Neisseria meningitidis serogroup W135, China

Prevalence of Neisseria meningitidis serogroups in invasive meningococcal disease in China, 2010 - 2020: a systematic review and meta-analysis

Invasive meningococcal disease (IMD) caused by Neisseria meningitidis (Nm) continues to be a global public health concern. Understanding the prevalence of Nm serogroups in IMD is critical for developing strategies for meningococcal vaccination. We used the keywords “cerebrospinal meningitis”, “meningococcal”, “Neisseria meningitidis’’, “meningococcal meningitis”, “serogroup’’ and “China’’ to search five databases, including PubMed, CNKI, CBM (Chinese BioMedical Literature Database), WanFang and VIP from 2010 to 2020. The age distributions, proportions of Nm serogroups and serogroup changes in IMD were analyzed. A total of 14 studies were included according to PRISMA guidelines. In China, from 2010 to 2020, the highest proportion of Nm in IMD was NmC, with 49.7% (95% CI: 35.8%–63.5%), followed by NmB with 30.2% (95%CI:17.3%–43.0%) and NmW with 23.8% (95%CI: 7.0–40.7%). Before 2014, NmC was the major circulating serogroup, with 59.6% (95% CI: 43.8%-75.4%), followed by NmW with 24.4% (95% CI: 5.9%–42.9%). After 2015, IMD cases caused by NmB were increasing, the proportion of NmB reached to 52.4% (95% CI: 31.8%–73.1%). The age groups of children from 0 to 5 years and from 6 to 10 years represented, respectively, 29.6% (95% CI: 16.8%–42.4%) and 28.9% (95% CI: 12.1%–45.8%) of all IMD cases were reported. In China, NmB, NmC and NmW were the major serogroups causing IMD between 2010 and 2020. Since 2015, the proportion of NmB increased rapidly. The current serogroup distribution in China highlights the need of replacing the meningococcal polysaccharide vaccines that are being used in the National Immunization Program with more appropriate vaccines.

The Epidemiology of Meningococcal Disease and Carriage, Genotypic Characteristics and Antibiotic Resistance of Neisseria meningitidis Isolates in Zhejiang Province, China, 2011–2021

Neisseria meningitidis (Nm) remains a worldwide leading cause of epidemic meningitis. During 2011–July 2021, 55 meningococcal disease (MD) cases were reported with a case fatality rate of 5.45% in Zhejiang Province, China. The median age was 7 years. The annual incidence was 0.0017–0.0183 per 100,000 population. The highest age-specific incidence was observed in the group younger than 1 year. Serogroup was identified in 30 laboratory-confirmed MD cases, and MenB was most predominant. MenB was mainly observed in two age groups: younger than 5 and older than 35 years. MenB incidence was significantly increasing from 0.0018 per 100,000 in 2013 to 0.0070 per 100,000 in 2019. During 2015–2020, 17 positive samples were detected from 2,827 throat swabs from healthy population, of which 70.59% was MenB. Twenty multilocus sequence typing sequence types (STs) containing eight newly assigned STs (ST15881–ST15888) were determined in all Nm isolates. Either in MD cases or in healthy population, MenB CC ST-4821 was the predominant ST. It was worth noting that two MenY CC ST-23 cases occurred in 2019 and 2021, respectively. MenY CC ST-23 MD cases increased gradually in China. Phylogeny results based on genome sequencing indicated that Chinese MenW CC ST-11 isolates were genetically linked and grouped together with Japanese isolates, separated from MenW CC ST-11 isolates from Saudi Arabia Hajj outbreak, Europe, South Africa, South America, North America, and Oceania. MenW CC ST-11 isolates from East Asia might have evolved locally. Antibiotic susceptibility tests revealed a relatively high resistance rate (22.86%) of Nm isolates to penicillin. This study provided valuable data for Chinese public health authorities to grasp the temporal epidemiological characteristics of MD and healthy carriage.

The everchanging epidemiology of meningococcal disease worldwide and the potential for prevention through vaccination

Neisseria meningitidis is a major cause of bacterial meningitis and septicaemia worldwide and is associated with high case fatality rates and serious life-long complications among survivors. Twelve serogroups are recognised, of which six (A, B, C, W, X and Y) are responsible for nearly all cases of invasive meningococcal disease (IMD). The incidence of IMD and responsible serogroups vary widely both geographically and over time. For the first time, effective vaccines against all these serogroups are available or nearing licensure. Over the past two decades, IMD incidence has been declining across most parts of the world through a combination of successful meningococcal immunisation programmes and secular trends. The introduction of meningococcal C conjugate vaccines in the early 2000s was associated with rapid declines in meningococcal C disease, whilst implementation of a meningococcal A conjugate vaccine across the African meningitis belt led to near-elimination of meningococcal A disease. Consequently, other serogroups have become more important causes of IMD. In particular, the emergence of a hypervirulent meningococcal group W clone has led many countries to shift from monovalent meningococcal C to quadrivalent ACWY conjugate vaccines in their national immunisation programmes. Additionally, the recent licensure of two protein-based, broad-spectrum meningococcal B vaccines finally provides protection against the most common group responsible for childhood IMD across Europe and Australia. This review describes global IMD epidemiology across each continent and trends over time, the serogroups responsible for IMD, the impact of meningococcal immunisation programmes and future needs to eliminate this devastating disease.

