Genomic surveillance of invasive meningococcal disease in the Czech Republic, 2015-2017

Whole genome analysis of Neisseria meningitidis isolates from invasive meningococcal disease collected in the Czech Republic over 28 years (1993-2020)

Invasive meningococcal disease belongs among the most dangerous infectious diseases in the world. Several polysaccharide conjugate vaccines against serogroups A, C, W and Y are available and two recombinant peptide vaccines against serogroup B (MenB vaccines) have been developed: MenB-4C (Bexsero) and MenB-fHbp (Trumenba). The aim of this study was to define the clonal composition of the Neisseria meningitidis population in the Czech Republic, to determine changes in this population over time and to estimate the theoretical coverage of isolates by MenB vaccines. This study presents the analysis of whole genome sequencing data of 369 Czech N. meningitidis isolates from invasive meningococcal disease covering 28 years. Serogroup B isolates (MenB) showed high heterogeneity and the most common clonal complexes were cc18, cc32, cc35, cc41/44, and cc269. Isolates of clonal complex cc11 were predominately serogroup C (MenC). The highest number of serogroup W isolates (MenW) belonged to clonal complex cc865, which we described as exclusive to the Czech Republic. Our study supports the theory that this cc865 subpopulation originated in the Czech Republic from MenB isolates by a capsule switching mechanism. A dominant clonal complex of serogroup Y isolates (MenY) was cc23, which formed two genetically quite distant subpopulations and which showed constant representation throughout the observed period. The theoretical coverage of isolates by two MenB vaccines was determined using the Meningococcal Deduced Vaccine Antigen Reactivity Index (MenDeVAR). Estimated Bexsero vaccine coverage was 70.6% (for MenB) and 62.2% (for MenC, W, Y). For Trumenba vaccine, estimated coverage was 74.6% (for MenB) and 65.7% (for MenC, W, Y). Our results demonstrated sufficient coverage of Czech heterogeneous population of N. meningitidis with MenB vaccines and, together with surveillance data on invasive meningococcal disease in the Czech Republic, were the basis for updating recommendations for vaccination against invasive meningococcal disease.

Molecular characterization of invasive Neisseria meningitidis isolates collected in Lithuania (2009-2019) and estimation of serogroup B meningococcal vaccine 4CMenB and MenB-Fhbp coverage

Neisseria meningitidis causes invasive meningococcal disease (IMD), which is associated with significant mortality and long-term consequences, especially among young children. The incidence of IMD in Lithuania was among the highest in European Union/European Economic Area countries during the past two decades; however, the characterization of meningococcal isolates by molecular typing methods has not yet been performed. In this study, we characterized invasive meningococcal isolates (n=294) recovered in Lithuania from 2009 to 2019 by multilocus sequence typing (MLST) and typing of antigens FetA and PorA. The more recent (2017-2019) serogroup B isolates (n=60) were genotyped by analyzing vaccine-related antigens to evaluate their coverage by four-component (4CMenB) and two-component (MenB-Fhbp) vaccines using the genetic Meningococcal Antigen Typing System (gMATS) and Meningococcal Deduced Vaccine Antigen Reactivity (MenDeVAR) Index methods, respectively. The vast majority (90.5%) of isolates belonged to serogroup B. MLST revealed a predominance of clonal complex 32 (74.02%). Serogroup B strain P1.19,15: F4-28: ST-34 (cc32) accounted for 64.1% of IMD isolates. The overall level of strain coverage by the 4MenB vaccine was 94.8% (CI 85.9-98.2%). Most serogroup B isolates (87.9%) were covered by a single vaccine antigen, most commonly Fhbp peptide variant 1 (84.5% of isolates). The Fhbp peptides included in the MenB-Fhbp vaccine were not detected among the analyzed invasive isolates; however, the identified predominant variant 1 was considered cross-reactive. In total, 88.1% (CI 77.5-94.1) of isolates were predicted to be covered by the MenB-Fhbp vaccine. In conclusion, both serogroup B vaccines demonstrate potential to protect against IMD in Lithuania.

