title: [Virulence factors and 0 serogroups of Escherichia coli as a cause of community-acquired urinary infections].
abstract: BACKGROUND
  The aim of this study was to determine the virulence factors and 0 serogroups of E. coli strains that cause community acquired urinary tract infections (UTI).
  
  
  METHODS
  We examined 103 E. coli strains isolated from the urine of patients with UTI. The following virulence factors were investigated using phenotypic techniques: the alpha-haemolysin (Hly), the cytotoxic necrotizing factor type 1 (CNF-1) and the mannose-resistant haemagglutination (MRHA) types III, IVa and IVb expressed by P fimbriated E. coli. Serotyping of 0 antigen was carried out by means of a microtechnique using 163 antisera.
  
  
  RESULTS
  Fifty-five (53%) of the 103 E. coli strains examined showed some of the virulence factors investigated in this study; 41% of the strains were Hly+, 28% were CNF-1+ and 48% expressed MRHA types III, IVa or IVb. The uropathogenic strains characterized belonged to 27 different 0 serogroups. However, 68% were from one of 10 serogroups (01, 02, 04, 06, 09, 018, 027, 073, 075 and 077) and 36% were from one of only 3 serogroups (02, 04 and 06). Furthermore, the virulence factors were concentrated in strains belonging to the 3 serogroups most frequently detected. Thus, 36 (97%) of the 37 strains of these 3 serogroups showed virulence factors, versus only 19 (29%) of 66 belonging to other serogroups (p < 0.001).
  
  
  CONCLUSIONS
  Our results support the special pathogenicity theory and suggest that many cases of community acquired UTI may be caused by a limited number of uropathogenic E. coli strains that produce toxins (Hly+ and/or CNF-1+) and possess P fimbriae or P-related adhesins (with MRHA types III, IVa or IVb), and that usually belong to 02, 04 and 06 serogroups.
authors.affiliation: Departamento de Microbiología y Parasitología, Facultad de Veterinaria, Universidad de Santiago.
authors.forename: M
authors.initials: M
authors.lastname: Blanco
authors.forename: J
authors.initials: J
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: I
authors.initials: I
authors.lastname: Abalia
authors.forename: E
authors.initials: E
authors.lastname: Rodríguez
authors.forename: J R
authors.initials: JR
authors.lastname: Bilbao
authors.forename: A
authors.initials: A
authors.lastname: Umaran
mesh_terms: D017714:Community-Acquired Infections / Q000382:microbiology; D004926:Escherichia coli / Q000145:classification* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D012703:Serotyping; D014552:Urinary Tract Infections / Q000382:microbiology*; D014774:Virulence
vernacular_title: Factores de virulencia y serogrupos 0 de Escherichia coli causantes de infecciones urinarias comunitarias.