The emergence of new genetic lineage, ST-3753, of Neisseria meningitidis serogroup B in Auvergne-Rhône-Alpes region, France 2021-2022
Résumé
Introduction
After two years of decreased incidence of invasive meningococcal disease (IMD), cases seem to rebound with an increase in the incidence of IMD due to group B (IMDB) at national and local levels in France with a recent cluster of cases in the region Auvergne-Rhône-Alpes, France.
Aims
We aimed to characterize this local increase in incidence to inform the decision-making process in terms of cluster management.
Materials and Methods. Surveillance epidemiological and bacteriological data in France were used in combination with whole genome sequencing (WGS) to detect emerging meningococcal isolates causing IMD. Epidemiological characteristics of cases, genomic analysis of the isolates, and their coverage by vaccines were analyzed.
Results
During the 52 weeks from 15 august 2021 to 14 August 2022, we detected 28 IMDB cases in the Auvergne-Rhône-Alpes region. A local increase of IMDB isolates was detected with an incidence of 0.35 cases per 100,000 inhabitants versus 0.15 at the national level. Among these 28 isolates, 12 were identical and associated with a shift to 15-24 years of age. All 12 isolates belonged to a new sequence type ST-3753 of the clonal complex ST-41/44 (CC41/44). WGS clustered these isolates together and were separated from other isolates of CC41/44. These isolates were predicted to be covered by vaccines against group B meningococci. Epidemiological investigations identified two geographical clusters around Chambery (cluster 1) and Eastern Lyon (cluster 2). Vaccination was therefore recommended in these two areas targeting individuals 16-24 years old.
Conclusion
Combining real-time WGS with epidemiological surveillance offers a rapid and reliable tool to optimize the implementation of outbreak control measures.
Domaines
Sciences du Vivant [q-bio]
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