Characterisation of Neisseria meningitidis cc11/ET-15 variant by whole genome sequencing

BACKGROUND

Neisseria meningitidis strains belonging to clonal complex 11 is the cause of numerous outbreaks and epidemics in the United States, Canada and Europe, accounting for 49.5% of cases of meningococcal disease caused by serogroup C worldwide. In Brazil, it is the second most frequent clonal complex within this serogroup. The genetic characterisation of cc11/ET-15 variants is important for the epidemiological monitoring of meningococcal disease, through the identification of circulating epidemic clones, to support specific actions of Health Surveillance aiming outbreaks control.

OBJECTIVES

The objective of this study was to identify features in the genome of cc11/ET-15 clones through whole-genome sequencing (WGS), that differ from cc11/non-ET-15 strains that could explain their virulence.

METHODS

The whole genome of three cc11/ET-15 representative strains were sequenced with a minimum coverage of 100X with the MiSeq System and compared to the genome of cc11/non-ET-15 strains.

RESULTS

Genome analysis of cc11/ET-15 variants showed the presence of resistance factors, mobile genetic elements and virulence factors not found in cc11/non-ET-15 strains.

MAIN CONCLUSIONS

Our results show that these strains carry virulence factors not identified in cc11/non-ET-15 strains, which could explain the high lethality rates attributed to this clone worldwide.

Whole genome sequencing of Neisseria meningitidis Y isolates collected in the Czech Republic in 1993-2018

Introduction

The study presents the analysis of whole genome sequencing (WGS) data for Neisseria meningitidis serogroup Y isolates collected in the Czech Republic and their comparison to other countries. The aim of the study was to determine whether there are lineages of N. meningitidis serogroup Y in the Czech Republic genetically related to foreign ones that have been causing an increase of the morbidity and the mortality of invasive meningococcal disease (IMD) world-wide recently.

Material and methods

The WGS data of 43 Czech N. meningitidis Y isolates, 35 from IMD and 8 from healthy carriers were analysed. Due to the potential of meningococcal B vaccines to induce protection against non-B serogroups, the coverage of Czech isolates of N. meningitidis Y by these vaccines was studied. The WGS data of Czech, European and non-European isolates of N. meningitidis serogroup Y were compared.

Results

WGS assigned 36 isolates of N. meningitidis Y to five clonal complexes: cc23, cc92, cc167, cc103, and cc174, while seven isolates remained unassigned to any clonal complexes (ccUA). Eighteen invasive isolates belonged to clonal complex cc23, which was detected throughout the studied years. The occurrence of cc23 was recorded in all age groups of IMD patients, with the highest found in those aged 15–19 years. On the phylogenetic network isolates of cc23 form a separate lineage, distinct from all other isolates of N. meningitidis Y. The remaining isolates were assigned to other clonal complexes and have very low relatedness to cc23 isolates and to each other. The comparison with foreign WGS data showed that within the main genetic lineages, which are defined by clonal complexes, Czech isolates of N. meningitidis Y, similar to European ones, mostly cluster together and form geographical sublineages.

Conclusions

WGS analysis showed the population of Czech N. meningitidis Y isolates as relatively heterogeneous, containing a large number of genetic lineages. The Czech isolates of N. meningitidis Y follow the trend observed for European isolates. Our result was one of the bases for updating the recommended vaccination strategy in the Czech Republic.

Meningococcal B vaccine antigen FHbp variants among disease-causing Neisseria meningitidis B isolates, Italy, 2014-2017

Background

Typing of Neisseria meningitidis isolates is crucial for the surveillance of invasive meningococcal disease (IMD). We performed a molecular epidemiology study of N. meningitidis serogroup B (MenB) causing IMD in Italy between 2014 and 2017 to describe circulating strains belonging to this serogroup, with particular regards to the two factor H-binding protein (FHbp) subfamilies present in the bivalent MenB vaccine.

