Rapid microarray-based DNA genoserotyping of Escherichia coli

Area of Science:

• Microbiology
• Genetics
• Molecular Diagnostics

Background:

• Classical serotyping of Escherichia coli relies on antibody-based agglutination, which is time-consuming and labor-intensive.
• Accurate identification of O and H antigen groups is crucial for epidemiological surveillance and understanding E. coli pathogenicity.

Purpose of the Study:

• To present an improved oligonucleotide-based DNA microarray for enhanced genoserotyping of Escherichia coli.
• To expand the microarray's capacity to cover additional O antigen groups and transfer it to a high-throughput platform.

Main Methods:

• Development of primers and probes for 70 additional O antigen groups.
• Transfer of the microarray to the ArrayStrip platform for high-throughput, automated analysis in a 96-well format.
• Validation using defined reference strains and a diverse set of 180 human clinical isolates and 53 animal E. coli isolates.

Main Results:

• The enhanced microarray can determine 94 O antigen groups and 47 H antigens from a single colony within hours.
• High concordance was observed between the DNA-based genoserotyping results and conventional antibody-based serotyping.
• The ArrayStrip format facilitates fully automated microarray analysis.

Conclusions:

• The improved oligonucleotide array offers a user-friendly, efficient, and standardized diagnostic tool for E. coli genoserotyping.
• This method is more efficient than classical agglutination and suitable for routine laboratory application.
• The assay is easily expandable and can be standardized across different laboratories.