Detection of Pap, Sfa and Afa Adhesin-Encoding Operons in Uropathogenic Escherichia Coli Strains: Relationship With Expression of Adhesins and Production of Toxins

Res Microbiol. 1997 Dec;148(9):745-55. doi: 10.1016/s0923-2508(97)82450-3.


A total of 243 Escherichia coli strains isolated from patients with urinary tract infections (UTI) were investigated for the presence of pap, sfa and afa adhesin-encoding operons by using the polymerase chain reaction. It was found that 54%, 53% and 2% of the strains exhibited the pap, sfa and afa genotypes, respectively. Pap+ and/or sfa+ strains were more frequent in cases of acute pyelonephritis (94%) than in cases of cystitis (67%) (P < 0.001) and asymptomatic bacteriuria (57%) (P < 0.001). The pap and/or sfa operons were found in 90% of strains expressing mannose-resistant haemagglutination (MRHA) versus 37% of MRHA-negative strains (P < 0.001). The presence of pap and sfa operons was especially significant in strains belonging to MRHA types III (100%) (without P adhesins) and IVa (97%) (expressing the specific Gal-Gal binding typical of P adhesins). Both pap and sfa operons were closely associated with toxigenic E. coli producing alpha-haemolysin (Hly+) and/or the cytotoxic necrotizing factor type 1. There was an apparent correlation between the pap and sfa operons and the O serogroups of the strains. Thus, 93% of strains belonging to O1, O2, O4, O6, O7, O14, O15, O18, O22, O75 and O83 possessed pap and/or sfa operons, versus only 32% of strains belonging to other serogroups (P < 0.001). The results obtained in this study confirm the usefulness of our MRHA typing system for presumptive identification of pathogenic E. coli exhibiting different virulence factors. Thus, 85% of strains that possessed both pap and sfa adhesin-encoding operons showed MRHA types III or IVa previously associated with virulence of E. coli strains that cause UTI and bacteraemia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Escherichia coli / biosynthesis
  • Adhesins, Escherichia coli / genetics*
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Bacterial Proteins / biosynthesis*
  • Bacterial Toxins / biosynthesis*
  • Bacterial Toxins / genetics*
  • Bacteriuria / microbiology
  • Child
  • Child, Preschool
  • Cystitis / microbiology
  • Cytotoxins / biosynthesis*
  • Escherichia coli / genetics*
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / microbiology*
  • Escherichia coli Proteins*
  • Female
  • Fimbriae, Bacterial / genetics
  • Genotype
  • Hemolysin Proteins / biosynthesis*
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Operon*
  • Phenotype
  • Polymerase Chain Reaction
  • Pyelonephritis / microbiology
  • Urologic Diseases / microbiology*


  • Adhesins, Escherichia coli
  • Bacterial Proteins
  • Bacterial Toxins
  • Cytotoxins
  • Escherichia coli Proteins
  • Hemolysin Proteins
  • Hlya protein, E coli
  • cytotoxic necrotizing factor type 1