Rapid Oligonucleotide Suspension Array-Based Multiplex Detection of Bacterial Pathogens

A gene-specific microsphere suspension array coupled with 15-plex polymerase chain reaction (PCR) was developed to screen bacterial samples rapidly for 10 strains of bacteria: Shigella spp. (S. flexneri, S. dysenteriae, and S. sonnei), Staphylococcus aureus, Vibrio cholerae (serology O1 and O139), Legionella pneumophila, and Clostridium botulinum (types A, B, and E). Fifteen sets of highly validated primers were chosen to amplify target genes simultaneously. Corresponding oligonucleotide probes directly conjugated with microsphere sets were used to specifically identify PCR amplicons. Sensitivity tests revealed that the array coupled with single PCR was able to detect purified genomic DNA at concentrations as low as 10 copies/L, while the multiplex detection limit was 10-10(4) copies/L. The assay was validated using water samples artificially spiked with S. aureus and S. dysenteriae, as well as water specimens from swimming pools previously identified to contain S. aureus.