Application of an immunomagnetic assay system for detection of virulent bacteria in biological samples

Virulent pathogenic bacteria could pose a serious health threat in contaminated food and water resources. Traditional bacterial culture methods or enzyme linked immunosorbent assay (ELISA) for identification of the bacteria are time consuming and labor intensive. Some new technologies are very sensitive but analysis time can be lengthy. For example, the polymerase chain reaction (PCR) can be used to amplify small quantities of genetic material to determine the presence of bacteria. This is a sensitive method that requires pure samples and considerable laboratory time. Alternative methods should be quicker and retain sensitivity. The magnetic separation technique appears promising for rapid bacterial isolation from the media prior to the detection. In this work, immunomagnetic assay system (IMAS) has been coupled to an electrochemiluminescent (ECL) technology for rapid and sensitive bacterial detection of biological samples within an hour. The sensitivity of the IMAS-ECL for Bacillus anthrax spores (sterne), Escherichia coli O157:H7 and Salmonella typhimurium detection is about 1000 cells/mL, in biological samples. In addition, IMAS can also be coupled to a now cytometer or any analytical instruments for target agent monitoring. Results of this study strongly suggest that IMAS methodology is useful for rapid and sensitive detection.