title: Genes related to long polar fimbriae of pathogenic Escherichia coli strains as reliable markers to identify virulent isolates.
abstract: Lpf (stands for long polar fimbriae) is one of the few adhesive factors of enterohemorrhagic Escherichia coli O157:H7 associated with colonization of the intestine. E. coli O157:H7 strains possess two lpf loci encoding highly regulated fimbrial structures. Database analysis of the genes encoding the major fimbrial subunits demonstrated that they are present in commensal as well as pathogenic (both intestinal and extraintestinal) E. coli strains and in Salmonella strains and that the lpfA1 and lpfA2 genes are highly prevalent among LEE (locus of enterocyte effacement)-positive E. coli strains associated with severe and/or epidemic disease. Further DNA sequence analysis of the lpfA1 and lpfA2 genes from different attaching-and-effacing E. coli strains has led us to the identification of several polymorphisms and the classification of the major fimbrial subunits into distinct variants. Using collections of pathogenic E. coli isolates from Europe and Latin America, we demonstrated that the different lpfA types are associated with the presence of specific intimin (eae) adhesin variants and, most importantly, that they are found in specific E. coli pathotypes. Our results showed that the use of these fimbrial genes as markers, in combination with the different intimin types, resulted in a specific test for the identification of E. coli O157:H7, distinguishing it from other pathogenic E. coli strains.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, 77555-1070, USA. altorres@utmb.edu
authors.forename: Alfredo G
authors.initials: AG
authors.lastname: Torres
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: Patricio
authors.initials: P
authors.lastname: Valenzuela
authors.forename: Terry M
authors.initials: TM
authors.lastname: Slater
authors.forename: Shilpa D
authors.initials: SD
authors.lastname: Patel
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Cecilia
authors.initials: C
authors.lastname: López
authors.forename: Ximena Fernández
authors.initials: XF
authors.lastname: Barriga
authors.forename: Jesús E
authors.initials: JE
authors.lastname: Blanco
authors.forename: Tânia A T
authors.initials: TA
authors.lastname: Gomes
authors.forename: Roberto
authors.initials: R
authors.lastname: Vidal
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005060:Europe; D010861:Fimbriae, Bacterial / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D007843:Latin America; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014481:United States; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D005819:Genetic Markers; D037521:Virulence Factors