Enzyme-linked immunomagnetic chemiluminescence incorporating anti-H7 and anti-O157 antibodies for the detection of Escherichia coli O157:H7

The pathogenic bacteria Escherichia coli O157:H7 has been associated with numerous cases of foodborne illnesses. Many rapid methods have been developed for the screening of this pathogen in foods in order to circumvent timely plate culture techniques. However, many of these methods are presumptive and do not claim to confirm the presence of E. coli O157:H7. We developed a rapid method (termed enzyme-linked immunomagnetic chemiluminescence [ELIMCL]) that employed a relatively affordable and portable luminometer with a superparamagnetic microparticle-based enzyme-linked sandwich immunoassay. A key feature of this assay is that it combines the highly selective synergism of both anti-O157 and anti-H7 antibodies in the sandwich immunoassay format, thus allowing for potential confirmation of the pathogen. This work presented the development of ELIMCL that incorporated a one-step sandwich immunoassay that was demonstrated to have a limit of detection of approximately 1 e5-1 e6 live cells/mL of E. coli O157:H7 in pristine-buffered saline in approximately 1 h or at least 50 cells/mL of E. coli O157:H7 inoculated into ground beef and culture enriched for 5.5 h.