Identification of Listeria species by microarray-based assay

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Accurate identification of Listeria species is crucial for food safety and public health.
• Existing methods for Listeria detection can be time-consuming and lack specificity.
• Virulence factor genes offer potential targets for species-specific identification.

Purpose of the Study:

• To develop and validate a rapid, reliable microarray-based assay for discriminating six Listeria species.
• To utilize multiplex PCR amplification of bacterial virulence factor genes for identification.
• To assess the utility of this method for general bacterial pathogen characterization.

Main Methods:

• One-tube multiplex PCR amplification of six target virulence factor genes (iap, hly, inlB, plcA, plcB, clpE).
• Synthesis of fluorescently labeled single-stranded DNA.
• Hybridization to species-specific oligonucleotide probes immobilized on a glass microarray surface.

Main Results:

• The microarray assay unambiguously identified all six Listeria species (L. monocytogenes, L. ivanovii, L. innocua, L. welshimeri, L. seeligeri, L. grayi) based on iap gene sequence differences.
• The hly gene was used for detection and genotyping of L. monocytogenes, L. ivanovii, and some L. seeligeri isolates.
• Complete agreement was observed between genotyping based on hly and iap gene sequences. All L. monocytogenes isolates were positive for species-specific virulence genes (inlB, plcA, plcB, clpE).

Conclusions:

• The developed microarray technique is a simple, rapid, and robust genotyping method for Listeria species.
• This approach demonstrates potential as a valuable tool for the identification and characterization of bacterial pathogens.
• The assay provides reliable discrimination among key Listeria species, aiding in food safety and clinical diagnostics.