title: Distribution of uropathogenic virulence genes in Escherichia coli isolated from patients with urinary tract infection.
abstract: BACKGROUND
  Escherichia coli is the predominant pathogen causing urinary tract infection (UTI), the most common bacterial infectious disease encountered in clinical practice, accounting for significant morbidity and high medical costs. The severity of UTI produced by E. coli is due to the expression of a wide spectrum of virulence factors. In this study we evaluated the role of E. coli virulence determinants in the pathogenesis of UTI.
  
  
  METHODS
  A total of 90 uropathogenic E. coli strains were screened by PCR for the prevalence of seven virulence genes encoding type 1 fimbriae (fimH), pili associated with pyelonephritis (pap), S and F1C fimbriae (sfa and foc), afimbrial adhesins (afa), cytotoxic necrotizing factor (cnf), hemolysin (hly), and aerobactin (aer).
  
  
  RESULTS
  The prevalence of genes coding for fimbrial adhesive systems was 68% for fimH, 41% for pap, and 34% for sfa/foc. The operons coding for afa afimbrial adhesins were identified in 20% of strains. The hly and cnf genes coding for toxins were amplified in 19% and 3% of strains, respectively. A prevalence of 52% was found for the aer gene. The various combinations of detected genes were designated as virulence patterns. The strains isolated from hospitalized patients displayed a great diversity of gene associations compared to those isolated from ambulatory patients.
  
  
  CONCLUSIONS
  Our study showed that investigation of the bacterial pathogenicity associated with UTI may contribute to a better medical intervention.
authors.affiliation: Microbiology and Immunology Department, UR02SP13, Farhat Hached Teaching Hospital, Av. Ibn el Jazzar, 4000, Sousse, Tunisia.
authors.forename: Mouna
authors.initials: M
authors.lastname: Tarchouna
authors.forename: Asma
authors.initials: A
authors.lastname: Ferjani
authors.forename: Walid
authors.initials: W
authors.lastname: Ben-Selma
authors.forename: Jalel
authors.initials: J
authors.lastname: Boukadida
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003556:Cystitis / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009876:Operon; D011704:Pyelonephritis / Q000382:microbiology; D014552:Urinary Tract Infections / Q000382:microbiology*; D014774:Virulence / Q000235:genetics*; D055815:Young Adult
chemical_list: D029968:Escherichia coli Proteins