonging to serogroups O2, O4, O6, O18 and O83. Thus, 23 (72%) of the 32 strains of these 5 groups showed virulence factors, but only 19 (30%) of the 64 strains belong to other serogroups (P < 0.001). The majority of bacteremic O2, O4, O6 and O83 E. coli strains were Hly+CNF1+ and expressed P-fimbriae or MRHA type III, whereas the strains of serogroup O18 were Hly+CNF1- and had P-fimbriae or MRHA type III, whereas the strains of serogroup O18 were Hly+CNF1- and had P-fimbriae. We conclude that strains from urosepsis show more virulence factors than bacteremic strains isolated from non-urosepsis.
authors.affiliation: Departamento de Microbioloxía e Parasitoloxía Facultade de Veterinaria, Universidade de Santiago de Compostela.
authors.forename: M
authors.initials: M
authors.lastname: Blanco
authors.forename: J E
authors.initials: JE
authors.lastname: Blanco
authors.forename: M P
authors.initials: MP
authors.lastname: Alonso
authors.forename: J
authors.initials: J
authors.lastname: Blanco
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000032:analysis; D001427:Bacterial Toxins / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D003603:Cytotoxins / Q000032:analysis; D004926:Escherichia coli / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D029968:Escherichia coli Proteins; D010861:Fimbriae, Bacterial; D006388:Hemagglutinins / Q000032:analysis; D006460:Hemolysin Proteins / Q000032:analysis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D019081:O Antigens; D011135:Polysaccharides, Bacterial / Q000032:analysis; D018805:Sepsis / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology*; D012703:Serotyping; D013030:Spain / Q000453:epidemiology; D014552:Urinary Tract Infections / Q000150:complications / Q000453:epidemiology / Q000382:microbiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; D006388:Hemagglutinins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli; D019081:O Antigens; D011135:Polysaccharides, Bacterial; C060296:cytotoxic necrotizing factor type 1