Detailed molecular characterization of Neisseria meningitidis isolates by whole genome sequencing (WGS), Czech Republic, 2010-2019.

Abstract

Aim: Presentation of the first results of the analysis of Neisseria meningitidis isolates from invasive meningococcal disease and from clinically and/or epidemiologically linked cases from 2010-2019. Whole genome sequencing (WGS) was used for the study.

Material and methods: The study set included 59 isolates of N. meningitidis from 2010-2019. Serogrouping was done by conventional serological methods and confirmed by RT-PCR. WGS was used for detailed molecular characterization, covering not only basic genes but also ribosomal and capsular genes, antibiotic resistance gene penA, and outer membrane protein gene porA.

Results: WGS analysis of N. meningitidis isolates resulted in a detailed molecular characterization. In a large part of the genes analysed, new mutated allelic variants were found. They were submitted to the PubMLST database and subsequently annotated by the curator. All 59 study isolates were assigned to BAST types, characterized by a unique combination of allelic variants of N. meningitidis B vaccine (MenB vaccine) antigen genes. Overall, 32 different BAST types were identified, and 10 isolates either carried an unknown combination of BAST loci or a new allelic variant in some of the BAST loci. Furthermore, the MenDeVAR index, which provides information on the functional effect of MenB vaccines on a given isolate, was determined.

Conclusions: The results obtained add to the body of knowledge of the transmission of invasive and non-invasive strains of N. meningitidis in the population. The WGS analysis provided detailed data on the coverage of these strains by new MenB vaccines.