Comparative genomic analyses of Chinese serogroup W ST-11 complex Neisseria meningitidis isolates

Although serogroup W ST-11 complex (cc11) (W:cc11) Neisseria meningitidis has been widespread in China over the past ten years, its origin and genetic relatedness has not yet been described. In this study, we described the genetic relatedness and discuss the possible origin of Chinese W:cc11 isolates by comparing their genome sequences with those of other cc11 strains globally. Comparative genomic analysis with geo-temporally diverse cc11 isolates showed that the Chinese W:cc11 isolates exclusively formed two closely related subclusters within a distinct sublineage (proposed as the Chinese-strain sublineage) of lineage 11.1 close to the interface between the Hajj-strain sublineage and the South American-strain sublineage. Several isolates from Africa and Europe were closely related to the Chinese subclusters which were largely segregated from one another among distinct provinces of China. No alleles were identified that were unique to the Chinese isolates as a whole, though each subcluster possessed unique alleles differentiating itself from the other subcluster as well as closely related isolates within the extended sublineage. Three genes differentiated the two subclusters with allele combinations that were each present among the non-Chinese isolates within the wider sublineage. These results indicate that the Chinese W:cc11 isolates formed part of a previously undescribed W:cc11 sublineage that is closely related to, but distinct from, the Hajj-strain sublineage and South American-strain sublineage. The geographical source of the Chinese subclusters was indeterminate based on available data.

Prevalence and genetic characteristics of 4CMenB and rLP2086 vaccine candidates among Neisseria meningitidis serogroup B strains, China

OBJECTIVE

To systematically investigate the prevalence and genetic characteristics of 4CMenB and rLP2086 vaccine candidates among Neisseria meningitidis serogroup B (NmB) in China.

METHODS

A total of 485 NmB strains isolated in 29 provinces of China between 1968 and 2016 were selected from the culture collection of the national reference laboratory according to the isolation year, location, and source. Multi-locus sequence typing (MLST) and porA gene sequencing were performed on all 485 study strains; PCR was used to detect the fHbp, nadA, and nhba gene of 432 strains; positive amplification products from the fHbp and nadA genes from all strains, as well as those of the nhba gene from 172 representative strains, were sequenced.

RESULTS

MLST results showed that the predominant (putative) clonal complexes (CCs) of NmB isolates have changed over time in China. While strains that could not be assigned to existing (p)CCs were the biggest proportion, CC4821 was the most prevalent lineage (36.0%) since 2005. PCR and sequence analysis revealed that the 4CMenB and rLP2086 vaccine candidates were highly diverse. Respectively, 152 PorA genotypes and 83 VR2 sequences were identified with significant diversity within a single CC; the complete nadA gene was found in ten of 432 study strains; fHbp was present in most strains (422/432) with variant 2 predominating (82.9%) in both patient- and carrier- derived isolates; almost all strains harbored the nhba gene while sequences were diverse.

CONCLUSIONS

With regards to clonal lineages and vaccine candidate proteins, NmB isolates from China were generally diverse. Further studies should be performed to evaluate the cross-protection of present vaccines against Chinese NmB strains.

Meningococcal disease and control in China: Findings and updates from the Global Meningococcal Initiative (GMI)

The Global Meningococcal Initiative (GMI) is a global expert group, including scientists, clinicians and public health officials from a wide range of specialities. The goal of the GMI is to prevent meningococcal disease worldwide through education, research, and co-operation. The Chinese GMI roundtable meeting was held in June 2017. The GMI met with local experts to gain insight into the meningococcal disease burden in China and current prevention and vaccination strategies in place. China experienced five epidemics of serogroup A meningococcal disease (MenA) between 1938 and 1977, with peak incidence of 403/100,000 recorded in 1967. MenA incidence rates have significantly declined following the universal introduction of the MenA polysaccharide vaccine in China in the 1980s. Further, surveillance data indicates changing meningococcal epidemiology in China with the emergence of new clones of serogroup B from serogroup C clonal complex (cc) 4821 due to capsular switching, and the international spread of serogroup W cc11. The importance of carriage and herd protection for controlling meningococcal disease was highlighted with the view to introduce conjugate vaccines and serogroup B vaccines into the national immunization schedule. Improved disease surveillance and standardized laboratory techniques across and within provinces will ensure optimal epidemiological monitoring.

