Pro-Lab E. coli O157 Antiserum is for use in the slide agglutination test for the presumptive identification of Escherichia coli serotype O157 antigen on laboratory culture media.
Escherichia coli serotype O157:H7 is a verotoxin producing (VT-producing) pathogen. This serotype has been reported as an etiological agent in sporadic and outbreak cases of haemorrhagic colitis. It is also associated with haemolytic uraemic syndrome. Certain E. coli serotypes other than O157:H7 also produce verotoxin. However, the diarrhoea caused by these other serotypes is not usually bloody. Additionally, E. coli serotype O157:H7 does not ferment sorbitol whereas the majority of other serotypes do ferment sorbitol. Therefore, if Sorbitol-MacConkey agar medium is used as a primary screen, the colonies of E. coli serotype O157:H7 appear colourless (non-sorbitol fermenting colonies - NSFC) while colonies of other serotypes appear characteristically pink (sorbitol fermenting colonies - SFC).The work of Kauffmann12, Edward and Ewing13, Ewing14 and Orskov15 contributed to the development of a system for serological typing of E. coli cultures and resulted in an antigenic classification scheme which can be used to identify the serotypes of Escherichia coli which are associated with bacteriuria or diarrheal disease.
The principle of the test involves mixing the suspected organisms with the antiserum containing E. coli O157 antibodies. The bacteria will agglutinate (clump) in the presence of homologous antiserum.
Pro-Lab E. coli O157 Antiserum is prepared using delipidized, whole absorbed rabbit serum containing antibodies to E. coli serotype O157.
The antiserum is to be used for the presumptive identification or confirmation of cultures which have been previously characterized biochemically
Pro-Lab E. coli O157 Antiserum is supplied in a dropper bottle containing 3.0 ml of ready-to-use diluted antiserum with 0.01% thimerosal as preservative.