title: Correlation between virulence factors and in vitro biofilm formation by Escherichia coli strains.
abstract: The ability of 15 Escherichia coli strains to form biofilms on polystirene plates was studied. The strains were serotyped, and their phenotypic expression of surface virulence factors (VFs), and antibiotic susceptibility was also determined. Moreover, 30 VFs-associated genes were analysed, including 15 adhesins (papC, papG and its three alleles, sfa/focDE, sfaS, focG, afa/draBC, iha, bmaE, gafD, nfaE, fimH, fimAvMT78, agn43, F9 fimbriae and type 3 fimbriae-encoding gene clusters), four toxins (hlyA, cnf1, sat and tsh), four siderophore (iron, fyuA, iutA and iucD), five proctetins/invasion-encoding genes (kpsM II, kpsMT III, K1 kps variant- neuC, traT and ibeA), and the pathogenicity island malX and cvaC. Morphological appearance and thickness of biofilms of two strong and three weak biofilm producers were also studied by confocal laser scanning microscopy (CLSM). Seven strains were classified as strong biofilm producers and the remaining eight strains were regarded as weak biofilm producers. Mannose-resistant haemagglutination was the only phenotypically expressed surface virulence factor more frequently found in the strong biofilm group. Five virulence-associated genes were more common (p<0.05) in strong biofilm producers: papC and papG alleles, sfa/focDE, focG, hlyA and cnf1. CLSM images showed irregular biofilms with projections at the top mainly in strong biofilm.
authors.affiliation: Department of Medical Microbiology and Antimicrobial Chemotherapy, Fundación Jiménez Díaz-Capio, Madrid, Spain.
authors.forename: Plínio
authors.initials: P
authors.lastname: Naves
authors.forename: Gema
authors.initials: G
authors.lastname: del Prado
authors.forename: Lorena
authors.initials: L
authors.lastname: Huelves
authors.forename: Matilde
authors.initials: M
authors.lastname: Gracia
authors.forename: Vicente
authors.initials: V
authors.lastname: Ruiz
authors.forename: Jorge
authors.initials: J
authors.lastname: Blanco
authors.forename: Ghizlane
authors.initials: G
authors.lastname: Dahbi
authors.forename: Miguel
authors.initials: M
authors.lastname: Blanco
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Ponte
authors.forename: Francisco
authors.initials: F
authors.lastname: Soriano
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D018441:Biofilms / Q000254:growth & development*; D004926:Escherichia coli / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D014774:Virulence / Q000235:genetics / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors