LegioType AS-1

(item number: 240008874)

  • Legionella outbreaks require rapid typing. Since serotypes and genotypes as defined by sequence based typing (SBT) do not correlate, situations might arise in which both approaches need to be performed in parallel which is cumbersome and expensive. Aim of the study was to design and to test an assay based on DNA microarray hybridisation that facilitates a rapid assignment of Legionella isolates to strains.

  • Twenty-one genes and five intergenic regions were used for probe and primer design resulting in an array with ninety-seven probes. Amplification and internal labelling with biotin-dUTP is performed using a linear multiplex primer elongation. Amplicons are hybridised to the probes on the array, and, after washing steps, visualised by addition of streptavidin-horseraddish-peroxidase and a locally precipitating dye. Arrays are scanned, and spot formations were analysed using a dedicated reader.

  • Approximately 700 isolates were screened yet using the array, serotyped and genotyped by SBT. Isolates cluster into 111 "strains“ based on identical array hybridisations and antibody reactivity as well as on sequence type/clonal complex affiliations. These data were used to construct a database and a software for strain identification based on pattern recognition and comparison to stored reference profiles. The current software was found to assign isolates correctly in about 90% of cases. Discrepant identifications could partially attributed to technical reasons such as user errors, but also to the presence of several similar strains within the sequence type 1/serogroup 1 complex that deserve further study and re-definition.

  • The technology described has the potential to be developed to a frontline tool for quick Legionella typing in outbreak situations because it forestalls results of genotyping, i.e., SBT, and phenotypic, i.e., serotyping, approaches allowing assignment to phylogenetic lineages and serological groups within a single experiment. The underlying database will be expanded with future use.

Array-on-demand

Alere Technologies provides customized manufacturing of microarrays mounted in ArrayTubes and/or ArrayStrips. You decide which markers/genes you focus on.

Genotyping Service

Please send either a clonal culture (e.g., suitable agar plate, stab culture or swab) or a high quality DNA preparation into our lab. We do the genotyping and you get a result file in electronic form.

List of referring online publications.


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