Attachment of Shiga toxigenic Escherichia coli to stainless steel

The biofilm-producing abilities of potentially human-pathogenic serotypes of Escherichia coli from the ovine reservoir were studied at different temperatures and on different surfaces. A possible influence of the hydrophobicity of the bacterial cells, as well as the presence of two virulence factors, the Shiga toxin-encoding (Stx) bacteriophage and the eae gene, was also studied. A total of 99 E. coli isolates of serotypes O26:H11, O103:H2, and O103:H25 isolated from sheep feces were included. The results show that isolates of all three E. coli serotypes investigated can produce biofilm on stainless steel, glass, and polystyrene at 12, 20, and 37°C. There was a good general correlation between the results obtained on the different surfaces. E. coli O103:H2 isolates produced much more biofilm than those of the other two serotypes at all three temperatures. In addition, isolates of serotype O26:H11 produced more biofilm than those of O103:H25 at 37°C. The hydrophobicity of the isolates varied between serotypes and was also influenced by temperature. The results strongly indicated that hydrophobicity influenced the attachment of the bacteria rather than their ability to form biofilm once attached. Isolates with the eae gene produced less biofilm at 37°C than isolates without this gene. The presence of a Stx bacteriophage did not influence biofilm production. In conclusion, our results show that potentially human-pathogenic E. coli from the ovine reservoir can form biofilm on various surfaces and at several temperatures relevant for food production and handling.

Section: Discussionmentioning

confidence: 99%

Potentially Pathogenic Escherichia coli Can Form a Biofilm under Conditions Relevant to the Food Production Chain

Nesse

Sekse

Berg

et al. 2014

“…In contrast, other studies have found no such relationship (16,18), while further studies have suggested that individual strains may behave in unique manners with respect to how these properties affect their attachment (6,9). The contrasting results in the literature may be due to the number of strains and species included.…”

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confidence: 83%

“…The first step in the contamination of a surface is the attachment of cells to the substrate (10). E. coli O157:H7 has been shown to attach to a variety of substrates, including stainless steel (SS) (16,18), glass and Teflon (9), fresh produce (2), beef muscle and adipose tissue (15), and cultured intestinal cell lines (19).…”

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confidence: 99%

CsgA Production by Escherichia coli O157:H7 Alters Attachment to Abiotic Surfaces in Some Growth Environments

Goulter-Thorsen

Taran

Gentle

et al. 2011

The role of curli expression in attachment of Escherichia coli O157:H7 to glass, Teflon, and stainless steel (SS) was investigated through the creation of csgA knockout mutants in two isolates of E. coli O157:H7. Attachment assays using epifluorescence microscopy and measurements of the force of adhesion of bacterial cells to the substrates using atomic force microscopy (AFM) force mapping were used to determine differences in attachment between wild-type (wt) and csgA-negative (⌬csgA) strains following growth in four different media. The hydrophobicity of the cells was determined using contact angle measurements (CAM) and bacterial adhesion to hydrocarbons (BATH). The attachment assay results indicated that ⌬csgA strains attached to glass, Teflon, and SS surfaces in significantly different numbers than their wt counterparts in a growth medium-dependent fashion (P < 0.05). However, no clear correlation was seen between attachment numbers, surface type, or growth medium. No correlation was seen between BATH and CAM results (R 2 < 0.70). Hydrophobicity differed between the wt and ⌬csgA in some cases in a growth medium-and method-dependent fashion (P < 0.05). AFM force mapping revealed no significant difference in the forces of adhesion to glass and SS surfaces between wt and ⌬csgA strains (P > 0.05) but a significantly greater force of adhesion to Teflon for one of the two wt strains than for its ⌬csgA counterpart (P < 0.05). This study shows that CsgA production by E. coli O157:H7 may alter attachment behavior in some environments; however, further investigation is required in order to determine the exact relationship between CsgA production and attachment to abiotic surfaces.