Materials and methods

A total of 109 culture positive and 46 culture negative MenB samples were collected within the National Surveillance System (NSS) of IMD in Italy and molecularly analyzed by conventional methods.

Results

Overall, 71 MenB samples showed the FHbp subfamily A and 83 the subfamily B. The subfamily variants were differently distributed by age. The most frequent variants, A05 and B231, were associated with cc213 and cc162, respectively. All MenB with the FHbp A05 variant displayed the PorA P1.22,14 and 85.7% of them the FetA F5-5. The majority of MenB with the FHbp B231 variant showed the PorA P1.22,14 (65.4%) and 84.6%, the FetA F3-6.

Conclusion

MenB circulating in Italy were characterized by a remarkable association between clonal complex and FHbp variants, although a high degree of genetic diversity observed over time. A dynamic trend in clonal complexes distribution within MenB was detected. Our results stress the importance of continued meningococcal molecular surveillance to evaluate the potential vaccine coverage of the available MenB vaccines.

Molecular characterization of Neisseria meningitidis isolates recovered from patients with invasive meningococcal disease in Colombia from 2013 to 2016

BACKGROUND

Neisseria meningitidis is a significant cause of morbidity and mortality worldwide. Meningococcal isolates have a highly dynamic population structure and can be phenotypically and genetically differentiated into serogroups and clonal complexes. The aim of this study was to describe the phenotypic and genotypic characteristics of invasive isolates recovered in Colombia from 2013 to 2016.

METHODOLOGY

A total of 193 invasive isolates were analyzed. Phenotypic and genotypic characteristics were determined by serotyping, antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing.

RESULTS

Based on the results, meningococcal serogroups C, B and Y were responsible for 47.9%, 41.7%, and 9.4% of cases, respectively, and the distribution of serogroups B and C changed over time. Fifteen clonal groups and 14 clonal complexes (cc) were identified by PFGE and genome sequencing. The main clonal group included serogroup B isolates with sequence type (ST)-9493 and its four single-locus variants, which has only been identified in Colombian isolates. The clonal population structure demonstrates that the isolates in this study mainly belong to four clonal complexes: ST-11 cc, ST-32 cc, ST-35 cc and ST-41/44 cc. Thirty-eight penA alleles were identified, but no correlation between MICs and specific sequences was observed.

CONCLUSION

This study shows that most meningococcal isolates recovered from patients with invasive meningococcal disease in Colombia are strains associated with distinct globally disseminated hyperinvasive clones.

Prevention and control of meningococcal disease: Updates from the Global Meningococcal Initiative in Eastern Europe

The Global Meningococcal Initiative (GMI) aims to prevent invasive meningococcal disease (IMD) worldwide through education, research and cooperation. In March 2019, a GMI meeting was held with a multidisciplinary group of experts and representatives from countries within Eastern Europe. Across the countries represented, IMD surveillance is largely in place, with incidence declining in recent decades and now generally at <1 case per 100,000 persons per year. Predominating serogroups are B and C, followed by A, and cases attributable to serogroups W, X and Y are emerging. Available vaccines differ between countries, are generally not included in immunization programs and provided to high-risk groups only. Available vaccines include both conjugate and polysaccharide vaccines; however, current data and GMI recommendations advocate the use of conjugate vaccines, where possible, due to the ability to interrupt the acquisition of carriage. Ongoing carriage studies are expected to inform vaccine effectiveness and immunization schedules. Additionally, IMD prevention and control should be guided by monitoring outbreak progression and the emergence and international spread of strains and antibiotic resistance through use of genomic analyses and implementation of World Health Organization initiatives. Protection of high-risk groups (such as those with complement deficiencies, laboratory workers, migrants and refugees) is recommended.