Multi Locus Sequence Typing (MLST)

Test description

Description:

• Extraction of genomic DNA, sequencing by ISO accredited methods (such as wet — and dry lab). From this NGS, the identification of the MLST (Multilocus Sequence Type) is performed according to Ragon’s method: The ‘sequence type’ (ST) and ‘clonal complex’ (CC) are determined from 7 housekeeping genes, with the sequences checked on-line against a database (Institut Pasteur, Paris).
• cgMLST (core genome MLST) : The sequence of a set of ‘core genome’ genes is obtained via ‘Whole genome sequencing’ and compared with an on-line database (Institut Pasteur, Paris).

Result :

The obtained profile allows to compare the strains with other strains and investigate the source of contamination.

Purpose of the test

Molecular subtyping of Listeria monocytogenes by NGS-based analyses. 

Criteria for performing this test in the context of reference activities

Molecular subtyping of all Listeria monocytogenes strains (confirmed by the NRC) isolated from patients showing symptoms of listeriosis (analysis performed as part of NRC Listeria surveillance).

Instructions for samples

• Type: Isolated strains of Listeria on a transport medium or other solid medium. Exceptionally, a DNA extract of the sample may also be sent. 
• Minimum quantity: Not applicable.

Instructions for transport

The strain is sent at room temperature and must be packed in a double protective container for safety reasons. This container must be hermetically sealed.

Unacceptable applications

Not applicable.

Turnaround time (and frequency of analysis)

• Turnaround time: 20 working days
• Analysis days: Any weekday ( excluding: public holidays, extended weekends and the period between Christmas and New Year).

Reporting of test results

This analysis is carried out as part of surveillance. If the applicant requires a report of this analysis, it is best to contact the NRC by telephone or electronically . The analysis report will then be sent in the manner desired by the applicant.