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INTRODUCTIONThe study presents the results of the genomic surveillance of invasive meningococcal disease (IMD) in the Czech Republic for the period of 2015–2017.MATERIAL AND METHODSThe study set includes all IMD isolates recovered in the Czech Republic and referred to the National Reference Laboratory for Meningococcal Infections in 2015-2017, a total of 89 N. meningitidis isolates (20 from 2015, 27 from 2016, and 42 from 2017). All isolates were studied by whole genome sequencing (WGS). RESULTSSerogroup B was the most common, followed by serogroups C, W, and Y. Altogether 17 clonal complexes were identified, the most common of which was hypervirulent clonal complex cc11, followed by cc32, cc41/44, cc269, and cc865. Over the three study years, hypervirulent cc11 (serogroup C) showed a statistically significant upward trend. The WGS method showed two clearly differentiated clusters of N. meningitidis C, cc11. The first cluster is represented by nine isolates, all of which are from 2017. The second cluster consist five isolates from 2016 and eight isolates from 2017. Their genetic discordance is illustrated by the changing the nadA allele and consequently by the variance their BAST type. Clonal complex cc269 (serogroup B) also increased. WGS identified the presence of MenB vaccine antigen genes in all serogroup B and non-B isolates of N. meningitidis. Altogether 49 different BAST types (combinations of peptide variants of MenB vaccine antigen genes) were identified and 10 combinations of these have not been previously described in the PubMLST database. CONCLUSIONSThe genomic surveillance of IMD in the Czech Republic provides data needed to update immunisation guidelines for this disease. WGS showed a higher discrimination power and provided more accurate data on molecular characteristics and genetic relationships among invasive N. meningitidis isolates. |