Automated methods for multiplexed pathogen detection

• Published in: Journal of microbiological methods Vol. 62; no. 3; pp. 303 - 316
• Main Authors: Straub, Timothy M., Dockendorff, Brian P., Quiñonez-Díaz, Maria D., Valdez, Catherine O., Shutthanandan, Janani I., Tarasevich, Barbara J., Grate, Jay W., Bruckner-Lea, Cynthia J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Shannon Elsevier B.V 01.09.2005; Elsevier Science
• Subjects: Analytical separations; Automated methods; Automation - methods; Bacteriological methods and techniques used in bacteriology; Bacteriology; Base Sequence; Biodetection; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; DNA, Bacterial - genetics; Environmental Microbiology; Equipment Design; Escherichia coli; Escherichia coli O157 - genetics; Escherichia coli O157 - isolation & purification; Fundamental and applied biological sciences. Psychology; Immunomagnetic Separation; Isolation and description; Microarrays; Microbiological Techniques - instrumentation; Microbiology; Mission oriented research; Oligonucleotide Array Sequence Analysis; Pathogens; Polymerase Chain Reaction - methods; RNA, Bacterial - genetics; RNA, Bacterial - isolation & purification; Salmonella; Salmonella - genetics; Salmonella - isolation & purification; Shigella; Shigella - genetics; Shigella - isolation & purification; Pathogens; Automated methods; Biodetection; Analytical separations; Microarrays; Salmonella; Automaton; Escherichia coli; Method; Northern blotting; Polymerase chain reaction; Immunocapture; Pathogenic; Bacteria; Detection; Shigella; Enterobacteriaceae
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/j.mimet.2005.04.012

Detection of pathogenic microorganisms in environmental samples is a difficult process. Concentration of the organisms of interest also co-concentrates inhibitors of many end-point detection methods, notably, nucleic acid methods. In addition, sensitive, highly multiplexed pathogen detection continues to be problematic. The primary function of the BEADS (Biodetection Enabling Analyte Delivery System) platform is the automated concentration and purification of target analytes from interfering substances, often present in these samples, via a renewable surface column. In one version of BEADS, automated immunomagnetic separation (IMS) is used to separate cells from their samples. Captured cells are transferred to a flow-through thermal cycler where PCR, using labeled primers, is performed. PCR products are then detected by hybridization to a DNA suspension array. In another version of BEADS, cell lysis is performed, and community RNA is purified and directly labeled. Multiplexed detection is accomplished by direct hybridization of the RNA to a planar microarray. The integrated IMS/PCR version of BEADS can successfully purify and amplify 10 E. coli O157:H7 cells from river water samples. Multiplexed PCR assays for the simultaneous detection of E. coli O157:H7, Salmonella, and Shigella on bead suspension arrays was demonstrated for the detection of as few as 100 cells for each organism. Results for the RNA version of BEADS are also showing promising results. Automation yields highly purified RNA, suitable for multiplexed detection on microarrays, with microarray detection specificity equivalent to PCR. Both versions of the BEADS platform show great promise for automated pathogen detection from environmental samples. Highly multiplexed pathogen detection using PCR continues to be problematic, but may be required for trace detection in large volume samples. The RNA approach solves the issues of highly multiplexed PCR and provides “live vs. dead” capabilities. However, sensitivity of the method will need to be improved for RNA analysis to replace PCR.