Meningococcal disease in the Asia-Pacific region: Findings and recommendations from the Global Meningococcal Initiative

The Global Meningococcal Initiative (GMI) is a global expert group that includes scientists, clinicians, and public health officials with a wide range of specialties. The purpose of the Initiative is to promote the global prevention of meningococcal disease (MD) through education, research, and cooperation. The first Asia-Pacific regional meeting was held in November 2014. The GMI reviewed the epidemiology of MD, surveillance, and prevention strategies, and outbreak control practices from participating countries in the Asia-Pacific region.Although, in general, MD is underreported in this region, serogroup A disease is most prominent in low-income countries such as India and the Philippines, while Taiwan, Japan, and Korea reported disease from serogroups C, W, and Y. China has a mixed epidemiology of serogroups A, B, C, and W. Perspectives from countries outside of the region were also provided to provide insight into lessons learnt. Based on the available data and meeting discussions, a number of challenges and data gaps were identified and, as a consequence, several recommendations were formulated: strengthen surveillance; improve diagnosis, typing and case reporting; standardize case definitions; develop guidelines for outbreak management; and promote awareness of MD among healthcare professionals, public health officials, and the general public.

Sequence Type 4821 Clonal Complex Serogroup B Neisseria meningitidis in China, 1978-2013

Serogroup B Neisseria meningitidis strains belonging to sequence type 4821 clonal complex (CC4821), a hyperinvasive lineage first identified for serogroup C in 2003, have been increasingly isolated in China. We characterized the outer membrane protein genes of 48 serogroup B and 214 serogroup C strains belonging to CC4821 and analyzed the genomic sequences of 22 strains. Four serogroup B strains had porin A (i.e., PorA), PorB, and ferric enterobactin transport (i.e., FetA) genotypes identical to those for serogroup C. Phylogenetic analysis of the genomic sequences showed that the 22 CC4821 strains from patients and healthy carriers were unevenly clustered into 2 closely related groups; each group contained serogroup B and C strains. Serogroup B strains appeared variable at the capsule locus, and several recombination events had occurred at uncertain breakpoints. These findings suggest that CC4821 serogroup C N. meningitidis is the probable origin of highly pathogenic CC4821 serogroup B strains.

Phylogenetic study of clonal complex (CC)198 capsule null locus (cnl) genomes: A distinctive group within the species Neisseria meningitidis

Capsule null locus (cnl) strains, one type of specific unencapsulated Neisseria spp., only have regions D and E of the capsule gene cluster which encodes the genes for capsule biosynthesis, modification, and transportation. Compared with encapsulated strains, regions A and C of cnl strains have been replaced by 113 or 114 bp conserved non-coding sequences. Cnl strains include multiple clonal complexes (CC). According to previous studies, CC198 is the major clonal lineage in both cnl patients and healthy cnl carriers. We hypothesized that CC198 possesses different genome characteristics compared with other cnl strains. In this study, we obtained the draft genomes of two CC198 strains from healthy carriers. Using 75071 single nucleotide polymorphisms located in 1163 core genes, we constructed the phylogenetic relationships between a batch of representative Neisseria meningitidis genomes. CC198 and CC1136 clustered together, but apart from other N. meningitidis strains including CC53. We also aligned the sequences of genes located in regions D and E of the capsule gene locus from encapsulated and unencapsulated strains. A number of possible recombination events were identified in the galE and tex genes between different serogroups of encapsulated N. meningitidis and CC53 strains, especially in tex. In contrast, there is almost no recombination in N. meningitidis CC198 strains. These results showed that CC198 belongs to a phylogenetically distinct group within the species N. meningitidis, which may be directly derived from the cnl-type ancestor of N. meningitidis. The encapsulated strains may acquire other necessary genes for capsule formation by horizontal transfer.

CC4821 serogroup W meningococcal disease in China

Neisseria meningitidis is a major public health concern worldwide, including China. A few cases of serogroup W meningococcal disease have been reported in southeast China in recent years. Thus far, invasive disease due to W isolates has involved sequence type 11. We report two cases of N. meningitidis infection caused by CC4821 serogroup W strains.

Spread of Neisseria meningitidis serogroup W clone, China

During February 2011–June 2012, invasive infection with Neisseria meningitidis serogroup W was identified in 11 persons in southeastern China. All isolates tested had matching or near-matching pulsed-field gel electrophoresis patterns and belonged to multilocus sequence type 11. The epidemiologic investigation suggested recent transmission of this clonal complex in southeastern China.

Distribution of serogroups and sequence types in disease-associated and carrier strains of Neisseria meningitidis isolated in China between 2003 and 2008

Given the unpredictability of Neisseria meningitidis outbreaks and the increased prevalence of serogroup C strains following the introduction of serogroup A-based vaccines, we conducted an analysis of serogroups and sequence types (STs) in disease-associated and carrier N. meningitidis isolates that have emerged in China since 2003. We used multilocus sequence-typing techniques to investigate 371 N. meningitidis strains isolated from patients with meningitis and healthy carriers. Two lineages were identified in serogroup A and C isolates, genotyped as the ST5 complex and ST4821 complex, respectively. Both clonal complexes were found throughout China, although ST4821 was more concentrated in the eastern region of the country. The ST5 complex has been persistent in China since the late 1980s and has since spread across the entire country. Isolates belonging to the ST4821 complex have been a dominant lineage since 2003.