title: Determination of adhesin gene sequences in, and biofilm formation by, O157 and non-O157 Shiga toxin-producing Escherichia coli strains isolated from different sources.
abstract: Biofilm formation by Shiga toxin-producing Escherichia coli (STEC) has been associated with the expression of different adhesins (type 1 fimbria, curli, Ag43, Cah, and EhaA). In this study, biofilm formation and the presence of adhesin-related gene sequences were determined by PCR in 18 O157 strains and 33 non-O157 strains isolated from different sources (human, animal, food, and water). The expression of different adhesins was also assessed by reverse transcription-PCR (RT-PCR), Congo red agar plates, and mannose-sensitive hemagglutination (MSHA) assay. Biofilm formation occurred in 5/18 (28%) O157 STEC strains and 17/33 (51%) non-O157 STEC strains from different serotypes and sources, when the assays were performed at 28°C for 48 h. Among the non-O157 biofilm-producing isolates, 12/17 (71%) expressed type 1 fimbriae and 11/17 (65%) expressed curli and produced cellulose, while 8/17 (47%) were considered to be Ag43(+) by RT-PCR. Among O157 strains, a close correlation was observed between biofilm formation and expression of curli and cellulose. In non-O157 strains, it seems that, in addition to the presence of curli, the ability to form biofilm is associated with the presence of other factors such as type 1 fimbriae and autotransporter proteins, which may contribute to the persistence of these organisms in the environment.
authors.affiliation: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, Rua Botucatu, 862 3° andar, São Paulo, Brazil.
authors.forename: Franciele Tafarello
authors.initials: FT
authors.lastname: Biscola
authors.forename: Cecilia Mari
authors.initials: CM
authors.lastname: Abe
authors.forename: Beatriz Ernestina Cabilio
authors.initials: BE
authors.lastname: Guth
mesh_terms: D018830:Adhesins, Escherichia coli / Q000235:genetics* / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D003224:Congo Red / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D006386:Hemagglutination Tests; D006801:Humans; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054323:Shiga-Toxigenic Escherichia coli / Q000235:genetics* / Q000254:growth & development* / Q000302:isolation & purification; D013696:Temperature; D013997:Time Factors
chemical_list: D018830:Adhesins, Escherichia coli; D004269:DNA, Bacterial; D003224:Congo Red