A comparison of a monoclonal antibody-based sandwich ELISA and immunomagnetic bead selective enrichment for the detection of Escherichia coli O157 from bovine faeces

Abstract

Aims: To compare a recently developed monoclonal antibody (MAb) based sandwich ELISA (sELISA) with an immunomagnetic separation (IMS) method for the detection of Escherichia coli O157 in bovine faeces. Methods and Results: Faecal samples from 345 cattle were obtained from eight farms in Northern Ireland, in which human disease due to E. coli O157 had occurred. Both assays detected E. coli O157 on ®ve of the farms and the phage-type of the majority of the bovine strains were the same as the corresponding human isolates. Similar numbers of the organism were detected by the two methods, 59 by the sELISA and 53 by the IMS procedure, 39 of the positive samples being common to both. Twenty samples were sELISA positive/IMS negative. Conclusions: If the IMS is regarded as the gold standard, then the sELISA is less sensitive and less speci®c, but under the conditions used sELISA positive results were obtained from all positive farms, and the sELISA gave a presumptive positive a day earlier than the IMS method. Signi®cance and Impact of the Study: The sELISA has the potential to be used as a rapid method for screening large numbers of samples for E. coli O157, but further work is required to determine its speci®city.

Development of a monoclonal sandwich ELISA for the detection of animal and human Escherichia coli O157 strains

“…This potential has been examined, in comparison to the widely used immunomagnetic bead assay (Chapman et al . 1997a), for bovine faecal samples and has provided additional evidence of its usefulness (Kerr et al . in press).…”

Antibody-Based Sensors: Principles, Problems and Potential for Detection of Pathogens and Associated Toxins

“…The versatility of this technique is further illustrated by the ability to detect pathogen-antibody complexes with beads coated with a cognate secondary antibody, an indirect assay format demonstrated by Torensma and co-workers [44] for the detection of L. monocytogenes cells bound to a murine monoclonal antibody produced from the immunisation with whole bacterial cells. IMS has also been applied for the detection of these cells in cheese [45], S. typhimurium in bovine faecal matter [46] and E. coli O157:H7 in beef carcasses [20,47] and bovine faeces [48]. …”

The prevalence and concentration of Escherichia coli O157 in faeces of cattle from different production systems at slaughter

“…Immunomagnetic separation (IMS) and immunocapture (IC) techniques are currently the preferred methods available for the isolation and detection of E. coli O157 (Cubbon et al. 1996; de Boer and Heuvelink 1998; Kerr et al. 2001), as the limit of detection is up to 100‐fold greater than direct culture methods (Chapman et al.…”