An amplification-free hybridization-based DNA assay to detect Streptococcus pneumoniae utilizing the up-converting phosphor technology

Objectives: Development of a generally applicable sensitive hybridization-based assay devoid of any target amplification for the detection and identification of (pathogenic) bacterial and viral species. Design and methods: Using a sandwich hybridization format, the presence of a species-specific nucleic acid sequence is detected by means of Lateral Flow (LF) and Up-converting Phosphor Technology (UPT, a luminescent tracer). As a model, detection of the pathogen Streptococcus pneumoniae was investigated using a probe against the single-copy lytA gene. Results: Detection of S. pneumoniae (in particular a 1200 p lytA sequences) required less than I ng of genomic DNA (approximate size 2.2 Mb). Hybridization and detection were performed in a complex background containing 10 mug fish sperm DNA. Conclusions: The results indicate the possibility to detect nucleic acid targets in nonamplified DNA samples using easy, inexpensive, amplification-free hybridization-based assays and the ultra sensitive UPT reporters. Employment of UPT allows to by-pass target amplification and therefore brings genetic-based testing a step closer to the point-of-care environment. Detection of S. pneumoniae with only I ng of DNA indicates a potential for applications in the field of infectious diseases. (C) 2003 The Canadian Society of Clinical Chemists. All rights reserved.