“…Attachment data from this study were compared with previously reported physiochemical and attachment data from the same isolates. No correlation was observed between the results of this study and hydrophobicity results obtained using hydrophobic interaction chromatography (R 2 ϭ 0.0004 to 0.0089), contact angle measurement (R 2 ϭ 0.0158 to 0.0347), bacterial attachment to hydrocarbons (for hexadecane, R 2 ϭ 0.0055 to 0.0839; for xylene, R 2 ϭ 0.0021 to 0.0769), or previously described stainless steel attachment results (R 2 ϭ 0.000006 to 0.1630) (3,18,19;Chia et al,submitted). It should be noted in these previous studies no direct correlation was observed between attachment of E. coli to stainless steel and cell surface hydrophobicity (18).…”

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confidence: 76%

“…No correlation was observed between the results of this study and hydrophobicity results obtained using hydrophobic interaction chromatography (R 2 ϭ 0.0004 to 0.0089), contact angle measurement (R 2 ϭ 0.0158 to 0.0347), bacterial attachment to hydrocarbons (for hexadecane, R 2 ϭ 0.0055 to 0.0839; for xylene, R 2 ϭ 0.0021 to 0.0769), or previously described stainless steel attachment results (R 2 ϭ 0.000006 to 0.1630) (3,18,19;Chia et al,submitted). It should be noted in these previous studies no direct correlation was observed between attachment of E. coli to stainless steel and cell surface hydrophobicity (18). While at a strain level, hydrophobicity did not appear to influence bacterial adhesion capacity, when analyzed at a species level, the mean values for hydrophobicity measurements (using bacterial attachment to hydrocarbons for hexadecane and hydrophobic interaction chromatograpy) showed E. coli to be significantly more hydrophobic than Salmonella (P Յ 0.05), which may be linked to the greater attachment of the former species to the cell lines.…”

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confidence: 76%

Comparative Analysis of Attachment of Shiga-Toxigenic Escherichia coli and Salmonella Strains to Cultured HT-29 and Caco-2 Cell Lines

Mellor

Goulter

Chia

et al. 2009

Self Cite

The ability of Escherichia coli and Salmonella isolates to attach to Caco-2 and HT-29 cell monolayers was measured. All isolates displayed a greater ability to attach to Caco-2 cells than HT-29 cells, and overall E. coli isolates attached better to both cell lines than Salmonella isolates. Bacteria that were considered to be pathogenic displayed no greater ability to attach to cell lines than those that were not considered to be pathogenic. Additionally, no correlation was found between cell line attachment and previously determined hydrophobicity results.Cultured intestinal cell lines are often used in attachment assays as indicators of the pathogenic potential of bacteria (9, 15). The ability of bacteria to attach to the intestinal epithelium may help explain the differences in pathogenicity among strains (4). It has also been suggested that bacterial physicochemical properties, such as cellular surface charge and hydrophobicity, can influence bacterial attachment to surfaces, including human intestinal cell lines (7,12,20).The usefulness of attachment assays for food-borne bacterial pathogens and the influence of physicochemical properties on attachment are not always clear from the literature. Previous studies investigating the attachment of bacteria to cell lines have used either a small number of isolates (15) or several strains from a number of different species (9). This study was undertaken to investigate how a large number of closely related bacterial isolates with different physicochemical properties, encompassing those commonly associated with human disease (e.g., Salmonella enterica serovar Typhimurium, S. enterica serovar Virchow, S. enterica serovar Infantis, and Shigatoxigenic Escherichia coli [STEC] serotype O157) and those that are not (e.g., S. enterica serovar Sofia, and non-STEC) differ in the degree of attachment to intestinal cell lines.Twenty strains of E. coli previously used in other studies (18) investigating attachment to stainless steel (Table 1), along with 25 Salmonella strains previously used in other studies (T. W. R. Chia, R. M. Goulter, T. McMeekin, G. A. Dykes, and N. Fegan, submitted for publication) investigating attachment to stainless steel, glass, nitrile butyl-rubber, polyurethane, and Teflon (Table 1), were selected for the cell attachment assay. Isolates were cultured on tryptic yeast soya glucose agar (TYSG) from Protect beads (Technical Service Consultants, Lancashire, United Kingdom) and stored at 4°C. Cultures were grown in 10 ml tryptic soya broth (TSB; Oxoid, Basingstoke, United Kingdom) and incubated at 37°C under aerobic conditions for 18 Ϯ 2 h. A 1-ml aliquot of each overnight culture was added to 9 ml of phosphate-buffered saline (PBS; 2.67 mM KCl, 137 mM NaCl, 8.1 mM Na 2 HPO 4 , 0.74 mM KH 2 PO 4 , pH 7.4) centrifuged at 4,500 ϫ g for 10 min, and washed once with 10 ml PBS. In order to achieve a bacterial suspension of ϳ1.5 ϫ 10 8 cells/ml, the pellet was resuspended in Dulbecco's modified minimal essential medium (DMEM; 1ϫ high glucose) containing 25 mM D-...