Verocytotoxin-producing E. coli O157 are an important cause of diarrhoea, haemorrhagic colitis and haemolytic uraemic syndrome3,4. The pathogenicity of this organism is due to the expression of verocytotoxin (VT1 and/or VT2)5-7. Enteritis due to other serotypes is not unusual but in contrast to the majority of isolates, most E. coli O157:H7 do not ferment sorbitol and this has been used as a differential feature for laboratory identification. Testing suspect colonies with Wellcolex* E. coli O157 helps determine whether the isolate belongs to the O157 serogroup.
The Wellcolex* E. coli O157 Rapid Latex Test is categorised as highly complex under the Clinical Laboratory Improvement Act (CLIA88 : Test System Code 40262; Analyte Code 1604).
- Ready-to-use: Color coded latex and control reagents
- Rapid: Results within 30 seconds.
- Easy-to-interpret: Visible agglutination
- Less sample required
The Wellcolex* E. coli O157 Test Reagent consists of a buffered suspension of red polystyrene latex particles coated with rabbit IgG antibodies specific for E. coli O157 and 0.05% Bronidox® as preservative. When a drop of the reagent is mixed on a card with a suspension of E. coli O157 organisms, rapid agglutination occurs through the interaction of specific IgG and O157 lipopolysaccharide antigen.
Some faecal coliforms can cause non-specific aggregation of latex particles, particularly when grown on sugar containing media such as MacConkey. Therefore a control latex is provided to assist with the identification of non-specific reactions. The control latex consists of a buffered suspension of red polystyrene latex particles coated with non-immune rabbit IgG and 0.05% Bronidox® as preservative.
The kit is also supplied with Positive and Negative controls. The positive control contains a dilute suspension of heat killed E. coli O157 antigens and 0.05% Bronidox® preservative. The negative control contains a dilute suspension of heat killed E. coli O106 antigens and 0.05% Bronidox® preservative.
Not all products are available for sale in all territories. Please inquire.
Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.
- March, S.B. and Ratnam, S. (1986). Sorbitol-MacConkey medium for detection of Escherichia coli O157:H7 associated with hemorrhagic colitis. Journal of Clinical Microbiology, 23:869-872.
- Gray, L.D. (1995). Manual of Clinical Microbiology, 6th Ed., edited by Murray, P.R., Baron, E.J., Pfaller, M.A., Tenover, F.C and Yolken, R.H. American Society for Microbiology, Washington, D.C. Pages 450-456.
- Tarr, P.I. (1995). Escherichia coli O157:H7: Clinical, diagnostic and epidemiological aspects of human infection. Clinical Infectious Diseases, 20:1?
- Wells, J.G., Davis, B.R., et al. (1983). Laboratory investigation of hemorrhagic colitis outbreaks associated with rare Escherichia coli serotype. Journal of Clinical Microbiology, 18:512-520.
- Ratnam, S., March, S.B., et al. (1988). Characterization of Escherichia coli serotype O157:H7. Journal of Clinical Microbiology, 26:2006-2012.
- Willshaw, G.A., Scotland, S.M., et al. (1992). Properties of Verocytotoxin-producing Escherichia coli of human origin of O serogroups other than O157. Journal of Infectious Diseases, 166:797?
- Thielman, N.M. (1994). Enteric Escherichia coli infections. Current Opinion in Infectious Diseases, 7:582-591.
