HE EMERGENCE OF A NEW GENETIC LINEAGE (ST-9316) OF NEISSERIA MENINGITIDIS SGROUP W IN NORTH FRANCE
Résumé
Materials and Methods
All invasive isolates that are received at the National Reference Centre are analyzed by whole genome sequencing (WGS,
NextSeq 500, Illumina). The isolates are uploaded regularly to the PUBMLST and periodically analyzed using genome
comparator tools. The SplitsTree4 (version 4.13.1) is used to visualise the resulting distance matrices as Neighbor-net
networks.
Results
Serogroup W isolates are increasing in France since 2013 and most of the isolates belonged to the clonal complex ST-11
and were derivatives of the South American UK strain. However, between 2013 and 2018, 24 cases of IMD due to isolates
belonging to an unusual sequence type, the ST-9316, were identified in France mainly in the north part of the country. The
majority of cases belonged to group W but few were of groups B and C. These isolates do not belong to any already defined
clonal complex (CC). The cases were distributed as follows: 1 case in 2013, 2 cases in 2015, 6 cases in 2016, 9 cases in 2017
and 6 in 2018. The index case of this ST-9316 cluster was identified in December 2013 in the Hauts-de-France from a 29 years
old woman. Cases were distributed in all groups of age.
Coregenome MLST clustered all the isolates belonging to the ST-9316 together and were distantly separated from the other
isolates that differed by more than 1300 alleles. However, those isolates were closer to the isolates of the CC865. The W/
ST-9316 isolates shared several identical allelic profiles that were different from those of lineages of CC11 isolates. Most of
the corresponding genes encode metabolic enzymes. However, few other genes involved in interactions with host cells such
as genes encoding FetA, PorA, factor H binding protein (Fhbp). Interestingly, all the W/ST-9316, unlike the W/CC11 isolates,
lacked the hmbR gene encoding the haemoglobin receptor that is involved in the acquisition of iron from haemoglobin.
Conclusion
Changing meningococcal epidemiology may occur rapidly and locally. Surveillance requires extensive and powerful
approaches such as WGS to rapidly adapt preventive strategies.
Domaines
Sciences du Vivant [q-bio]
Origine : Fichiers produits par l'(les) auteur(s)