Assurance Escherichia coli 0157:H7: A Comparative Validation Study

Feldsine, Philip T; Forgey, Robin L; Falbo-Nelson, Maria T; Brunelle, Sharon L

doi:10.1093/jaoac/80.1.37

Cited by 3 publications

(3 citation statements)

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“…Other commercial test systems include the Ampcor™ E. coli 0157:H7 Kit (Ridascreen-Biopharm GmbH, Darmstadt, Germany), Micro-Screen™ for E. coli 0157:H7 (Neogen, Lansing, MI, USA), VIp™ Test for EHEC (BioControl Systems, Bothell, Washington, USA) (Feldsine et al 1997b), Tecra™ E. coli 0157 visual immunoassay (Tecra) (Flint and Hartley 1995), Vidas™ E. coli 0157 Assay (Biolvlerieux, St Louis, MO, USA) and Assurance EHEC™ (BioControl Systems) (Feldsine et al 1997a). These commercial test kits reduce analysis time and give presumptive results after one day, compared with cultural procedures that require two days.…”

Section: Enzyme-linked Immunoassaysmentioning

confidence: 99%

Methods for the detection and isolation of Shiga toxin-producingEscherichia coli

Boer

Heuvelink

2000

Journal of Applied Microbiology

117

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SUMMARY Shiga toxin‐producing Escherichia coli (STEC) are an important cause of haemorrhagic colitis and the diarrhoea‐associated form of the haemolytic uraemic syndrome. Of the numerous serotypes of E. coli that have been shown to produce Shiga toxin (Stx), E. coli O157:H7 and E. coli O157:NM (non‐motile) are most frequently implicated in human disease. Early recognition of STEC infections is critical for effective treatment of patients. Furthermore, rapid microbiological diagnosis of individual patients enables the prompt notification of outbreaks and implementation of control measures to prevent more cases. Most human infections caused by STEC have been acquired by the consumption of contaminated foods, especially those of bovine origin such as undercooked ground beef and unpasteurized cows' milk, and by person‐to‐person contacts. To identify the reservoirs of STEC and the routes of transmission to man, sensitive methods are needed as these pathogens may only be present in food, environmental and faecal samples in small numbers. In addition, sensitive and rapid detection methods are necessary for the food industry to ensure a safe supply of foods. Sensitive methods are also needed for surveillance programmes in risk assessment studies, and for studies on survival and growth of STEC strains. Cultural methods for the enrichment, isolation and confirmation of O157 STEC are still evolving. Several selective enrichment media have been described, of which modified tryptone soy broth with novobiocin and modified E. coli broth with novobiocin, seem to be the most appropriate. These media are minimally‐selective broths that give a somewhat limited differential specificity favouring isolation of O157 STEC, as opposed to other Gram‐negative bacteria, in the sample. An incubation temperature of 41–42°C further enhances selectivity. The occurrence of heat‐, freeze‐, acid‐ or salt‐stressed STEC in foods means that it is important to be able to detect cells that are in a stressed state, as STEC generally have a very low infectious dose, and injured cells mostly retain their pathogenic properties. For the isolation of stressed O157 STEC, pre‐enrichment in a non‐selective broth is necessary. The most widely used plating medium for the isolation of typical sorbitol‐non‐fermenting strains of STEC of serogroup O157 is sorbitol MacConkey agar with cefixime and tellurite (CT‐SMAC). As some STEC strains are sensitive for tellurite and/or are sorbitol‐fermenting, the use of a second isolation medium, such as one of the newer chromogenic media, is recommended. Immunomagnetic separation (IMS) following selective enrichment, and subsequent spread‐plating of the concentrated target cells onto CT‐SMAC agar, appears to be the most sensitive and cost‐effective method for the isolation of E. coli O157 from raw foods. IMS increases sensitivity by concentrating E. coli O157 relative to background microflora, which may overgrow or mimic O157 STEC cells on selective agars. While cultural isolation of O157 STEC from foods and faeces is time‐consu...

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Section: Enzyme-linked Immunoassaysmentioning

confidence: 99%

Methods for the detection and isolation of Shiga toxin-producingEscherichia coli

Boer

Heuvelink

2000

Journal of Applied Microbiology

117

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“…Recent studies in this field employed methods such as ELISA, 6,7 enrichment culture 8 and visual immunoprecipitate assay. 9 These require 3-5 d for completion.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies in this field employed methods such as ELISA, 6,7 enrichment culture 8 and visual immunoprecipitate assay. 9 These require 3-5 d for completion. The most rapid assays described were based on a resuscitation-selection-kit system 10 and a piezoelectric (PZ) biosensor.…”

Section: Introductionmentioning

confidence: 99%

Increasing the sensitivity of Listeria monocytogenes assays: evaluation using ELISA and amperometric detection

Crowley¹,

O’Sullivan²,

Guilbault³

1999

Analyst

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An immunosensor for the detection of Listeria monocytogenes was developed. ELISA and amperometric studies were run in parallel to develop a more sensitive and rapid assay for the bacterium. Conditions for the immunosensor were primarily characterised using ELISA. A direct sandwich assay was employed and the affinities of two polyclonal (goat and rabbit) and one monoclonal (mouse) anti-L. monocytogenes antibodies were compared using this format. Owing to low sensitivity being obtained with all antibodies, biotin-avidin amplification and an indirect sandwich assay were employed. The system was then transferred to screen-printed electrodes (SPEs), the primary antibody being immobilised by cross-linking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, and the mode of detection being amperometric. Various parameters (limit of detection, working range, incubation time, cross-reactivity) of the systems were characterised. The effect of direct incubation in milk is also discussed. The final immunosensor had a working range of 1 x 10(6)-1 x 10(3) cells ml-1 and a detection limit of 9 x 10(2) cells ml-1. The assay took about 3.5 h to complete.

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Enumeration of coliforms and Escherichia coli in frozen black tiger shrimp Penaeus monodon by conventional and rapid methods

Suwansonthichai

Rengpipat

2003

International Journal of Food Microbiology

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Assurance Escherichia coli 0157:H7: A Comparative Validation Study

Cited by 3 publications

References 0 publications

Methods for the detection and isolation of Shiga toxin-producingEscherichia coli

Methods for the detection and isolation of Shiga toxin-producingEscherichia coli

Increasing the sensitivity of Listeria monocytogenes assays: evaluation using ELISA and amperometric detection

Enumeration of coliforms and Escherichia coli in frozen black tiger shrimp Penaeus monodon by conventional and rapid methods

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